Here is a site that shows the pin out of wire for making the cables.

http://www.mediacollege.com/audio/connection/

One more thing - given the option between a balanced or unbalanced version of a given cable, you probably want to use the balanced version.  The discrepancy arises because RCA is inherently a single-ended connector (i.e. 2 conductors as opposed to XLR's 3).  The potential for the chassis grounds of source and amplifier to float with respect to each other can lead to amplifier hum, for example.

Balancing may not be important in Bob's home theater, but there are other pragmatic reasons for using the XLR connections - maybe more important for PA applications than for use in the home, but still worth mentioning:

1) the XLR engages all of its conductors at once, and can not short circuit the signal lines during connection / disconnection

2) the XLR is a positive locking connector

Just a thought - if the amp has both XLR and 1/4" phone plug inputs, could you achieve the split by using a single RCA to XLR from the receiver to one amp input, and then use a 1/4" phone plug jumper between the two input jacks on the amp?

cabbies in romania don't carry guns...or at least i haven't met any
come by anytime
the stuff about xlr and other types is really useful. thanks for the topic guys. i hope bob uses this info

Actually I purchaced the LSA900 here.... http://stores.channeladvisor.com/musicsupplycenter/Items/100-01-0208?

But, I'm sure the inputs/outputs would be the same.

Bob

15" for sure. Total size of the box you'll stare at isn't a big difference. Driver price difference not much. Have you read the entire thread? I got the Dayton Series II's from parts express for $88 each. Think it might be pretty cool.

Bob

Bob, I have a 15" peavey black widow laying around and 3 JL 10W3s. That is why I have to decide. But as you said I am leaning toward the 15" and later buying some Dayton's.  

It sounds like confusion is all, the LSA 800 says it uses 900 watts worth of transitors. Perhaps this is the mistake.

Either way, The amp will work fine for those daytons.  

You could do either XLR or 1/4 inch, the only reason I suggested XLR is for the Postive locking.

Ok, I lied. I did taxes this week end, Forgot about those.   NEXT weekend I've got a 3 day weekend. Plenty of time to build A HWK. None of my new toys came yet.  >:(

Bob

[quote author=Bob  link=1137542099/60#65 date=1137795213]Here's what Music Supply Center calls it... http://stores.channeladvisor.com/musicsupplycenter/Items/700-05-0006?

As far as the difference in connector / termination, I also like the idea of the XLR. The 1/4" reminds me of the 1/8" stereo plugs that you would here static until you rotate the plug... not what I need.

Bob [/quote]

I'm not quite sure where the notion came from that you will be immune to those problems simply by using an XLR connector. Pros using that amp may have to set it up in 4 or 5 different locations every week and put more wear and tear on every connection than you will at home.

There are many reasons to use an XLR, but the reasons stated for not using 1/4" is mainly encountered when using an amatuer grade connector. If your amp has high quality jacks and you buy pro quality plugs, you won't experience any static or degradation in the signal transfer. The shorting of the output can become a concern with certain tube outs, but generally you don't want to hot swap audio gear any way. Develope good habits from the beginning regarding your new amp.

Glad to see it coming together for you. Keep us posted!

[quote author=Bob  link=1137542099/60#69 date=1138194607]
When you say develop good habits with my amp, are you refering to hot swapping?

Bob [/quote]
Yep!
I watched as a friend once tried switching stuff around and before I could stop him, the speaker outs from 2 different amps touched [LIGHTNING] and it fried both his new amps. He was not practicing "Safety First" as they say.

[quote author=Bob  link=1137542099/60#71 date=1138198356]  :o  :o
Not a happy camper......
Thanks, that is a practice I should start.  I've been known to yank S-video, and component cables while equipment was on.  BAAAD!! Stop it....

Bob [/quote]
I don't know much about the mechanics of video, but I know many of the circuits are assembled in static free clean rooms because some of the chips used in that gear have microscopic conductors that are sensitive even to static electrical discharge that we couldn't feel. I'm sure the supporting circuitry helps to protect it to some degree, but I prefer not to temp or dare The Devil.

Quick question, in a dual driver HWK, I'm thinking about mounting the top driver face up (magnet down in center chamber). Do I set driver in hole from the top chamber, resting it on the back side of the driver flange with gasket. Or, do I install in center chamber FROM the center chamber, so the built in gasket is against the bottom of the top divider.

Or does it matter.

Reason is, ease if installation, holding the driver with one hand trying to install fasteners with other hand. Easier to just set it in hole.

Bob

Not a bad idea about the putty. In the automotive industry we use a material we call 'dum dum'. It's about 1/4" - 3/8" diameter 'rope' that comes in a roll. Black and gooey used to seal HVAC in cars. I think our parts department has some.   ???

I'm thinking I'll make one entire side removeable to ease in driver musical chairs. Will probably design some overbuilt PITA as a gasket. Thought about a 48" piano hinge to make almost a closet door type setup. You've seen the pins racecars have to hold the hoods on, that would be the latch. Would require extensive gasketing, almost like a refrigerator. Somehow keep gasket in place during use.  No, .... I won't call fridgedaire and ask the spl rating of the fridge gasket.  ::)

Bob

Yea, "Camper tape". much easier to work with.
Bob

Of course, Sean is right, but I was thinking we had gone past reality and were engaged in thought play at this point. At least that's what I got from your hinge idea.

If you're worried that it will take a long time to decide which "tuning" you prefer, don't. You have 2 drivers, right? You also have 2 ports and 2 chambers, the center one doesn't make sound so it doesn't count.

Placing them with the magnets in the center chamber will give you the lowest tuning in both ports.

Placing them with the magnets in the vented chambers will give you the highest tuning in both ports

Both of those arrangements will give you a push-pull loading with the drivers firing in opposite directions and result in the least non-linearity distortion. Either way I would wire them electrically out of phase with each other so that they work in unison...... both helping each other.

You can also place the drivers with both magnets down, push-pull. This will give you the lowest tuning on the low port and the highest tuning on the high port. In other words the widest bandwidth box.

Reversing them and placing both magnets up gives you the narrowest bandwidth.

I prefer the lowest overall tuning.

Try Tools / Internet Options / "delete temporary files" (delete all offline content)...... "delete cookies". You might make sure your browser checks for newer versons of stored pages under settings, also. That stuff becomes corrupt sometimes if you use Windows.

The only caution is for other sites you visit that log you in automatically using cookies. You will have to log in to everything again.

I have found that this site dumps you off at odd times or when you least expect it, especially if you refresh a page it many times logs you off as part of the command. Security reasons, I guess.

now about the magnets in center chamber : there would be another advantage besides lower tuning. the cones will couple together better and improve linearity because it's sort of an isobaric loading

"ISOBARIC LOADING" is a term I've heard many times, not very sure of the meaning.

Dowel rod sounds like a very good idea, but the Daytons I have, have a hole in the center covered with a screen. Don't know how I'd attach the rod.

Bob

That funny hole is necessary for cooling the voice coil. Don't block it! You could still have the same bracing by using a flat board with a "U" shape cut out of the ends. Make the U bigger than the hole and it won't impede the airflow.

"Isobaric" refers to pressure or more precisely, equal pressure. When you put 2 drivers together and make them work as one, the pressure between them remains equal on one side of the motor and aided by the other motor and cone, gain a little bit a stability from the "loading". Two motors working as one, coupled with an equal(izing) pressure chamber in between is stronger than one motor.

Many people will say it's a waste of a good driver and that one driver alone will be just as good. They would be correct as far as the first half, or so, of the drivers operating capability goes.

It's when you really need to lean on the drivers that the benefit from iso-loading becomes apparent. When really pushed, the double motors are more stable and resist over-excursion better than one single driver alone can.

In addition to all that, when you have them facing each other and they work as one unit, any non-linear distortion will be averaged and theoretically reduced to one half. Non-linearity is caused from a driver moving in one direction with a different compliance, or restance to movement, than it moves in the other direction. If it moves out easier than it moves in, or vice versa, you have a problem ...... a very common problem.

Obviously the volume change ahead of the woofer must be equal to the volume change behind it, so from that perspective there is no difference between mounting a woofer magnet in or magnet out; however, compliance differences will occur as a result of the cone surround and spider geometry.  For example, a rubber surround which is a half-circle cross section will not deform the same way when the cone moves out versus in - the non linearities are slight in a well designed driver, but for a matched pair of drivers, isobaric mounting averages the non-linearities in each direction so the effective compliance is the same regardless of the direction of cone movement.  Where mounting direction matters is when using drivers as direct radiators, as opposed to in bandpass or horn loaded enclosures, since the shape of the driver cone affects how the sound disperses, and having a metal basket and motor assembly right in front of your driver is obviously going to be detrimental from that perspective.

i also noticed the quality of the bass the hwk produces was much better than i thought it would be. you might find you get more of the 'car audio' bass in your chest effect with 'different placement' i suppose your level of happiness will be dependant on what you prefer, 'bass in chest' or lots of 'quality bass in room', if you find your un happy with the hwk in a few weeks just buy a good 10 in sub and strap it too your chest dureing playback! seriously try the hwk in different locations in the room. and that amp of yours would drive me nuts! as loud as a microwave?  its gotta go back.

[quote author=Bob  link=1137542099/90#91 date=1138628457]Happy Monday morning.

Hwk is finished except for cosmetics.


But you don't get the "punch in the chest" I was hoping for. Quality of sound is excellent. Needs more tweaking with settings though. Bob

p.s. Have I said how big it is?
[/quote]

You built a subwoofer that wears make-up?

Hi, Bob,

Punch in the chest is not really bass, and LFE is not really about punch. I may have misguided you if you want "punch". I recommended to place your drivers in the lowest tuning, which would take away some punch and give you more gut disruptive pressure effects. All that stuff moving around and rattling is a sign that something is happening that's powerful.

Before you go too far tuning I would live with it for a few days and get used to what it does with many different programs and goof with the placement a little.

You will find that moving the cabinet will have quite an effect on the output, even turning it in the same spot can change everything. After getting tired of moving it around, you can try changing the way the drivers mount inside to re-tune it to a (higher if you want more punch) range you like better.

Another point to take into account before you do any tuning at all is that the drivers need to break-in a little. So, for your new drivers I suggest you just play them for a few days and see what happens, then change stuff, one thing at a time, to improve your experience.

As far as your amp goes, chech to see if there is a "speed" switch on the fans. That light is designed to be OBVIOUS in a smoky room up to 100' or more away. You can always put tape over it. I like to use some of that make-up you mentioned earlier. After I'm satisfied I won't need warranty service I use nail polish to hide those annoying lights, but don't tell anyone.

[quote author=Bob  link=1137542099/90#95 date=1138635679]. Are you saying it's a trade off between VERY low hz, and the 'feeling' I'm wanting?

Bob [/quote]

no  :-X, its the difference between what it 'should' sound like and what it 'does' sound like. a dinosaur takeing a step 100 feet away would have a very distinct sound, as does a hammond organ and a fender precision bass.the idea is to set up our rigs, so they reproduce "faithfully" the origional sound.trouble is with so many subwoofers is that you would not be able to tell what kind of instrument it was, or exactly how heavy the creature is, because EVERYTHING SOUNDS EXACTLY THE PHUKING THE SAME. its very exciteing to have a sub that will make it obvious when your listening to a bass guitar or human hands drumming on a table  ;D  set all your gains to FLAT. put on a very familiar disk (music) play at medium levels and adjust sub amp until it feels / sounds good in the main listening seat.no bass boost, no loudness, no eq no nada, just a clean signal amplified well and into the hwk! when set up like this the onlything you should ever have to adjust is the 'level or volume' of the sub. if something your playing sounds dryer or sloppyer or harder or deeper its because its 'recorded' that way, and the fact that you can hear the difference is a good thing

60, DirtDawg,   I respect that very much. My goal is quality, always has been. I'll never change that. Nothing better than to sit in a perfectly quiet room listening to well recorded music on a decent system. A religious experience all in itself.  But, the main goal of this system (95%) is for home theater. So when that dinosaur takes a step, I want to feel it too. I mean a nice solid rumble in my chair. When that rocket takes off or the volcano blows, I want more rumble. But occasionally in a movie sound track, it may be necessary to have even more.

Here's what been in the back of my mind, almost since I started building this room.   I was in the listening room at Ultimate Electronics watching a demo of a front projection setup. I started paying more attention to the sub, because you could feel it (in a tactful way) when it was necessary to feel it. After watching for awhile, I got up and looked at the price, $1600.00.  Not on my budget for a sub. So I started down the DIY road. I figured I was half way there, I've got woodworking skills, just don't know crap about how to turn a bare driver into a religious experience, ...... an art form.

DirtDawg, refering back to your signature, I would replace 'music' with 'movie'. It's an escape from reality, a drug.

As far as the test tones go, No, I wasn't listening to them pretending to know what I was doing. My point was to listen to some audio tracks that had a LOT a bass. These are tracks that the car audio guys use during competition. All spl's and db's. Not my listening preference. Just playing with my new toy.... Some of the disks had tones too, so I was more, "playing" with them, than anything else.