Welcome, Guest. Please Login or Register
Decware Audio Forums
10/22/14 at 15:10:34


Pages: 1 2 3 4 
Send Topic Print
Oh boy.... I really started something..... (Read 13524 times)
VexorgTR
Ex Member



Re: Oh boy.... I really started something.....
Reply #15 - 05/23/06 at 04:03:34
 
I really am not trying to start a war....  my points are...

#1.....  I think the Imperial as a Theatre speaker would be cool.....  

#2.... So far the Bill F speakers I've built have done better than the off the shelf units...

#3...  Bill F Says the Jensen is not worth persuing... and it's just plain old news....

#4.... There must be something to the imperial,  but the only person who really raved about the full range is Steve...  the SO version is getting a nice buzz,  but again,  I'm thinking Theatre speaker....    Full range,  major dispersion....


I am digging for some serious thoughts from some serious listeners.......... and I'm trying to avoid illogical ideas and concepts.

I know that many a time I come off as a bit cold and blunt...
Then again, I'm sort of annoyed that the Jensen Imperial is being sold here as a one size fits all...  and it's too friggn big for a bedroom,  way to friggn big for a car....   you get the idea.   If I build a pair,  I want them to sound big, and clear... I plan to donate them to a very sizeable church.
Back to top
 
 
  IP Logged
AAFRadio
Ex Member



Re: Oh boy.... I really started something.....
Reply #16 - 05/23/06 at 11:57:28
 
Every now and then I check in to see what's going on and saw this thread on wide range Imperials.  I've built more than one set of these speakers over the years, the latest set with additional bracing similar to Steve's SO design that was not in the original plans.  Coming from both an EE and orchestral concertmaster background, I would underline Steve's caution about determining your application as absolutely critical.  I wouldn't build the SO because I have no interest in music that goes below 30Hz, the 5db down point with the original lab design at left.  For those who do, and want a boost in SPL at the lower end, more power to you!   Grin  That kind of boost just doesn't sound like what I hear sitting on the stage in a large orchestra and being a part of recreating a classical piece of music.  Like every one of you, I've listened to a lot of speaker designs, and can only say that for orchestral and pipe organ program material, the original design using the G-610 is still hard to beat.  You won't get the bass you feel with the SO's, but you won't hear that in the concert hall, either.

Unfortunately, there are so many variables that it is almost essential to hear a pair in your listening environment and with your kind of music.  Those variables can range all the way from the equivalent of a dummy load in antenna terms (Imperial in a van) to an infinite impedance load (an open field) and all the classic transmission line matching equations and techniques (in sonic equivalents) apply here.

Best wishes,
Mike

Back to top
 
« Last Edit: 05/23/06 at 13:05:39 by AAFRadio »  
  IP Logged
Mr Content
Ex Member



Re: Oh boy.... I really started something.....
Reply #17 - 05/23/06 at 12:35:59
 
Interesting observation Mike, and I suppose its true from your stand point. I listen to a lot of different music, and classical is not big these days, I have a lot vinyl classical music, but CD's dont seem to have the dynamic range to do the music justice. I do like a good sub for other genr'es of music though. But I get what you were saying, get what fits. Smiley

Mr C
Back to top
 
 
  IP Logged
Gexter
Ex Member



Re: Oh boy.... I really started something.....
Reply #18 - 05/23/06 at 13:08:45
 
Get what fits is the best advice.
sometime you really have to take a look at the room, the music, and what you wanna hear in it.
Then make a leap by what people with the same tastes in music say about it. Can't say any one speaker will last to your dying day for most. tastes changes
Sometimes even a speaker that you look at and say " boy I like those" after all the other needs are met.
Back to top
 
 
  IP Logged
BIG_GEOFF
Ex Member



Re: Oh boy.... I really started something.....
Reply #19 - 05/23/06 at 21:38:31
 
VexorgTR wrote Quote:
Then again, I'm sort of annoyed that the Jensen Imperial is being sold here as a one size fits all...  and it's too friggn big for a bedroom,  way to friggn big for a car....   you get the idea.


I feel like you're taking one small idea, and basing your entire assumption about the imperial thread off of one idea.  When was it ever wrong to throw around an idea?  Many of the threads in this forum are specific to ideas but there are always some that are a little out there, and i tip my hat off to those who like to defy logic or think up what some would concider ludacris ideas.  
  VexorgTR I'm annoyed, that you come in to a forum, and "get annoyed" at one thread and sort of put the entire forum down because of that.  Yes, the imperial in a car doesn't sound like a good idea, but have you tried it?  Many a times things happen when they shouldn't and who knows, it could sound great.  
     The last time i checked, there were 150 subjects posted in the Imperial forum, and you shun the forum for 1 subject? You you came here looking for ideas and  say Quote:
I am digging for some serious thoughts from some serious listeners.......... and I'm trying to avoid illogical ideas and concepts.
, i believe you are disrespecting many members here, myself included, who may say an "illogical idea" but that is because my lack of knowledge of speakers.(i had my imperial in my bedroom for about 2 months before i moved it to the basement, it sounded great to me)  Many like to push the envelope.  So please, respect the members of this forum and their Quote:
Illogical Ideas


-Geoff
Back to top
 
 
  IP Logged
shayneyasinski
Ex Member



Re: Oh boy.... I really started something.....
Reply #20 - 05/23/06 at 22:05:35
 
just one other thing i have learned.
take 1 box and lode it with a 15 and a horn then listen to it .
then take what you just listened to and go to a school then a bus stop and so on.
it will in most cases always sound different just like any design from here or any other site.
for a test i built a 4 ft cube box and made plates for different drivers and also ports that i could cover and open.
then i used a small powered sub amp and x over that you would find in a store bought powered sub.
now i did this so i could better understand speaker specs and WOW they are alot of thing i found out.
my first test was with an 8 inch driver i had from mcm in the box with no port i could drive it to where it would pop but there was no audible sound of bass.
so i uncovered a port and instantly BOOM BOOM BOOM .
I did this with 9 other drivers and all were differnt.
so my point???
you may have a killer box and a killer driver but maybe not a killer match.

happy building.

shayne
Back to top
 
 
  IP Logged
Lee in Arkansas
Ex Member



Re: Oh boy.... I really started something.....
Reply #21 - 05/24/06 at 12:56:42
 
Can someone clarify this for me? (Quoted directly from Bill Fitzmaurice)
Quote:
If you put two 8-ohm drivers parallel wired in one double-wide box the impedance must remain 6 ohms. Since the electrical impedance is 4 ohms the air column is only adding 2 ohms to the load. That makes perfect sense, as using two drivers instead of one does not result in 3dB higher sensitivity.

Since the sensitivity with two drivers is the same as with one that means that the resisitive load of the box is halved. If it remained the same then the second driver should cause a 3dB sensitivity increase, and it does not. Think of the second driver as a sponge that soaks up half of the acoustic impedance.


Maybe I'm just uneducated, but I thought doubling the drivers gave you a 3db increase, all other factors the same?
Back to top
 
 
  IP Logged
VexorgTR
Ex Member



Re: Oh boy.... I really started something.....
Reply #22 - 05/24/06 at 14:19:39
 
Relax Geoff.... As I figured,  you're reading into things way too much.   It's sort of like how Al Sharpton finds racism in everything.   Just wanted to keep everything on this thread on a serious note.

I'm getting close to making my next builds.....  I'm thinking about driver selections, and making it a 3 way like the old one was.
Back to top
 
 
  IP Logged
Braggi
Ex Member



Re: Oh boy.... I really started something.....
Reply #23 - 05/24/06 at 15:40:59
 
[quote author=Lee in Arkansas  link=1148275933/15#21 date=1148471802]Can someone clarify this for me? (Quoted directly from Bill Fitzmaurice)

Maybe I'm just uneducated, but I thought doubling the drivers gave you a 3db increase, all other factors the same? [/quote]

I'm completely lost by the quote from Bill F.

That said, I think the 3db increase happens if you add another powered speaker box exactly the same as the original. That is, another speaker box and another amp.

If you double the drivers in a single box with the same amount of power you don't get 3db spl increase. What you get depends on many factors ...
Back to top
 
 
  IP Logged
Lee in Arkansas
Ex Member



Re: Oh boy.... I really started something.....
Reply #24 - 05/24/06 at 15:49:24
 
Adding a second speaker yields a 3db increase. Adding twice as much power yields a 3db increase. Adding a second speaker, and adding power to it(doubling the power of the channel) yields a 6db increase.
Back to top
 
 
  IP Logged
J_Rock
Ex Member



Re: Oh boy.... I really started something.....
Reply #25 - 05/24/06 at 23:19:58
 
He saying inside the same box, that the air becomes much more resisitive since 2 drivers are pulling on it.

Heres a better way to think about it.

In your 1 cu ft box, you have 1 10 inch subwoofer.  The subwoofer has an acoustical impedance of 8 ohms, and the air in this configuration adds 1 ohm of resistance. (Due to the change in volume when the cone moves back and forth.)
Total impedance of 8-9 ohms.

If you add a second sub exactly the same make, the acoustical impedance halves.  It is now 4 ohms.  The air inside the box will be pulled twice as hard, so the force on each driver, will be twice that of one driver, so 2 ohms.  Not to mention that 2 drivers experience it.  So a total of 4 ohms from the air is added.
Total impedance is again around 8 ohms.

So where does this 3 db increase come from?  Well in this case there would be no increase.  The same amount of power in no matter what.  So there can be no increase.

The 3db one would expect when adding another woofer is usually only when impedance is halved.  Hence a second identical subwoofer in its own enclosure wired in parrallel.  Half the impedance.  Twice the power goes to the sub, however the same amount as originally to each single sub.  3 db.

Its all good...
Back to top
 
 
  IP Logged
J_Rock
Ex Member



Re: Oh boy.... I really started something.....
Reply #26 - 05/24/06 at 23:21:40
 
Not to mention that quote is confusing as hell because he mixes up Acoustical and Resistive in the last paragrpah totally changeing the meaning...
Back to top
 
 
  IP Logged
Gexter
Ex Member



Re: Oh boy.... I really started something.....
Reply #27 - 05/25/06 at 00:41:14
 
doubling the drivers in the same box does not give you a 3 DB increase.

Or so I thought!
Not hard to check, I just am too lazy to wander away from this site or dig in the forums.

I would read the whole thing instead of part of it. sometimes something is not written well and confusing. I have heard the craziest stuff but thats not what was intended.
I write stuff I look back and say What was I thinking?

Now that I look back  " what was I thinking"

Gex the author of confusion.
Back to top
 
 
  IP Logged
boydon_lepasci
Ex Member



Re: Oh boy.... I really started something.....
Reply #28 - 05/25/06 at 01:01:56
 
The quote makes more sense if you understand the way a front-loaded horn works(as opposed to an Imperial). All sound from Bill F's designs comes from the horn; there is no direct radiation from the cone. Front-loaded horns have a much stronger influence than the T/S parameters of the driver. I have probably oversimplified this and I'm sure Bassboy and others will be helpful in expanding the concept.

As far as electrical impedance, if two drivers are splitting the power, do you really get 3dB increase? This is one of the most debated ideas I have seen over many forums. Doubling the cone area then splitting the same amount of power(one variable at a time), do you get an increase? Or do you have to give each speaker the amount that the single drive got?
Back to top
 
 
  IP Logged
JimP
Ex Member



Re: Oh boy.... I really started something.....
Reply #29 - 05/25/06 at 12:48:25
 
This is the way I understand it.  If you wire two identical 8 ohm speakers in parallel (let's say in 2 separate boxes to avoid that issue) then you end up with a 4 ohm load.  Your amp can generally deliver twice the power into 4 ohms compared to 8 so you end up with two speakers each getting the same amount of power as your original single 8 ohm speaker.

All else being equal, those 2 speakers together will give you a 3 db increase because each is playing just as loud as the original single speaker, but you are putting in twice the power.  There's no free lunch.

Jim P
Back to top
 
 
  IP Logged
Pages: 1 2 3 4 
Send Topic Print