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Author Topic: Push pull configuration for LAB Horn?  (Read 17961 times)

Pascal Pincosy

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Re: Push pull configuration for LAB Horn?
« Reply #30 on: August 17, 2007, 01:02:50 am »

Hey Vince, This has all been rehashed and re-rehashed to death. Over and over and over again. Wayne's had his Pi Horn at both the measurement shootouts he's done and distortion measurements were taken and are available online.

Now I'm not privy to all those early discussions (thank god Rolling Eyes ) and I certainly can't speak for who said what. But this thread after thread after thread about the same stupid stuff is pretty stale and I'm certainly tired of reading it. People need to either kiss and make up, or take it off-line, or at least find something new and more interesting to argue about.

Fact: The Pi horn has less distortion because it uses the push-pull. This makes it wider. Thus it doesn't truck-pack as well as the LAB horn. Compromise.

Fact: Wayne's cooling plug reduces heat buildup in the driver. This is a good thing. Cabinets built in this manner are somewhat less user-friendly as flaps or spacers are needed to allow for proper cooling. Compromise.

What it all comes down to is that Tom Danley built a subwoofer for the LAB, to their specs. Wayne Parham built one for himself, to his specs. They are different speakers made for different purposes. There is no better here.

And who the hell cares if Wayne is trying to "compete" with a free design anyway? Tom's not losing any sleep over it. His company is growing by leaps and bounds, and they don't make a dime from the LAB horn. Like I said, I wasn't around back in the day when this schism started, so to me, it all reads like a pissing contest where the goal is to soak your own shoes.

I'd like to remind everyone of an old chestnut: "Imitation is the sincerest form of flattery." Can we get back to talking about how JBL is the best or how to build a better sub for our Honda's already?
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Vince Byrne

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Re: Push pull configuration for LAB Horn?
« Reply #31 on: August 17, 2007, 08:23:01 am »

Pascal Pincosy wrote on Fri, 17 August 2007 00:02

Hey Vince, This has all been rehashed and re-rehashed to death. Over and over and over again.

Yeah, I'm done. Wayne asked "why are they picking on me" and I took the bait. As if he doesn't know. I'm so ashamed ...
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Todd Michael

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Re: Push pull configuration for LAB Horn?
« Reply #32 on: August 17, 2007, 08:42:26 am »

Wayne,

I think, as usual, you are seeing things from your own perspective and nobody else's. First off I never publicly bashed any of your products and I did mention that I thought the 12pi was probably a fine sounding sub. What I "bashed" was you and your attitude towards the LAB sub from day one. It is well documented that you were not a fan of the design or the designer right from the word go. And here you are now with a very similar design and you have never given any credit (that I have seen) to Tom for the work he has done.


I think you should go back and read the AA posts again about what you would build specifically for the LAB, NOT HOME HI-FI, we were not talking about home Hi-Fi applications and I made that very clear. Your answer was a bunch of direct radiator cabinets loaded with JBL drivers.You said that one of the biggest design targets was that it had to be portable and you thought bass horns like the LAB sub were too big to be portable, then you make the 12pi which is even bigger!

The obvious question why did you not make a new product like that instead of making the 12pi?

Next to Tom I'm pretty sure I have done more work with the Unity design than anyone else so I am very aware of its similarities to previous designs. But the difference between Tom and R.H and you and the 12pi and LAB sub is that Tom was never publicly bashing the R.H co-entrant design and then months later came out with the Unity. I think Tom even sited the RH design as previous art in his patent.


 Like I said in my first post you can argue about your push/pull drivers and heat plugs all you want. I am very aware of their benefits and I did not discredit them or the work you have done designing them, again I think you are missing the point.

I can see this just going around and around in circles. I guess you will have your view point and I will have mine of the events that unfolded since the beginning of this project and that is fine.

Todd
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John Roberts {JR}

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Re: Push pull configuration for LAB Horn?
« Reply #33 on: August 17, 2007, 10:15:22 am »

I continue to be amazed at how much energy people spend trying to change the opinion and behavior of others. I haven't yet mastered changing my own.

It is not surprising that people will have a personal perspective, perhaps colored by self interest. This is just being human.

The past is past and can't be changed with any amount of hand wringing.

Perhaps we can get back to talking about something new or different, and not rehashing the same old nonsense.

JR
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Wayne Parham

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Re: Push pull configuration for LAB Horn?
« Reply #34 on: August 17, 2007, 12:02:22 pm »


Todd Michael wrote on Fri, 17 August 2007 07:42

What I "bashed" was you and your attitude towards the LAB sub from day one. It is well documented that you were not a fan of the design or the designer right from the word go.


I wasn't "a fan of the design or the designer right from the word go", that's true.  Well, maybe I should correct that just a little bit.  I didn't have a problem with Danley and his associates at first.  I probably would have liked him just fine and agreed with many of his design principles if we had met on different terms.  But you see, my introduction to Tom Danley was by way of his associate Mark Seaton coming into the Pi Speakers support forum and bashing our speakers, championing his own Unities instead.  So you're right that, at least after that time, I wasn't a fan of the "designer right from the word go".

Todd Michael wrote on Fri, 17 August 2007 07:42

And here you are now with a very similar design and you have never given any credit (that I have seen) to Tom for the work he has done.


Perhaps you didn't read this:


Todd Michael wrote on Fri, 17 August 2007 07:42

I think you should go back and read the AA posts again about what you would build specifically for the LAB, NOT HOME HI-FI, we were not talking about home Hi-Fi applications and I made that very clear.


Maybe you should re-read the posts.  There's a link to them in this thread, so it's easy to do.  It was started by a guy that was building a home hifi sub.  The whole Asylum website is dedicated to home hifi hobbyists.  My position was very clear there, and I have not changed it to this day.

Todd Michael wrote on Fri, 17 August 2007 07:42

Your answer was a bunch of direct radiator cabinets loaded with JBL drivers.


That would be an excellent choice for small venues, like home hifi.  Especially if the goal is use below 30Hz, a direct radiating subwoofer makes more sense than a 30Hz basshorn with the bottom end EQ'ed up.  Just like I wouldn't suggest the LABhorn in that situation, I wouldn't recommend my 12Pi to someone for home hifi, or for use below 30Hz.

Todd Michael wrote on Fri, 17 August 2007 07:42

You said that one of the biggest design targets was that it had to be portable and you thought bass horns like the LAB sub were too big to be portable, then you make the 12pi which is even bigger!


No, I said a basshorn has to be large to work at low frequencies.  One that is small enough to be portable is severely compromised at low frequencies.  Again, for home hifi, it's probably overkill to use a LABhorn or a 12Pi and they aren't designed to be used below 30Hz anyway.  My suggestion was to use a direct radiating sub that was tuned lower.  It would be smaller and have lower f3.

Todd Michael wrote on Fri, 17 August 2007 07:42

Next to Tom I'm pretty sure I have done more work with the Unity design than anyone else so I am very aware of its similarities to previous designs.


The Renkus-Heinz CoEntrant design and the Danley/Yorkville Unity/Summary are exactly the same thing.  I'm sure the patent was granted based on a small detail that Danley claimed was different, but the principle is exactly the same.  If it weren't, one of them wouldn't work.  They are physically similar so they must be configured similarly too.

Especially in light of that, I think it is extremely wrong for you or any other Danley supporter to point to the 12Pi and say it's a copy of the LABhorn.  I spent hundreds of hours working out the details.  It was a significant effort.  There is a considerable amount of design, testing and refinement that was required to perfect the design.

The layout of the motor chambers was completely different in order to support push-pull drive.  The cooling plugs were the result of considerable effort, starting first with a ducted air-cooling system and evolving later into the cooling plug which was much more effective.  Then there was the matter of layout, and how to position everything in the cabinet.  The end result allowed me to make a cooling plug that was simple, and is compatible, allowing it to be used on the LABhorn.  That was a contribution I made to the people here.  But do you give me credit for it?  No, you shrug it off and minimize it.  That's wrong, very wrong.

If you and Tom and other Danley associates want to come here and minimize my efforts, don't be surprised when I do the same to yours.

Todd Michael wrote on Fri, 17 August 2007 07:42

Like I said in my first post you can argue about your push/pull drivers and heat plugs all you want. I am very aware of their benefits and I did not discredit them or the work you have done designing them, again I think you are missing the point.


That's complete BS.  Tom Danley and Ivan Beaver both took a position that they didn't work.  You may not personally have made those comments, but Tom and Ivan did.  They are seen as experts in the field, so when they make statements, sometimes people believe them without checking the facts.  That's not cool.

Tom and Ivan were pretty vocal about trying to discredit the cooling plug approach last year. It was incredible to me, since any competent mechanical engineer that examines the device immediately understands what it does and how it works.

Tom's position was that radiated heat was not significant.  That's not true at all.  Not only was he wrong, but he was rude about how he tried to discredit me and the cooling plug approach.  What he would have found, if he actually did some tests, is that the whole motor core is heated by energy radiated by the voice coil.  One of the most effective things you can do to reduce voice coil temperature is to wick away the radiated heat.  Keep the forced air cooling from the gap vents, and add to it some cooling plugs.

When several hundred watts are applied to a speaker voice coil, it gets hot like a large soldering iron. Even if the speaker system is very efficient, you still have hundreds of watts dissipated as heat. Take a theoretical 400 watt speaker at a very optimistic 50% efficiency level - You still have 200 watts of heat. This heat source is surrounded by steel and then covered by a large chunk of ceramic. This is a pretty good heat container, one that is almost made to hold heat. So one of the best things you can do is to get a good conductor of heat down inside the motor, in contact with the pole piece. Wick the heat out of the core and radiate it away.

It's the most effective thing I've ever seen for removing built-up heat from the motor core.

John Roberts  {JR} wrote on Fri, 17 August 2007 09:15

I continue to be amazed at how much energy people spend trying to change the opinion and behavior of others. I haven't yet mastered changing my own.

It is not surprising that people will have a personal perspective, perhaps colored by self interest. This is just being human.

The past is past and can't be changed with any amount of hand wringing.

Perhaps we can get back to talking about something new or different, and not rehashing the same old nonsense.


I agree, wholeheartedly.  I'm sorry for my part in the deal.  

I've tried to let this die for the past year or two, but Danley and company keep attacking me.  It has been the same since I first encountered them, and I never understood it.  From the first time they rudely came into my forum and started pushing the Unities, I was pretty miffed.  I pushed back, sometimes pretty hard, and maybe that was my mistake.

But I'm not the only one Danley has attacked.  I see him putting down others too.  Sometimes it is an overt attack, like what he does to JBL or EAW.  Other times, it is more like a patronizing comment, one that kind of says "you're OK if you stay in your place" but with the inference that he is king of the hill.  I see this in comments about Bassmaxx and others that participate here.  None of these guys like it, and in most cases, it isn't fair or even truly accurate.  It's spin, and I don't like it.

I make loudspeakers because I love to do it.  I'm proud of my work.  They very good products and people like them.  They are technically advanced and definitely worthwhile, at least in my opinion.  They're my best work.

All of my designs are offered to the DIY community.  I don't have some that are proprietary and others that are open.  All my designs are open.  I don't charge for the plans, even for products that have been developed at great expense of time and money.  This started as a hobby of mine, and just kind of took off.

So I have taken extreme offense to Danley trying to bully me over the years.  How am I to respect a man that acts like that?  Still, I've let things slide for the most part.  Look back through the threads Danley and I have been on in the past couple years and I think you'll see I've been restrained even when being patronized or outright attacked.  So I've let it drop, let it roll off.

I'm happy letting the truth express itself.  It always does in the end.
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John Roberts {JR}

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Re: Push pull configuration for LAB Horn?
« Reply #35 on: August 17, 2007, 12:37:21 pm »

stop stirring the pot...

JR
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Ivan Beaver

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Re: Push pull configuration for LAB Horn?
« Reply #36 on: August 17, 2007, 01:10:06 pm »

I have been deliberately staying out of this so not to prolong the thread and was waiting for it to die, but I feel I must step in here, since I was accused directly.

It is not mine (nor Tom's) suggestion that the cooling plugs do not work.  I sure they do help.  It is my thoughts that they do not add all the benefit that is claimed.  Yes I assume it is possible to achieve the results you have regarding the power handling increase that you have claimed. That is not to dispute.

What I have a problem with (as stated in earlier threads) is the test procedure used.  You were using a continuous source and music is far from that.  Music has a higher crest factor than you were using, so the tests were not representative of the real world conditions.  SO the idea that now the driver can handle that much extra music power (and the peaks associated with it-those are the real danger) I feel is in error.

If I am not mistaken, you only burned a couple of drivers.  It takes more than that to establish an "average" or baseline-especially for failure conditions.  1 or 2 is not an average.  I seriously doubt that you burnt say at least 10 drivers with and without your plug.

Yes there are some similarities between the Unity and the co-entrant devices.  Yes they both use the same horn for both bands (except the unity-as in the TD1 was a 3 way device while the RH is a two way device).  The co-entrant used a "waveguide" to get the mids into the horn, while the unity mid path is much shorter.  The unity also has different expansion rates for the highs and mids (and lows as well) which allows the horn to load the different bands as needed.

As a result the unity arrays better up higher in freq, because the walls of the cabinet are closer to the HF driver than in the case of the co entrant.

The crossovers were derived ENTIRELY different.  The co-entrant was just a crossover based on a certain freq-as normal.  The unity has overlapping filters and uses the delay associated with the phase shift of those filters to achieve a flatter amplitude and phase response (the biggest issue in Tom's world).

The holes in the unity are acting as low pass filters on the mids as well.

This is in no way dissing the co-entrant (in fact I think it was one of RH's better sounding boxes), but the basic idea of having all the drivers occupy the same physical place in space is one that has been sought after for many years.  Different people are trying different approaches the get there, some better than others.

In regard to the Jensen, it looks a lot more like a transmission line than a tapped horn.  The "horn" part is missing.  Yes Toms earlier experimental work did look more like a transmission line than it does now.  Of course the new stuff works much better-Just wait!

Back in my hole now. My apologies to those who wanted this to die.
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Pascal Pincosy

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Re: Push pull configuration for LAB Horn?
« Reply #37 on: August 17, 2007, 02:04:02 pm »

And round and round the broken record goes. Now Wayne will retort with his views on why the cooling plug's testing was great. This is nothing new. We have heard it all for at least a year now.

It's clear to me that these arguments have little to do with science and a lot to do with bruised egos on both sides. If you guys had all stuck to discussing the facts and the science, and left out the ad hominum in the first place, we wouldn't be here today.
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Wayne Parham

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Re: Push pull configuration for LAB Horn?
« Reply #38 on: August 17, 2007, 03:54:53 pm »


Pascal Pincosy wrote on Fri, 17 August 2007 13:04

And round and round the broken record goes. Now Wayne will retort with his views on why the cooling plug's testing was great. This is nothing new. We have heard it all for at least a year now.


Seems like it, doesn't it?  I won't rehash how the testing was done, but I think maybe we're getting somewhere on an understanding of the significance of radiated heat and how the cooling plug works.  So please bear with me while I reply to Ivan.

Ivan Beaver wrote on Fri, 17 August 2007 12:10

It is not mine (nor Tom's) suggestion that the cooling plugs do not work.  I sure they do help.


They do help, a great deal.

Tom Danley has maintained a position that radiant heat is not significant and that the pole piece is heated by conduction through the air.  Perhaps you guys are now realizing this is not true.  Most of the heat in the pole piece is radiated from the voice coil, not conducted through air in the gap.  That's important, because if you assume center pole heat comes from conduction through air, then it is natural to assume air cooling will remove all the heat.  It looks like that is what Tom assumed, so I can see why he would think the cooling plug wouldn't be effective.

To be honest, that's how I thought for a long time too.  My first attempt at loudspeaker cooling used a ducting arrangement to improve the forced air convection cooling provided by the gap vents.  What I found was even when the air was made very cool and blown through the gap, it did almost nothing to remove heat from the pole piece and magnet.  Radiated heat becomes a big problem at extended high power levels, because it builds up in the motor core and cooks the voice coil, weakening the adhesive.  But as I said, my first assumption was air cooling would remove all the heat.  I don't fault Tom for this assumption because it is an intuitive assumption to make.


After realizing the significance of radiated heat, I wanted to make this information known, so it could be useful to everyone.  To tell the truth, it made cooling improvements pretty easy.  The cooling plug is very easy to make and implement.  That's the important information I bring here.  I don't think it's anything revolutionary, and certainly mechanical engineers look at it and say "duh".  It has been overlooked, I think, by some.  That's why I have said it here.

Some heat is removed from forced air convection through the gap vent.  But a lot of heat is trapped in the motor core that cannot be effectively removed by forced air convection.  That's because it is radiated into the pole piece and magnet in the first place.  To get it out, the best way to do it is to conduct it out with something in direct contact with the pole piece.  That's why the cooling plug works so well.  Best to do both, air cooling through the vents and heat wicking using a cooling plug to some sort of heat sink.

Ivan Beaver wrote on Fri, 17 August 2007 12:10

It is my thoughts that they do not add all the benefit that is claimed.


What is claimed is that cooling plugs reduce temperature in the motor core, and all the benefits this brings.  Specific measurement data has been provided.

Ivan Beaver wrote on Fri, 17 August 2007 12:10

Yes I assume it is possible to achieve the results you have regarding the power handling increase that you have claimed. That is not to dispute.


So which is it, Ivan?

On one hand, you say you're sure they do help, and you assume the power handling increases when using them.

On the other hand, you say they might not add all the benefit that was claimed.

What is claimed is that cooling plugs reduce temperature in the motor core, and all the benefits this brings.  The temperature reduction is significant.  It stabilizes electro-mechanical parameters, reduces compression and makes the speaker more robust and durable.

Ivan Beaver wrote on Fri, 17 August 2007 12:10

What I have a problem with (as stated in earlier threads) is the test procedure used.  You were using a continuous source and music is far from that.  Music has a higher crest factor than you were using, so the tests were not representative of the real world conditions.  SO the idea that now the driver can handle that much extra music power (and the peaks associated with it-those are the real danger) I feel is in error.


Tell you what.  Make one and test it for yourself.  Get some aluminum tubing from McMaster-Carr and lathe it to fit.  Give it a try and see what you learn from it.

Pascal Pincosy wrote on Fri, 17 August 2007 13:04

It's clear to me that these arguments have little to do with science and a lot to do with bruised egos on both sides. If you guys had all stuck to discussing the facts and the science, and left out the ad hominum in the first place, we wouldn't be here today.


That's absolutely right, Pascal.  Let's stick to discussing the facts.  The data speaks for itself.
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Grant Rider

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Re: Push pull configuration for LAB Horn?
« Reply #39 on: August 27, 2007, 12:42:48 pm »

Since even the naysayers have agreed that cooling plugs and push pull woofers are improvements I'm not sure what there is to argue about. I missed a lot of this but what I see looks petty as hell. The protestations here remind me of Topsy the Elephant.
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