Subwoofer driver buy-in poll - Page 8 - Home Theater Forum and Systems - HomeTheaterShack.com
View Poll Results: Which drivers would you like to see being tested AND could chip in to make it happen?
Ascendant Audio Avalanche 18 8 15.09%
Sound Splinter RL-p15/18 31 58.49%
Fi Q15/18 15 28.30%
Mach5Audio IXL-18.4 9 16.98%
Dayton RSS390HF/HO 12 22.64%
Something else? (post it) 11 20.75%
Multiple Choice Poll. Voters: 53. You may not vote on this poll

 
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post #71 of 96 Old 01-30-08, 01:18 PM
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Scott
 
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Re: Subwoofer driver buy-in poll

600 liters tuned to 15hz with a 10 inch port look great to me.


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post #72 of 96 Old 02-02-08, 01:38 AM Thread Starter
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Re: Subwoofer driver buy-in poll

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vinculum wrote: View Post
Itay is correct. The higher Fo of 28.2 Hz makes the porting favor an approx. 20 Hz tune. The 15 is a little lower at 24 Hz.

Dr V
It's not just the Fs that dictates the best possible tuning frequency. You have to look the shape of the frequency response too. You don't want to create a recession just above the tuning or peak at the tuning.
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post #73 of 96 Old 02-05-08, 05:20 AM
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Re: Subwoofer driver buy-in poll

I'm more interested in seeing the 18" Acoupower tested in a sealed box than ported, or will you do both?

I also don't understand Carlos' not wanting to give the commonly xmax spec of 70% BL, or why it would be unKlippelable".

He could just give the value of 10% THD which is supposed to roughly correspond to 70% BL.

Or Ilkka could tell him when he measures them.

Last edited by noah katz; 02-05-08 at 02:26 PM.
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post #74 of 96 Old 02-06-08, 01:49 AM
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Re: Subwoofer driver buy-in poll

The Acoupower 15" was measured in Voice Coil magazine a while back including Klippel data. I can dig it up and post it (the Klippel data), if there is interest, or maybe Carlos has the reprint rights. In my experience, due to the statistical nature of the Klippel test and the limited number of data points at the extremes, the results need to be taken with a small grain of salt. At least the suspension and BL we well balanced (with neither being a huge limiting factor) and so the data is more "real" that it would be if that weren't the case.

IIRC, Xmax was in the 28 mm range with near perfect suspension symmetry and centering. This is particularly impressive because of the spider being a 6" ID and 12" OD.

Last edited by Chris Brunhaver; 02-06-08 at 03:11 AM.
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post #75 of 96 Old 02-06-08, 02:56 AM
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Re: Subwoofer driver buy-in poll

Quote:
Chris Brunhaver wrote: View Post
The Acoupower 15" was measured in Voice Coil magazine a while back including Klippel data. I can dig it up and post it 9the Klippel data), if there is interest, or maybe Carlos has the reprint rights. In my experience, due to the statistical nature of the Klippel test and the limited number of data points at the extremes, the results need to be taken with a small grain of salt. At least the suspension and BL we well balanced (with neither being a huge limiting factor) and so the data is more "real" that it would be if that we're the case.

IIRC, Xmax was in the 28 mm range with near perfect suspension symmetry and centering. This is particularly impressive because of the spider being a 6" ID and 12" OD.
Yes, We want a copy of that. If you can't post it here, I'll PM my email address!

Dr V
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post #76 of 96 Old 02-06-08, 12:52 PM
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Re: Subwoofer driver buy-in poll

Attached are the T/S parameters and Klippel data from the review. I'm not an expert in copyright law so if the mods need to take it down, I respect that.

The editorialize a bit, obviously with an 18.25 mm "underhang" and a long coil the driver has very linear BL and due to using a 6" diameter 2-layer coil and copper sleeve on the has very high power handling and good low Le, good Xmax etc.

I know that drivers like this and the LMS TC sounds stuff capture the imagination of DIYers but I think that people are missing the point a bit. With the research that has been done by Harman and others showing how multiple LF sources having a very positive impact in smoothing rooms modal responses, the question isn't who can build the best $1k woofer, unless you have a lot of money to build 4 of them. Instead, four $250 woofers would be a better bet for that $1k budget. As engineering is really the art of doing the most with the least (and furthermore fits within the demands of the application from all other factors therein) these brute force approaches are not that interesting to me personally.
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post #77 of 96 Old 02-06-08, 01:48 PM
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Re: Subwoofer driver buy-in poll

The data looks pretty good to me.
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post #78 of 96 Old 02-06-08, 01:51 PM
 
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Re: Subwoofer driver buy-in poll

Quote:
Chris Brunhaver wrote: View Post
I know that drivers like this and the LMS TC sounds stuff capture the imagination of DIYers but I think that people are missing the point a bit. With the research that has been done by Harman and others showing how multiple LF sources having a very positive impact in smoothing rooms modal responses, the question isn't who can build the best $1k woofer, unless you have a lot of money to build 4 of them. Instead, four $250 woofers would be a better bet for that $1k budget. As engineering is really the art of doing the most with the least (and furthermore fits within the demands of the application from all other factors therein) these brute force approaches are not that interesting to me personally.
I completely agree with you on this one. Also, the Infinity Kappa Perfect/VQ series is a perfect high quality budget option for such a situation. Eventually I will have four of them in use for movies and two in stereo use for 2-channel listening.

The thing is raw power just seems so much cooler than a bunch of "little" subs.
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post #79 of 96 Old 02-06-08, 02:46 PM
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Re: Subwoofer driver buy-in poll

We're just evaluating the driver here, not a bass system. If you have $1000 to spend and your goal is value based, then Acoupower isn't the best bang for the buck. Four lower cost drivers would then make the most sense. I have 2 of these Acoupower 18" drivers which will be non co-located. I'm not really on a budget so, I'd have no problem getting 2 more if needed.

Chris, thanks for sharing that data. I was also expecting an article to go along with it. If there is one, could you include that?

Thanks!
Dr V
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post #80 of 96 Old 02-06-08, 10:55 PM
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Re: Subwoofer driver buy-in poll

There are many ways to energize a listening area with low frequency power. I'm among those who like to see it done with just a couple drivers in smaller boxes. To do that requires special build qualities and design techniques using special materials and a person with a unique personal drive to keep advancing the technology. Acoupower is one of those special drivers.
Sub drivers more than mid range or tweeters peak my interest, kinda like other things that fit formulas IE: 12 oz. Bud Light, Dbl quarter pounder w/cheese, 36-24-36, Corvette Z06, etc.
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