| 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.
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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.
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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.
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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.
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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!
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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.
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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.
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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.
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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.
Author
Topic: Push pull configuration for LAB Horn? (Read 23873 times)