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Author Topic: Is the 12pi Subwoofer an upgrade to the LAB?  (Read 24239 times)

Wayne Parham

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #20 on: July 13, 2006, 01:58:09 pm »


The push-pull configuration has been shown to reduce distortion, incorporated by very well respected people like Dr. Linkwitz, EAW, etc.  Any mechanical engineer will confirm that the heat exchanger provides much better cooling than air venting alone.  This, combined with the fact that I went to great efforts to make the cooling plug design compatible with the LABhorn makes your discounting of these things particularly irresponsible, in my opinion.  It has been shown to be very effective, and I think your going to such great lengths to discount it is purely ego driven.  The fact is that lots of people have suffered from LAB12 failures that immediately stopped once they installed cooling plugs.

On a personal level, I'm about sick of this crap from you, Tom.  You're a smart guy, and have done a lot of good work.  So why you've acted this way is beyond me.  You often describe yourself and the companies you work with as "Davids" set upon by industry "Goliaths".  But where you and I have been involved, you're  the one that has been the predatory "Goliath" and I think you should look at that.

Look at the history -  A few years back, I ran a little DIY business that sprung out of my passion for audio, and you were the main guy at ServoDrive.  We really operated on two different levels.  You sold commercial products. I provided free loudspeaker plans and discussed them with hobbyists.

I had several good speakers with plans available at that time, and I still do.  My speakers were popular, sounded good and people were satisfied.  I still have those same speakers available, and people still love them.

You and Seaton started promoting the Unity over on my forum, and barraged us with several posts about it.  I haven't followed your progress with the Unity since then, but frankly, that version sucked.  It had a huge 15dB spiked dip, obviously a crossover anomaly about an octave above the crossover frequency.  Summing was bad, and I said so.  You attacked other loudspeakers, but your own loudspeaker sucked.  The design probably had potential, and you were proud and all, that's fine.  But the implementation sucked and you shouldn't have attacked people when your own product was that poor.

You similarly championed the LABhorn, sort of forcing it down people's throats.  Most of the guys you were talking to ran tiny power tube amps.  They didn't need or want something like the LABhorn.  But you railroaded that thing and some people took offense.  Frankly, the most vocal opponents to the LABhorn were Edgarhorn supporters, not Pi Speakers enthusiasts.

Seems you've never let go of those controversies.  I've tried to move on and treat you like a gentleman, but you seem bent on keeping a fight going.  It is so bad that you criticize things you know better, things that you know work well.  The push-pull configuration reduces distortion and you know it.  But instead of saying that, you criticize it because you are still hanging on to sour grapes.  That does a disservice to all those that look up to you.

And the worse thing is how you've discounted the cooling plug.  On that matter, I'm not sure if you know it works and just discount it out of spite, or if you really don't understand heat transfer.  You're a smart guy, but you're not a mechanical engineer.  It is possible that you don't know how much effect black body radiation has on the heat transfer inside the motor.  It's not really your field of expertise, and even if you get a patent on something, that doesn't make you expert in the field.  It just means you've done something (for right or wrong) that no one else paid the PTO to register as being novel.  But whether or not you understand the significance of this, you could have tested it and your discounting it without testing is extremely irresponsible.

Next time you post something about the cooling plug, consider running it by a degreed mechanical engineer.  People look up to you here, and you've promoted yourself as a "Myth Buster".  So I'd appreciate it if you'd stop spreading so many myths of your own.
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Wayne Parham
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Gareth James

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #21 on: July 13, 2006, 02:00:51 pm »

Wayne the 12pi pushes the lab12 driver harder than the original labsub design. IMO too hard.

The "dip in response" which you are always referring to as having been part of your reasoning for "designing" (note the loose use of this term) the 12pi appears quite less pronounced in actual measurement. The effect it has on adequately damping the driver at very low frequencies still remains however whereas your 12pi horn only increases distortion for little gain.

I had no idea that there had been a DIY unity horn in concept, to learn that you had involvement in its undoing irritates me somewhat.

I blow my nose at you!



EDIT: Wayne as Tom already explained in a calm and reasonable fashion, the push pull configuration only reduces EVEN harmonic distortion and as I already mentioned in another post the original Labsub design wasn't exactly high in distortion. In fact maybe your push-pull design almost makes up for the extra excursion the drivers are dealing with in the 12pi.

As far as the cooling plug, as (once again) Tom has already explained quite adequately musical signals do not bear much if any resemblance to steady state signals. Drawing comparisons from measurements using steady state signals cannot be accurate. The cooling pipe may wick heat away over long periods but during a short burst of energy the only cooling going on will be the voice coil directly giving off heat to its immediate surroundings.
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Wayne Parham

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #22 on: July 13, 2006, 02:11:27 pm »


As I am irritated with anyone that discounts serious design efforts prior to honest examintation.  I suggest you consult a degreed mechanical, electrical or acoustical engineer before making attacks on things that you have not properly investigated.  As an example, go find a degreed mechanical engineer and ask them about the heat exchanger idea, see what he says.  Then go get a napkin for your nose.
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Wayne Parham
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Gareth James

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #23 on: July 13, 2006, 02:19:55 pm »

Wayne I can't be bothered answering you on 2 posts so I shall concentrate my efforts on this one. As I thought I'd already explained clearly, my points were taking into account your meticulous tests and the fact that steady state power is not an accurate representation of power handling.

I wasn't entirely discrediting your idea. I just don't believe the extra long-term wicking power of the heatsink will aid the staying power of the voice coil with large musical peaks as much as it would with a constant signal.

I'd also be pretty suprised that if the fellow who managed to burn 16 labs multiple times didn't also learn to turn it down a notch eventually. As real as real world performances get its still impossible to subjectively analyse the results of one evening to the next, there will ALWAYS be differences.
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Wayne Parham

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #24 on: July 13, 2006, 02:24:08 pm »


You haven't tested the cooling plug.  I have.  The fact is that it significantly increases power handling and reduces thermal compression.  Bass is bass, and power is power.  The motors get hot, and whatever you can do to cool them down helps a great deal.  Again, go ask a mechanical engineer about this concept.  Or build some cooling plugs and try them out.  Or both.
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Wayne Parham
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Gareth James

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #25 on: July 13, 2006, 02:54:33 pm »

Wayne as I thought I'd made clear what feels like a few dozen times now, I'm not debating the fact that a large heatsink will aid long term cooling. Yes you have indeed performed AFAIK one destructive test involving 2 woofers (hardly definitive evidence) but using cycled sine waves.

As you said yourself the woofer fitted with the heatsink was still suffering from power compression artifacts above 500w or so. How can you say then that the motor has had its (useful) power handling more than doubled?

I would like to see more conclusive/exhaustive/whatever testing of your device, although I admit I'm not sure how that could be accomplished. I am simply making the point that the electrical power handling of the original LAB driver IMO was largely governed by the 2.5" voice coil.

I just can't see how a heat wicking solution post coil is going to stop a sudden burst of energy from generating enough heat at the coil itself to potentially cause damage. Maybe a different set of tests would prove/disprove this.
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Wayne Parham

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #26 on: July 13, 2006, 03:46:16 pm »


The information is there, take it or leave it.

I'll also suggest that engines with water-cooled heads develop more power than those with air-cooled heads.  You can argue all day long that combustion is a fairly transient thing and that the intake charge passes through much too rapidly for head temperature to matter.  But you'll be arguing it alone, while the engine with better cooling is lapping you on the track.

Don't be fooled.  This isn't some kind of weird widget.  It works, works well, and its benefits are rather obvious, to be very blunt.
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John Roberts {JR}

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #27 on: July 13, 2006, 04:50:44 pm »

Wayne Parham wrote on Thu, 13 July 2006 14:46


The information is there, take it or leave it.

I'll also suggest that engines with water-cooled heads develop more power than those with air-cooled heads.  You can argue all day long that combustion is a fairly transient thing and that the intake charge passes through much too rapidly for head temperature to matter.  But you'll be arguing it alone, while the engine with better cooling is lapping you on the track.

Don't be fooled.  This isn't some kind of weird widget.  It works, works well, and its benefits are rather obvious, to be very blunt.




Be sure to let us know when you finish water cooling your voice coils as that would surely be superior. Might as well water cool your power amps too. Laughing

I don't think anybody is disputing that adding your heatsink could help under the right conditions. I for one would like to hear from some actual live SR users. That is IMO the definitive test, real world use. We already know pretty well how you feel about it.

JR
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Wayne Parham

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #28 on: July 13, 2006, 06:28:21 pm »


I've already told you that there are plenty of these cooling plugs in the field, and everyone gets the same results I have.  The motor stays cooler, it's pretty simple.

My comments about this device aren't motivated by how I "feel".  They come from what I know, based on what I've tested and from results in the field.

Some of the posts I see here on the heat exchanger subject are sort of like reading "the Earth is flat because the Pope said so" or "you're stupid not to listen to the Pope".  What happened to the ideals of this forum, where actual measurements trumped speculation?  Looks to me like that has gone out the window.

I won't put anyone on the spot, but I will tell you that there are a lot of people that have stopped posting because of the attitudes here.  There are some good people that haven't been around in a while, and it is because they see people they used to respect saying things they know not to be true.  What we see now are insults hurled at anyone that does something to improve the LABhorn.  Why would anyone subject themselves to this?
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Wayne Parham
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John Roberts {JR}

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Re: Is the 12pi Subwoofer an upgrade to the LAB?
« Reply #29 on: July 13, 2006, 07:44:56 pm »

Wayne Parham wrote on Thu, 13 July 2006 17:28


I've already told you that there are plenty of these cooling plugs in the field, and everyone gets the same results I have.  The motor stays cooler, it's pretty simple.

My comments about this device aren't motivated by how I "feel".  They come from what I know, based on what I've tested and from results in the field.

Some of the posts I see here on the heat exchanger subject are sort of like reading "the Earth is flat because the Pope said so" or "you're stupid not to listen to the Pope".  What happened to the ideals of this forum, where actual measurements trumped speculation?  Looks to me like that has gone out the window.

I won't put anyone on the spot, but I will tell you that there are a lot of people that have stopped posting because of the attitudes here.  There are some good people that haven't been around in a while, and it is because they see people they used to respect saying things they know not to be true.  What we see now are insults hurled at anyone that does something to improve the LABhorn.  Why would anyone subject themselves to this?



I can't and won't speak for what other people think.

I won't respond to; The Pope, "Flat Earthers", forum ideals, missing regulars or any of the other misdirection.

This is a public forum with no verifiable credentials or technical certification required before posting. I don't know you and you don't know me so all we can each do is make judgements based on how information is presented and how we comport ourselves. In matters of fact all we need do is wait for the "rest of the story". The beauty of this place is that it is still frequented by enough knowledgeable people that the BS is kept down to a steady roar and doesn't take over.

You have already presented your case, a little forcefully for my taste, but no matter. I'm waiting for some real users with applicable first hand experience to check in. I don't need you to tell me the same thing again. Frequency may improve results in advertising but in matters of credibility it can hurt and some independent corroboration, preferably from LAB regulars would be far more effective.  

I'm sorry if my sarcasm seems a little pointed. I'm not attacking you, just the inappropriate analogies, and lack of modesty in making performance claims.

It's OK to be proud of your designs, and defend them if you feel they've been maligned, but this is not a court of law and there is no easy mechanism to verify performance claims. Credible evidence in this court of opinion comes from other peoples experiences. Don't waste your time trying to convince me.  

JR  
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