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Author Topic: Prosound Shootout  (Read 32099 times)

Tom Danley

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Re: Prosound Shootout
« Reply #20 on: August 16, 2006, 09:52:33 AM »

Hi Guys, Wayne

Wayne, for the sake of the people here, lets put this in perspective.
First you argued against the Lab sub design approach,  the Math I used which wasn’t what you used and then took the position of "who needs it" in your posts.  A few of those posts;

http://www.audioasylum.com/forums/HUG/messages/49834.html

http://db.audioasylum.com/cgi/m.mpl?forum=hug&n=50017&am p;highlight=labsub&r=&session=

Then, at some point "the light went on" in your head and you accepted that the heavy strong driver approach you had vigorously argued against, might work after all.

But…. You saw flaws that you could solve if you only ignored one of the main design criteria (the size the group requested) an went "push pull" which reduces  the least offensive 2nd harmonic distortion component.  This, without bothering to mention when the Lab sub was already the lowest distortion sub measured at the  real Sub shoot outs.
Then you began painting a picture about the driver being "easy" to damage but thankfully your "rear hole"  plug fixes that too you claim (at least with your test signal).
This too without bothering to mention that the Lab sub was the most powerful of the subs tested in the Sub shoot-outs.

This is very unfair to Eminence and the PSW Labsub forum, you have never even built a single lab sub let alone played /measured an array of them as they are to be used.  While your "predictions" don’t show it, even the measured response for one lab is within 1 dB or less of your measured response.
You have no idea (at least using the response model you show) what an impedance curve for 4 or 6 looks like compared to the Pi copy, THAT impedance is what will govern the I^2 X R heating in the VC.  Your revised box reaches Xmax first, will be less efficient, produce more heat in a large group.

You have not couched your criticism of the driver in terms of how loud / low a Lab sub setup goes compared to some of the very expensive, very inaccurately specified "Pro Sound" subs that the majority buys.  That is partly why I offered to design the darn thing in the first place, to help foil some of the silly / impossible claims that were made about some popular subs.
Also, unlike you, this was not "for profit" venture, I have no PI forum, there is no organization that benefits from this, except possibly for Eminence who offered to make the driver "back then" and PSW who hosts the site..

Lastly, step back and consider your challenge, who / what are you challenging?
Why would a sound company, who has a group of Labs and knows what they do, haul them to your site so you can see "IF" you can blow them up with "your" test signal and then, assuming they do blow first (with your signal) you ask THEY then pay you $1000 for the privilege?
Your logical process seems chronically flawed somehow.
Cheers,

Tom

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Brian J. Troup Jr.

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Re: Prosound Shootout
« Reply #21 on: August 16, 2006, 11:42:55 AM »

Immaculate response Mr. Danely, as always.  




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Wayne Parham

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Re: Prosound Shootout
« Reply #22 on: August 16, 2006, 01:07:35 PM »


I looked through the posts you referenced, and the links contained inside them.  What exactly are you arguing?

http://www.audioasylum.com/forums/HUG/messages/49834.html
http://www.audioasylum.com/forums/HUG/messages/50013.html

I see posts written by several people.  The posts from me describe how some horns are different than others, and how a horn used from 50Hz to 500Hz would use a different driver than one used for a subwoofer.  I pointed out that the driver chosen should fit the application.  I discuss the conditions of the Webster equation.  I made references to Leach's paper, "A two-port analogous circuit and SPICE model for Salmon's family of acoustic horns".  Each of those posts make reasonable statements, so what exactly are you arguing?  Can you point to some statement in one of them that you disagree with?

As for the push-pull drive, what are you trying to say?  I think reduction of the second harmonic from cancellation is desireable, don't you?  The third harmonic is reduced by the horn folds and the fourth is reduced by both push-pull cancellation and horn folds.  Using two woofers makes push-pull drive possible.  I think it's a good idea.  Why don't you?

About the cooling plug wager, are you interested?  Do you think that placing aluminum plates on the LABhorn in near proximity to the drivers helps cool the motors?  Do you think that the cooling plug is ineffective?  If so, are you willing to put your money where your mouth is?

Because I think the aluminum plate on the LABhorn is competely ineffective for providing "an improved heat path to the outside world" as your drawings indicate.  There is no heat conduction path, so the access panels don't cool the drivers one whit.  Install cooling plugs, and the access panels become very effective heat sinks.  That's what I think, and that's what tests show.  I'm extremely confident in these facts, enough to bet on it.  Are you?
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Wayne Parham
π Speakers
PiSpeakers.com

Brian J. Troup Jr.

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Re: Prosound Shootout
« Reply #23 on: August 16, 2006, 01:37:54 PM »

Things are heating up now!

(Get It?) Laughing
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John Roberts {JR}

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Re: Prosound Shootout
« Reply #24 on: August 16, 2006, 02:09:04 PM »

Wayne Parham wrote on Wed, 16 August 2006 12:07


I looked through the posts you referenced, and the links contained inside them.  What exactly are you arguing?

http://www.audioasylum.com/forums/HUG/messages/49834.html
http://www.audioasylum.com/forums/HUG/messages/50013.html

I see posts written by several people.  The posts from me describe how some horns are different than others, and how a horn used from 50Hz to 500Hz would use a different driver than one used for a subwoofer.  I pointed out that the driver chosen should fit the application.  I discuss the conditions of the Webster equation.  I made references to Leach's paper, "A two-port analogous circuit and SPICE model for Salmon's family of acoustic horns".  Each of those posts make reasonable statements, so what exactly are you arguing?  Can you point to some statement in one of them that you disagree with?

As for the push-pull drive, what are you trying to say?  I think reduction of the second harmonic from cancellation is desireable, don't you?  The third harmonic is reduced by the horn folds and the fourth is reduced by both push-pull cancellation and horn folds.  Using two woofers makes push-pull drive possible.  I think it's a good idea.  Why don't you?

About the cooling plug wager, are you interested?  Do you think that placing aluminum plates on the LABhorn in near proximity to the drivers helps cool the motors?  Do you think that the cooling plug is ineffective?  If so, are you willing to put your money where your mouth is?

Because I think the aluminum plate on the LABhorn is competely ineffective for providing "an improved heat path to the outside world" as your drawings indicate.  There is no heat conduction path, so the access panels don't cool the drivers one whit.  Install cooling plugs, and the access panels become very effective heat sinks.  That's what I think, and that's what tests show.  I'm extremely confident in these facts, enough to bet on it.  Are you?



Nobody says reducing second harmonic or adding extra heat sinking is bad, only that it may not be worth the effort. You have made your position clear (ad nauseum). Tom was also clear in his response.

Speaker design is tradeoffs lumped on top of tradeoffs. There can't be a purely objective answer to the debate if there isn't first agreement to what parameters to optimize. . You need to agree to disagree and move on. Repetition may work in advertising, in discussions of fact it serves no purpose.

JR
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Wayne Parham

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Re: Prosound Shootout
« Reply #25 on: August 16, 2006, 02:17:45 PM »


So what's worth extra effort to you?
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Wayne Parham
π Speakers
PiSpeakers.com

John Roberts {JR}

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Re: Prosound Shootout
« Reply #26 on: August 16, 2006, 02:19:53 PM »

not this...

JR
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Antone Atmarama Bajor

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Re: Prosound Shootout
« Reply #27 on: August 16, 2006, 02:24:08 PM »

     Hey Thats because your an amp, and drum fiend!!!   Razz
Not a speaker geek!!!

Antone-
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Wayne Parham

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Re: Prosound Shootout
« Reply #28 on: August 16, 2006, 02:26:01 PM »


Why even use aluminum for the access panel in the first place?  It doesn't do anything unless cooling plugs are installed, so why make it out of aluminum?  That's an extra effort and it doesn't even do anything.  Add the cooling plugs and it actually works as a heat sink.
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Wayne Parham
π Speakers
PiSpeakers.com

Wayne Parham

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Re: Prosound Shootout
« Reply #29 on: August 16, 2006, 02:29:20 PM »

http://www.audioroundtable.com/images/Laughing_Felix.gif
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Wayne Parham
π Speakers
PiSpeakers.com

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