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hz numbers on a 15" 2 driver (Read 27120 times)
morpheous85
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #100 - 05/12/06 at 23:46:22
 
When I was talking about a box around the projector, I was thinking that to be practical heat wise (and to be an improvement sound wise), it'd basically need it's own ventilation duct. Might just be easier to do the separate room thing.

Jason
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #101 - 05/13/06 at 00:41:19
 
With the lowered ceiling above your PJjust throw another fan in parralel with the fan on the projector.  The place that fan in the ceilign tile.  Build a box with a cut out for you lens, so just the tip sticks out.

Fan sucks heat from projector into lowered ceiling.  Movie goers are totally isolated from sound of fans.  And Pj is better braced against vibrations.

Heres a pick: (minus the walls, so you can see)



Notice the awesome fan I drew up?
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« Last Edit: 05/13/06 at 00:41:41 by j_rock777 »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #102 - 05/13/06 at 02:33:11
 
That's not enough ventilation.  The only way I'd box up a projector is if I was sure the projector was getting more fresh air flow than the projector got naturally.  You would need some kind of ductwork going to the intake.  Most projectors have multiple fans front and back, plus another one to force air through the bulb housing.
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gexter
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #103 - 05/13/06 at 06:25:35
 
Anything I have to keep cool I keep it cooler.
I tend to replace anything with a fast moving loud fan with a larger slow moving one. preferably with twice the CFM.
Nasty habit left over from Being a PC modder and overclocker.
I also undervolt the oversized fan and then add or subtract resistors to find the temp I am comfortable with.
this applies to 12 v fans. you also have to watch for keeping the voltage higher than start up voltage.
if it don't spin at 7V you need another fan to use with a lower startup voltage, as an example.

I know you can build a circuit to solve this but I am too lazy.

Blowing air in and in bigger quanitities leads to more dust unless your filtering and then you have filters to check.
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« Last Edit: 05/14/06 at 14:33:20 by gexter »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #104 - 05/15/06 at 11:56:16
 
[quote author=John in CR  link=1145573673/90#100 date=1147473332]
I want to see smileys on Monday. [/quote]


Ok John, here's the smiley after the mods......  :(   Cry

I've got numbers, I'll be 'organizing' them today. Will post when they're in a 'readable form'

Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #105 - 05/15/06 at 12:32:29
 
Bob,

Before the numbers, please tell me exactly what you did in the way of mods first.  After reading that you painted a deck, I'm not sure what to expect.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #106 - 05/15/06 at 13:33:42
 
LOL John,

I didn't use 'regular' paint, it was supposed to be 'FOR' exterior use.  ::)

http://www.behr.com/behrx/act/view/products_detail?prodGroupId=53&catName=Wood+W...

OK, here we go...

- Removed both caps
- Removed both drivers
- Sealed one of the lower holes
- Installed 13" X 4" PVC port tube in other lower hole (slightly enlarging the original hole
- installed lower cap
- clamshelled both drivers in upper chamber (left the cap off)
- wired out of phase

Look ok? ) I think there may have been a Budwieser or two in there as well.  ;)

Bob
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #107 - 05/15/06 at 14:12:48
 
Sorry Bob, just couldn't resist.  I already knew decks were stain only (if anything other than just sealer).  Before I may have tried paint too.

It sounds like you did everything right.  What did the sub sound like?  My guess before hearing your result is that you wired in series instead of parallel (sorry I didn't mention that before) or maybe a receiver setting, amp problem, loose wire etc.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #108 - 05/15/06 at 14:35:10
 
[quote author=John in CR  link=1145573673/105#108 date=1147698768]Sorry Bob, just couldn't resist.    [/quote]

No harm done, I can take it.  :D Undecided Kiss

Wiring comes from amp to the ,... oh, what's it called, the "terminal block" on the sub. Inside the sub, the individual driver wires go directly to the spades on the back of the block, like a "Y" connection. ALL connections are soldiered, soldered? Dammit man, can't spell on a good day, much less a Monday morning.

Is that wired ok?

As far as sound quality goes, I "THINK" it was better, but I was more intent on looking at the meter than listening to quality (although I was listening for Mr. Klop to come to the door  :-X ). It was getting late and testing max SPL on Mothers day evening at dinner time was starting to strain the WAF. Main goal was to get numbers.

Went to Radio Shack to get the meter, the man said they don't have the analog meter anymore. "BUT, here's this cool nifty looking digital meter that's sooooo much cooler".  ::)
Never liked looking at a digital meter for things that "move" across a spectrum rapidly. That's what analog is for. The damn thing was $57 with tax, including the $3 9volt battery they ganked me for.
Shouldn't have bought it, I SHOULD have held out for a "real" meter, but when I have my heart set on something, It's mine. (Just like my 7 year old...Gotta have it now or the world will stop turning.)
Thinking about taking it back?

Here it is.....

http://www.radioshack.com/product/index.jsp?productId=2103667&cp=&origkw=sound+l...


Bob
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« Last Edit: 05/15/06 at 14:36:42 by Bob »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #109 - 05/15/06 at 15:33:13
 
Wiring-  Series, parallel or separate?  Series means through one driver to the other then back to the amp.

Did Mr. Klop show up?

What were you playing during your test?  Test tones?

I have an SPL meter.  How many times have I used it?...Less than I have fingers.  How many times have I used it for a sub?...None

Did you put Nemo on and see if it felt like you were in the fish tank when Darla was tapping?  That's a really good test.  Do you have Harry Potter 2?  The willow whomping the car is also good because it has a good variation of frequency as it groans with a nice impact to really feel when it slams to the ground.  Also, the train scene about a minute earlier.  You should feel the near miss of a raging locomotive.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #110 - 05/15/06 at 16:11:00
 
Ok, did (4) tests. First 3 were done never touching amp setting I have it set so the Daytons "just barely" klop. Last test turning amp output from 40% of max to 50% of max. 1st with unmodded HWK, 2nd after mod, 3rd after reinstalling top cap (just for grins) and 4th with more amp power. Chapter 3 in Star Wars III has two fairly long LFE rumbles, and Master & Commander, Chapter 4 has a nice cannon volley.

In parensesis is an (sk), that means I heard a "Slight Knock" from the drivers. No (sk) obviously means no knock heard. the "xxxx" on Master and Commander means the WAF had reached "IT'S max excursion"   Lips Sealed
Measurement taken at ear height, in the center of the 4 HT seats. ( also did a 3' foot distance measurement from the 4" port. The numbers mirrored the seated position measurement, just a few db's higher of course. )

STAR WARS III (chapter 3, 1st and 2nd extended LFE rumbles)


           Decware HKW       after mod      top cap    50% amp
1st rumble   105db(sk)        104db(sk)     105db      107db(sk)
2nd rumble   108db(sk)        107db(sk)    108db      109db(sk)

Master and Commander Chapter 4 Cannon volley
                104(sk)            103db          105db      xxxx

By the way, my 6 horsepower Campbell Hausfeld air compressor produces 88 db from 3 feet.  ;)
Will post numbers at a later date on what my 2 year old daughter can produce db speaking. Would like to know the hz rating. She can reach some unbelievable highs hz AND db's.  :D

Bob
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #111 - 05/15/06 at 16:56:37
 
[quote author=John in CR  link=1145573673/105#110 date=1147703593] Series means through one driver to the other then back to the amp. [/quote]

...."back to" the amp?  The "back" is thowing me off..?
Positive and negative to the sub, then "Y" to each individual driver, like a fork in the road.

Nemo on DVD was borrowed, the kids only have it on VHS. I won't even install a VHS in the room, imagine what 480X480 looks like blown up that big....  :-X

haven't tried tones with the meter. The Potter movie you mentioned is on my 'needed' list.  :)

Bob
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #112 - 05/15/06 at 17:40:09
 
Bob,

First, shame on you for testing your sub on Mothers' Day.  You burned up any credits you had and need to do something extra special to get some back.

Second, your tests don't really mean much at all except that they play up to 105db+ at the seating position and that you're playing low enough frequency info to send both the HWK and ported alignments into over excursion.  What it doesn't tell you is how low in frequency you were getting what output.  

Those LFE's have a wide range of frequencies in them.  The cannon shots, for example, probably have a burst across the entire range below the XO point set on your receiver all the way down to about 10hz.  It doesn't surprize me at all that the output was close to equal.  What it doesn't show is a comparison at say 20hz or lower.  Could you hear/feel a significant difference or were you too busy with your new gadget?  Was it enough feel or do you need more, because 105db is pretty darn loud?

If you like the tuning with the top on, that will give you the ability to go louder, because the top chamber is helping to control excursion better than the free air of the open top.

Put the ported end in the corner.  That will give you some boost on the bottom.

Lower tuning (longer port) will enable you to apply more power (go louder and lower) before going into overexcursion on the lowest material.

You should walk around the room while playing the Star Wars rumble to make sure you don't have a placement issue putting your seating area in a relative null.

If after trying all of that you are positive that you want more output, then you need 2 larger boxes, ported and tuned to the frequency you want  OR make your room so it can be closed, which will probably net you about 10db of room gain down at the bottom end of the range.  Your open floor plan prevents much at all in the way of room gain.  Two boxes will net you +6db at the same total power.  Half of your power is currently going to waste for no gain (except smaller cab size) with the isobarik alignment.  You double the alignment (+3db) and double the useful power (+3db).  If you are sure you need more, I'd try HWK size first with only one driver, in place of the top cap, and tuned even lower with say a 17" port.

Something to keep in mind is that with this very low tuning you are getting a shelved response, Extended Bass Shelf (EBS).  Below about 50hz the output drops by 5-6db and stays fairly level down to port tuning.  Typically this is a good match when room gain is factored in netting a pretty flat response.  A max flat response would require tuning to 25hz or so, and you'd give up bottom end extension.  I just question how much room gain you are getting.

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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #113 - 05/15/06 at 18:35:49
 
[quote author=John in CR  link=1145573673/105#113 date=1147711209]Bob,

First, shame on you for testing your sub on Mothers' Day.  You burned up any credits you had and need to do something extra special to get some back.
[/quote]

Fortunately we have a very stong marriage ( ie...she tolorates my toys)

[/quote]
Second, your tests don't really mean much at all except that they play up to 105db+ at the seating position and that you're playing low enough frequency info to send both the HWK and ported alignments into over excursion.  What it doesn't tell you is how low in frequency you were getting what output.  
[/quote]

Is there something a fellow could get to measure hz and db simultaneously, or would that be yet another toy in the hands of someone not needing more toys?

[/quote]
Those LFE's have a wide range of frequencies in them.  The cannon shots, for example, probably have a burst across the entire range below the XO point set on your receiver all the way down to about 10hz.  It doesn't surprize me at all that the output was close to equal.  What it doesn't show is a comparison at say 20hz or lower.  Could you hear/feel a significant difference or were you too busy with your new gadget?  Was it enough feel or do you need more, because 105db is pretty darn loud?
[/quote]

I believe it was you that said something about the level of sanity regarding your subs.  :) Am I correct  ;D  Yes, I was mainly concerned with the toy last night, but it seemed to be better. Over the next few days, I'll have some real play time to actually HEAR it.

[/quote]
If you like the tuning with the top on, that will give you the ability to go louder, because the top chamber is helping to control excursion better than the free air of the open top.
[/quote]

Would making the top port a smaller diameter create more air restriction, giving the ability to go louder?

[/quote]
Lower tuning (longer port) will enable you to apply more power (go louder and lower) before going into overexcursion on the lowest material.
[/quote]

Install a 90 degree fitting on the PVC to add additional pipe?

[/quote]
If after trying all of that you are positive that you want more output,
[/quote]

Absolutely

[/quote]
OR make your room so it can be closed,
[/quote]

Very hard to do with the archway. Light switch just out of view on right side of arch. And there would be three doorways in very close proximity of each other, all swinging towards each other.

[/quote]
If you are sure you need more, I'd try HWK size first with only one driver, in place of the top cap, and tuned even lower with say a 17" port.
[/quote]

I'd like to go down this path.


...Gee, I hope all this quoting works.

Bob
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #114 - 05/15/06 at 18:37:36
 
Well, that looks like hell. But I suppose a fairly smart guy could figure what it was I was attempting to do.   Roll Eyes

Bob
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« Last Edit: 05/15/06 at 18:38:17 by Bob »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #115 - 05/15/06 at 19:46:22
 
Google  "ttg test tone generator free" and download Timo Esser's tone generator that is free for a month.  If your puter isn't connected to your system, just make some tone files and sweeps and burn them on a disk.  Then you play a frequency from the generator and measure it with the SPL meter.

Be absolutely sure your other speakers are set to small or are off for running that kind of test or you'll blow them for sure.

Keep the port outside the box, so you can easily try different lengths first.  Don't put it inside until you get to the tuning you want.

You might be able to get away with a matched pair at the front of the room in the corners with the right color scheme.  I think that will load your room better, but that's probably just a few dbs at most.

Before building something new, check the SQ and max limits with the top cap on.  Also with the top off and lower tuning.

Yes I think a smaller diameter port and/or longer port will help control excursion to a lower frequency, but too low tuning could cancel some output from the big chambered end because they are at a different phase.

Just for grins, next time you have a sheet of ply or mdf, before you cut on it, place it over the opening leading out of the room and have someone hold it in place while you play some loud LFE's to see how much more room gain is possible.  That way you know whether or not it's worth trying to figure out if it's worth any trouble trying to make that work.

I'd say measure and listen to what you have first.  Going for extreme output is kinda fun, but realistically it will never be used, because your volume would be up way too loud for the rest of the audio spectrum.  Plus, if you do use it, you'd have to start worrying about cracks in sheetrock joints and other damage to your house.  Also, Dad's setting the example now, you may not enjoy the 7yro's taste in music in a few years and he/she will want to blast their's too.

Keep in mind that HWK size is about 100L too small for true EBS tuning.  It looks like Bassboy and I are going to try some new that we've been discussing over in the HT section.  If my 10hz version works, using a 15" driver, then that might be your answer once you want to cut some wood.  Tom Danely, a renown sub designer, is getting 120+db at 20hz with a pretty compact model with a 12" driver.  Mine will be 8ft x 1.5ft x 3 or 4ft and it looks like you have room for that behind your seating area.  http://news.ecoustics.com/bbs/messages/10381/169045.html
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #116 - 05/15/06 at 22:15:24
 
John, that's a lot of very good advise you just gave. Endless tweeking..... Several weekends worth I'm sure.

I like the specs on the HVAC cold air return you gave ( well, that's what it looks like  :) ). Very impressive. But for 3 grand + shipping + suitable amp, I can play in my toy room for a looong time spending the $$$ elseware.

I have been lurking the thread with yourself and bassboy with great interest. Yes I'm luck in that respect, PLENTY or room behind the seating. (unplanned, over-exagerated projector throw distance/screen size specs given by the manufacturer provided me with lots of extra room. Putting the seating where it was originally planned would put the PJ at adams apple level imediately after standing up from the seats.  >:()

I have thought about a temporary "door" but if memory serves, the opening is 5'wide 7'tall. Would have to make something. Really regret not having a door there. Didn't think I needed one 3 years ago when I built it.

Thanks again John. I'll be hanging in the HT thread to see what my next POSSIBLE project would be if the HWK doesn't work out.

Bob
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #117 - 05/18/06 at 22:39:17
 
[quote author=John in CR  link=1145573673/105#116 date=1147718782]
Keep the port outside the box, so you can easily try different lengths first.  Don't put it inside until you get to the tuning you want. [/quote]

So, let me get this right.  The total port lenth isn't the issue, it's how much of it is inside the enclosure? Does it affect tuning at ALL, or just not enough to worry about for tuning purposes only?

Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #118 - 05/18/06 at 22:56:44
 
[quote author=Bob  link=1145573673/105#118 date=1147988357]

So, let me get this right.  The total port lenth isn't the issue, it's how much of it is inside the enclosure? Does it affect tuning at ALL, or just not enough to worry about for tuning purposes only?

Bob [/quote]

Bob,
The port length and diameter is the only issue with a cab that large.  When it's inside the box, the volume taken up by the port (and the volume taken up by the driver) is subtracted from the total volume to get to the Vb (the volume of air being tuned).  In your case the volume taken up by the port is immaterial in comparison, so you can determine the tuning you want by fiddling with your port length with it outside of the cab.  When you get to where you want, then worry about how to fit it inside the cab.  ie  Don't worry about 90 degree bends and stuff now.  Also, you can try different tuning in seconds, instead of having to take the bottom cap off and make changes.
John
the world's foremost believer in the KISS principle.
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #119 - 05/19/06 at 00:50:59
 
I have been whatching this thread for some time.  I believe for home theatre you need to stop and step back.

Now realize the HWK is not going to work.

Now start over from scratch.  Working around the space, drivers and amps you have, design a new enclosure.  For hometheatre and double duty as music, the only option IMO is a low tuned ported enclosure (PR if needed).  

No offense, these ideas are great, but I think you have a much better idea of what you want, and can easily get it without haveing to modify a box.

And guessing at volumes and ports is fun for a few hours, but after awhile grows tiring, I suggest a program to model something.  Even if it is just to get a starting point...

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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #120 - 05/19/06 at 01:42:20
 
J_Rock,

You haven't been reading very closely.  Bob's HWK has been converted to a low tuned BR using only minor changes and NOT having to build a whole new box.  I did some quick and dirty modelling for him and using the center and bottom chambers as his Vb, he could tune pretty low using isobarik loading.  Now he's going to measure what he has, to figure out where he wants to go.

If his mains reached down to 40hz, then the HWKenstein would be the most compact way to get prodigous output down in the low teens.  The alternative is 2 big (350L+) BR boxes, if the isobarik BR doesn't have enough output.  About the only thing that hasn't been discussed is a rumble filter to protect his drivers from over-excursion.  Before getting into that, I was just going to let him run some tests with a longer port.
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J_Rock
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Re: hz numbers on a 15" 2 driver
Reply #121 - 05/19/06 at 02:45:11
 
I understand that much, I am suggesting that he DOES start over.  

Of course after testing the HWKenstien.

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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #122 - 05/19/06 at 03:13:38
 
[quote author=J_Rock  link=1145573673/120#122 date=1148003111]I understand that much, I am suggesting that he DOES start over.  

Of course after testing the HWKenstien.
[/quote]

He can't really use HWKenstein, even though I'd like to hear about it too.  The thing is, he already has a finished 200+L solid cab.  Using the 150+L of the bottom 2 chambers of his HWK may work until he builds new mains.  The 6th order BP with the HWK top cap on may even work well enough as a stop gap.  Another option to try is to iso mount the drivers in place of the top cap.  That will allow more optimum mid teens tuning of the ready made BR alignment.  Starting from scratch cabwise is the last thing I'd do.
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #123 - 05/19/06 at 12:21:30
 
LOVING the discussion guys, keep going..  ;D

Weekends are best for letting the HWK "stretch it's legs" so to speek. So I havn't done much listening at high db's during this past week. I do believe it sounds better John. However, I am looking to go lower in the hz, and higher in the db's.  

Tell me if this correct..."Adjusting the port lenth will only change hz range, and not affect db's or prevent driver bottoming out".

If this is true then I would be interested in exploring other modifications. ie, trying iso loading drivers mounted ON the top cap, increasing Vb, or...?... letting more sawdust fly?

Tell me what this would do,...
- Lay original HWK on it's side, facing dual port holes up
- Build carbon copy HWK enclosure facing dual port holes down
- Lay it on it's side, on top of other HWK (the, now "quad holes", mating with each other
- iso mount drivers in the top cap of, say... bottom HWK
- install the adjustable port(s) in 'what would have been' the top cap of upper HWK (now the end of the upper HWK)

Anybody for some ascii?.....
                                                         
                                                         
     -----------------------------------
     I                                               I
     I                                          -----    /__ ADJ. PORT
     I                                          -----    \
     I                                               I
     --    ------------------------------I
     I                                            __/
     I                                           [        /___ ISO DRIVERS
     I                                           [__     \
     I                                               \
     -----------------------------------I

Bob
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #124 - 05/19/06 at 13:56:11
 
no way im going to read all this thread, but if the origional hwk is a good desighn (and im assumeing because steve d desighned it, it is) why all the modding? if built to plans with the right drivers it will deliver lots of accurate bass.mine does anyway ??? in a nutshell, whats wrong with the origional hwk for your application bob?
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #125 - 05/19/06 at 14:00:26
 
turning the knob up just creates the horrible 'klopping' sound from drivers hitting mechanical limit.



ah, the above quote is from bobs first post and seems to be where it all started.seems to me like you need heavier duty drivers. 900 wrms @ 25hz is gonna punish most mediocre drivers.
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #126 - 05/19/06 at 14:02:07
 
[quote author=Adrian D.  link=1145573673/0#2 date=1145626960]series II have only 8mm xmax and can handle 'only' 300w. so my guess is that, with 450w to each of them they're bottoming out.

[/quote]

post number 5?
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #127 - 05/19/06 at 14:04:17
 
[quote author=Bob  link=1145573673/0#3 date=1145628689]Sorry Adrian, I assumed the world centered around me, and that everyone had read the entire thread "amp to make Daytons happy".  ::)  :'(



The Daytons I've got are the series II. They've got an xmas of 15.1, and rms watts of 350, 600 max.

[/quote]

450 still pushes them beyond theyre ability.especially when you really want all that output below 50hz!
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #128 - 05/19/06 at 14:17:01
 
Even when the amp gain is at 40%?  :'(

Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #129 - 05/19/06 at 14:18:50
 
Hi Bob,

Lower tuning by lengthening the port will give you excursion control down to a lower frequency, so playing the same content as your last test, you should be able to turn it louder before running into excursion problems.

The tuning frequency of your box is determined only by the net volume of enclosed and the diameter and length of your port.  Increasing the volume, lengthening the port, or decreasing port diameter lowers tuning.  Content below the tuning frequency quickly causes excursion problems, because the alignment can handle very little power below tuning.  Typically a "rumble filter" a high pass filter is used to protect your driver from content below tuning.

The T/S parameters of your driver determine what size box is needed for optimum performance tuned to a specific frequency.  Isobarik loading cuts the Vas in half and the driver only needs to see half the box size for the same performance at a given port tuning.  With iso loading you don't need any more box than you already have.  In fact, the way you have the drivers mounted now gives you an effective volume equal to almost 340L for a single driver and moving the drivers up to the top cap wouldn't help.

At this point I'd suggest trying 2 things:  

First, see if you can live with the SQ and tuning of your current box with the top cap back on.  That alignment will give you more excursion control down low, but it will also limit integration with your mains.  As you saw last weekend, it will allow higher output with the content you were playing in your test.

If that setup won't work for you, then try tuning the existing setup to a lower frequency with some longer ports.

You can use the LFE's you used before for your testing to give you an idea of performance, however, you don't know low that content goes.  I'd mix some more LFE's in for that kind of testing.  Let's say you're tuned to 15hz and the LFE's have 10hz content, you won't be able to turn it very loud and see how your sub performs from 15hz and up.  If you tune to 10hz, then you'll give up a lot of max performance compared to 15hz tuning.  That's where the tone generator comes into play, because it will enable to properly test performance and extension.  Then once you determine the desired tuning frequency, you know what rumble filter you need to protect your drivers which will enable you to crank it as loud as you want without the banging noise no matter what LFE's you send to it.

The bottom line is that you really don't need to let any sawdust fly, because HWKenstein won't integrate with your system.  After trying the stuff above, and you're still feeling adventuresome, then you could try just a single driver (not iso) mounted in place of the top cap using your current port.  That will give you a slightly underdamped alignment close to an EBS alignment.  It won't give you any more output or driver protection below tuning, although it would lower tuning by a couple of Hz compared to what you have now.  It will just tell you what to expect with 2 of the same boxes.  Just test it and add 6db.

You already have butt shakers, so realistically you don't need super low tuning for your sub, you just need a rumble filter.
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #130 - 05/19/06 at 14:27:02
 
i saw some pictures recently of i think your ht room? if that really is how serious you are about your ht then getting something like these



http://www.ddaudio.com/dd/caraudio/woofers.asp?series=3500d


is definately not out of the question.imo Wink
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #131 - 05/19/06 at 16:47:18
 
Even more good advise John, That'll keep me busy for awhile.  ;D

Hey 60, a 10.6 lb magnet, OMG! 3 inches Xmas, OMG!!! that's cool, but they arn't very forthcoming with prices are they?
Yes, to answer your question, I am serious about the room. Usually as serious as my budget allows  ::)
2X4's and drywall are cheap, so you can do cool things with design that increase the cool factor and help acustically (hopefully)
As far as the butt shakers go, they stopped working last night!?  ??? Cry
I've heard may referances to rumble filters, mostly seeing plate amps with the filter built in, but I'll do some research on an 'add-on' filter. Sounds like an interesting idea.

....and now for a completely different idea.
You may have see the pic of the rear wall. The drywall is about 9" from the concrete foundation wall, due to the upstairs 4" sewer pipe running across the wall. I didn't want "the ugly box" that a lot of basements have that incase HVAC and plumbing. Soooo, I brought the wall out. The point to all this is, ... IB. Is it feasible? Is it feasible with my drivers?

I've seen the radical set-ups on the infenitly baffled site. Neat ideas

Bob
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Adrian D.
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Re: hz numbers on a 15" 2 driver
Reply #132 - 05/19/06 at 17:28:56
 
60, i'd say 2 rl-p 15s.
amp gain@40% doesn't mean the subs are seeing 40% of the power.
one funny thing i noticed on my sub-amp: the x-over has power indicators (these are based upon input sensitivity) and the lower the bass goes the more power the sub is getting. gains untouched. it could be the weird headphone out i use as a pre-amp.
but the thing is that the lower you go down in hz, the more the subs have to move to produce the same spl. 8 mm xmax is pretty limiting.
i agree with john, because lowering the tuning will help. but only untill you will play something below tuning...
sealed could be the best option.  
the subs have to have high-ish qts to use in IB.
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« Last Edit: 05/19/06 at 17:40:05 by adi_ro »  
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #133 - 05/19/06 at 18:02:19
 
[quote author=Adrian D.  link=1145573673/120#133 date=1148056136]the lower the bass goes the more power the sub is getting. gains untouched. [/quote]

Well Adrian, That seems pretty obvious now that I see it in writing. I'm fairly dissapointed, and embarassed in myself for not realizing that. Several hundred watts at 100hz is much easier than at 25hz. Thanks for the reality check. That's why you received that A- !

Bob
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #134 - 05/19/06 at 19:03:00
 
[quote author=Bob  link=1145573673/120#132 date=1148053638]

Hey 60, a 10.6 lb magnet, OMG! 3 inches Xmas, OMG!!! that's cool, but they arn't very forthcoming with prices are they?



Bob [/quote]

but you dont get high end per..... really high end perfromance from an entry level sub.$120,000 cars are just that much better than $12,000 cars. sure crazy subs are expensive, but they will give you what you looking for.all the time you invest with 2x4s and drywall etc, thats all worth money isnt it? i say build a hwk the way steve designed it, and throw a pair of serious subs in there, then you get to sit back and enjoy.on the other hand my e bay $40 pair of old skool 15" jbls can fill my garden with enough bass to make me feel quite ill after a few hours Roll Eyes i have used ib installs before and as far as im concerend, the hwk gets as low as any ib stall ive ever used.
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Adrian D.
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Re: hz numbers on a 15" 2 driver
Reply #135 - 05/19/06 at 19:18:06
 
[quote author=Bob  link=1145573673/120#134 date=1148058139]

Well Adrian, That seems pretty obvious now that I see it in writing. I'm fairly dissapointed, and embarassed in myself for not realizing that. Several hundred watts at 100hz is much easier than at 25hz. Thanks for the reality check. That's why you received that A- !

Bob [/quote]
rotfl, i've topped my previous scores on all exams this year. i couldn't believe it.
hmm, i never applied anything i learnt in school, except maths
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #136 - 05/19/06 at 19:48:39
 
Bob,

Don't buy into the hype.  Your 2 drivers will almost equal the performance of one of those 15s that cost so much that they are afraid to post the price.  If you had a 3rd driver, you could out perform it.  

If your amp doesn't have a LF protection filter (rumble filter), then it's really not something to worry about now because you have to know what your final setup is first.  ie at what frequency you need it and whether you need one or two and how your drivers will be wired.  You have to know the ohms and hertz, for the correct filter.
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #137 - 05/19/06 at 19:54:18
 
60, Good bass from a couple of used 15"ers outside is different from <20hz in a movie soundtrack though, don't ya think?  I'll never say the HWK doesn't crank. Ever. It'll knock your socks off with a good source for music, no doubt about it. Steve has a helluva design there.

It just won't go low enough, loud enough on movie soundtracks for psycho's like me.

The IB thing was a passing thought/daydream. Not something I had my heart set on.

I do know the difference between a Ferrari and a Yugo, but I've seen too many 'hotrodders' that can build a rod that would keep the Ferrari looking nervously in the mirrors for a fraction the price. (That's where I want to be, I'm just having a hard time getting there.)  :)

Bob
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #138 - 05/19/06 at 19:56:47
 
[quote author=John in CR  link=1145573673/135#137 date=1148064519]Bob,

Don't buy into the hype.  Your 2 drivers will almost equal the performance of one of those 15s that cost so much that they are afraid to post the price.  If you had a 3rd driver, you could out perform it.  

If your amp doesn't have a LF protection filter (rumble filter), then it's really not something to worry about now because you have to know what your final setup is first.  ie at what frequency you need it and whether you need one or two and how your drivers will be wired.  You have to know the ohms and hertz, for the correct filter. [/quote]

Understood John.  ;)

Bob

P.s. No, it does'nt have a filter.
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« Last Edit: 05/19/06 at 19:57:48 by Bob »  
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #139 - 05/19/06 at 20:24:02
 
bob...and john,
forgive me for flogging a dead horse but, if bobs drivers are bottoming out, doesnt that mean they have reached the end of their capability, and to get 'more' you either need more drivers or a 'better' driver? bob have you tried just a straight sealed box? apparently the roll of down low is 'best' in a sealed enclosure, also the subs might be able to handle more power? just a thought. personally i would have thought a pair of daytons and 900 watts would be more than adequate for watching a movie? cant imagine what your trying to achieve Roll Eyes tyranosaurus rex @ realistic levels would require a 30 ton creature jumping up and down outside your door.i wont comment further, john is way more qualified to asist you than i am. but i do believe some of the 'hype' those beastly subs sure do pack some punch. Grin
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #140 - 05/19/06 at 20:45:51
 
[quote author=Bob  link=1145573673/135#138 date=1148064858]60, Good bass from a couple of used 15"ers outside is different from <20hz in a movie soundtrack though, don't ya think?   [/quote]

i have tested my hwk with a test disk and had useable output
below 20hz with my e bay jbls
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J_Rock
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Re: hz numbers on a 15" 2 driver
Reply #141 - 05/19/06 at 21:25:15
 
Bob's drivers are fine.  The HWK is not a LFE sub.

The HWK design ports at higher frequencies for the CLUB bass its meant to be used for.  Below these frequencies the enclosure does little to curve the driver's movements.  Hence the bottoming out.

Those DD audio subs will nto work for HT, a FS of 32Hz makes them unusable for sub-bass frequencies.

The Rlp subs might work, but again I do not believe in their SQ.

So John is absolutely right in sticking with your series 2 woofers.  They have a low Fs and a decent power handling.  Not that Power is that much these days.  Linear throw is what will determine the viability of any woofer for sub bass frequencies, 2 15s with 12 mm xmax or 24 mm of travel will move plenty of air.

With that said, John is again right in his thinking.  I just differ slightly in that I believe you need to get out of the moding HWK scene and start over.  There are many different options to explore:

~Low Tuned Horns - Although Huge they are my favorite type of Bass
~Transmission Lines - The main objective of these enclosures are as "Bass Enhancing devices."
~Low Tuned Large Boxes (Notice "boxeS"  Stereo subs for better room node excitiation.)


I think Bob really needs to step away from the ISO config though.  HT is all about air movement, ISO halves his capability when compared to 2 seperate 15s.  The only gain being a smaller enclosure and decrease in even order distortion due to suspension non linearities (Which I suspect these daytons have few to begin with).

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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #142 - 05/19/06 at 21:35:12
 
[quote author=J_Rock  link=1145573673/135#142 date=1148070315]Bob's drivers are fine.  The HWK is not a LFE sub.

The HWK design ports at higher frequencies for the CLUB bass its meant to be used for.  Below these frequencies the enclosure does little to curve the driver's movements.  Hence the bottoming out.

[/quote]

so what freqencies are we talking about? if my car sub plays flat-ish from 80 down to 20, LFE frequencies are how far below that? 19, 18, 12,?? and how much imformation is on the movie recording that low?

is there a significant difference between music lows and movie lows? does bob need 2 seperate subs, 1 specifically for movies and another for music?
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #143 - 05/19/06 at 21:38:58
 
Responses range from narrow bandwidth to wide bandwidth with typical responses down to 13 HZ on all three models. Box can be built for 8's,10's, 12's, 15's or 18 inch woofers.  Note: The design is for a 15, however the the box can be scaled down (and so the performance) to smaller drivers but you will have to specifically tune anything below the original 15" design.
Using musical instrument woofers (ex. PEAVEY BLACK WIDOW) you get tight full accurate bass from 200 down to 40 HZ. Using subwoofers you get big warm full bass that can on command create Subsonic pressures lower than 20 cycles.  


thats a quote from decwares hwk page. i believe the hwk IS able to produce very serious low bass.how much lower than 13 hz do we want to go?
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« Last Edit: 05/19/06 at 21:39:32 by 60ndown »  
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #144 - 05/19/06 at 21:50:19
 
Check reply #22 and #28 on page 2.

Bob
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« Last Edit: 05/19/06 at 22:12:01 by Bob »  
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #145 - 05/19/06 at 22:02:46
 
60, If I understand correctly, drivers (cone travel distance) can be controlled by how much air is allowed in and out of the enclosure.

Playing with airflow restriction is a form of "brakes"/"shocks" for the drivers, changing the max cone travel.

So if this is true, to continue the automotive analogy, it would be like antilock brakes, or traction control. The system allows life to happen "as it will", until it see's something it doesn't like, then it interveens [sp] and reigns it back in just before bad things happen (tires lock up, tires spin, driver/cone bottoms out)

.....or, this could be complete bullshit. Please correct me if I'm wrong.   Wink

Bob
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #146 - 05/19/06 at 22:07:44
 
[quote author=John in CR  link=1145573673/15#28 date=1146245146]Bob,
 The HWK is not an HT subwoofer.  It is a great club cab though.  It simply doesn't do low enough to be good for HT.  As stated above, it was designed to roll off below 40hz.   [/quote]

hmm so who do we believe john or steve? 40hz or 13 ???
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #147 - 05/19/06 at 22:12:28
 
I don't have any means of measuring hz, but this thing is not getting NEAR that low. I've played sweeps a few months ago from 150hz, down to, ummm..... 20?.. 25???
Sweep, or more like 'steps' when one hz at a time. They trailed off badly, almost got QUIET below,.... umm, 40hz? Just about the time things started getting GOOOOODDD.


Bob

(I believe my ears)

I need to run the sweeps again, just for 'grins'.
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« Last Edit: 05/19/06 at 22:13:07 by Bob »  
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #148 - 05/19/06 at 22:22:25
 
call steve on the phone and ask him what the best way to implement the hwk into a ht system is.
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #149 - 05/19/06 at 22:47:58
 
60,

I appreciate your enthusiasm, but the HWK is not at HT sub.  In the good sounding aligment making use of the big iso chamber, the upper chamber (lowest tuned one) of the 15" version of the normal HWK is tuned to about 45hz.  If you put the driver(s) in the bottom baffle only (unbalanced sounding IME), the top is only tuned to about 35hz.  The alignment definitely allows for extension below port tuning, but none of the driver arrangements are going to give any kind of significant performance in the teens no matter what driver you put in them.  The HWK is for music.

With Bob's current configuration, the big chamber is tuned to about 19hz, and with the magnet in the top chamber and the cap on, it is tuned to about 47hz.  Bob, now that I've put the calculator to it, you should test the SQ and limits like this, call it the HWK-HT.  If you want to try 15hz tuning, you need to add another 10" to that 13.5" port OR you could leave the vent the same and mount the drivers as the top cap (14-16hz tuning).

Bob, if you can make the 6th order bandpass (ports top and bottom) work for you SQ and extension wise, that's probably your best easy thing to do, since the top chamber helps control excursion below tuning better than the ported alignment (driver open to the room).  

Put the top cap back on and try to integrate it with your mains and play some of those LFE tracks.  You may have gotten lucky and be done for now, at least until you build some new mains.
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