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Old 4th September 2011, 01:41 AM   #101
eyoung is offline eyoung  United States
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Location: Sunny SC,USA 15 min south of Charlotte NC
Is it a function of slot volume versus the +/- volume of air moved by the drivers and is there a good ratio of driver volume versus slot volume as if the drivers move 6 liters of air and the slot is half the driver volume then not counting mechanical losses then the air in the slot moves at 2x the V of driver V...given velocity of air is a function of driver cone velocity and volume changes with amplitude of the signal to the driver there has to be a " sweet spot " for a driver to slot ratio.

I think I need another glass of wine

I think that was a question with out a question mark treat it as such ....

Regards, Elwood

PS there are those that do not frequent these forums and I know some personally it is mainly behind the scene sniping that makes them seek other forums to vent or share. we have lost some great thinkers on these list, try to not take things personally. we all have a right to our opinions we also have a right to believe or discent(sp). discussions like these is where great ideas are born or reborn.

OK I'm going for that glass of vino
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Old 4th September 2011, 07:25 AM   #102
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Location: Texas
Hi eyoung,
I lived 50 years near and around Greenville,SC been to your neck of the woods many times,have relatives in concord,Charlotte.
Thanks for all the nice comments and I got your drift,I'm surprised some of the smarter people even reply to some that post here,I think some folks gotta fuss,maybe it gets them off, I like a more layed back approach,fine women,good wine and great music,what else you need?I like parties people come over and bring food,wine and music to put on my system ,what a pleasure to entertain all the senses!and have request to play my creation for them !
I got all I need to start one unit build and see how they do,waiting on ups to get them here maybe Tuesday,
Cheers
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Old 4th September 2011, 04:33 PM   #103
winslow is offline winslow  United States
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<- is in Kings Mountain, NC.
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Old 4th September 2011, 04:44 PM   #104
The one and only
 
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If you would like to hear mine, I plan to take them to the Burning Amp
Festival, Oct 1 in San Francisco.

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Old 4th September 2011, 05:19 PM   #105
sreten is offline sreten  United Kingdom
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Location: Brighton UK
Quote:
Originally Posted by CLS View Post
Hi sreten,

No, this is not about technical stuff.

I remember some time ago, we had some 'discussins' in the T-bass circuit
thread. At that time, I was one of the believers, you were the major doubter.
Oh, let me rephrase, no, you didn't doubt, you were certain, very.
Hi,

Regarding that discussion I posted some information about what was going on.

However the OP got shirty about what I was saying (which was verifiable in a
circuit simulator), carried on insisting it did things it doesn't, and then to boot
insisted it was some form of personal attack, which it simply wasn't.

So I left the discussion, because it wasn't one. It was a very interesting
concept, with inevitable consequences the OP did not want to entertain.

Yes, I was certain about what I was saying, and also certain it didn't
do the things it seemed the OP was simply making up, c'est la vie.

It is technical stuff, and it is a matter of mindset. I never said the T-bass
circuit didn't work, it does, and I showed how it essentially worked, along
with the inevitable (lower) impedance transformation it needed to work.

Just because it works doesn't mean the OP's conjectures are correct.
The idea that just because you come up with idea that you are also
the expert on how it works makes no sense. It doesn't work like that.

I like ideas (especially good ones), and understanding what is going on.

rgds, sreten.

Take this 4" full range driver :

Click the image to open in full size.

Stick some form of treble deflector in front of it* to level extreme treble
and improve dispersion. a good idea. I couldn't care less about someone
saying it works, but then saying it does for ridiculous reasons. It should
work anyway, and the best understanding will lead to the best deflector.
I am not of the school poor understanding can lead to the best solutions.

*An idea condemned as very poor in another thread for no sensible reason.
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Last edited by sreten; 4th September 2011 at 05:40 PM.
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Old 4th September 2011, 05:27 PM   #106
tinitus is offline tinitus  Europe
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sounds like debating what came first, the hen or the egg

many posts seem to be 90% off topic, and only 10% on topic

tends to get boring when it continues
and any relevant and good comments it may hold are burried in...
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Old 4th September 2011, 06:33 PM   #107
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Quote:
Originally Posted by Nelson Pass View Post
If you would like to hear mine, I plan to take them to the Burning Amp
Festival, Oct 1 in San Francisco.

Hi Nelson,
I plan to make it this year and that would be a blast for sure!I want to hear all you bring,Could be a fun time too!See you then!
Cheers!
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Old 4th September 2011, 07:52 PM   #108
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I understand they are serving beer this year.



Sreten,

I have no objection to a discussion of why a slot loaded baffle is / or is not
more efficient, and I don't have much investment in whether it is or not -
the loudspeaker works great regardless.

Physical logic tells me that it is, and I get measurably higher spl in my chair,
so I tend to go with that.

As far as appeals to authority, I go back to the lessons Oskar Heil personally
taught me. Incredible as it may seem, Oskar was not always right. So I'm
willing to be convinced otherwise, but as yet, I don't think you've made a
real effort to do so.

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Old 4th September 2011, 08:43 PM   #109
bocama is offline bocama  Netherlands
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Quote:
Originally Posted by Nelson Pass View Post
Perhaps you are simply looking at it the wrong way.

Let's analyze it from another angle using a little physics:

You will agree that the volume of air displaced to the front and back
will have to be the same for practical purposes, the acoustic equivalent
of Kirchoff's law.

Acoustic energy is the product of volume displaced at a given pressure,
the acoustic equivalent of watts = volts X amps.

For a given signal, the pressure out the front is measurably higher at any
reasonable position or distance and it is in phase with the displacement of
the woofers. Therefore, there is more energy going out the front than the
rear.

If it is not sound, where did the energy go?

No that is wrong. It the of preservation of energy law that makes your reasoning improbable. If the pressure is higher it is only possible because the volume displacement is smaller if the volume displacement was the same there will not be a higher pressure. The speaker puts the same pressure on the front air as it puts on the back because the area and force are the same.

Last edited by bocama; 4th September 2011 at 09:03 PM. Reason: making it clearer
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Old 4th September 2011, 09:02 PM   #110
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by Nelson Pass View Post

I understand they are serving beer this year.



Sreten,

I have no objection to a discussion of why a slot loaded baffle is / or is not
more efficient, and I don't have much investment in whether it is or not -
the loudspeaker works great regardless. (A)

Physical logic tells me that it is, and I get measurably higher spl in my chair,
so I tend to go with that. (B)

As far as appeals to authority, I go back to the lessons Oskar Heil personally
taught me. Incredible as it may seem, Oskar was not always right. So I'm
willing to be convinced otherwise, but as yet, I don't think you've made a
real effort to do so. (C)

Hi,

I'm not arguing about (A), I'm not saying it doesn't work, I''m sure its fine.

(B) is the most interesting point, and inadequately described. As I've said
before your "physics" logic implies the narrower the slot the greater the
efficiency increase, I'm saying in reality this simply does not happen.

For (C) :

I don't see Heil's AMT principles being relevant. As first base
Air Motion Transformer - Wikipedia, the free encyclopedia indicates
its all about moving more air, with its relevant pressure increase.
The air speed increase related to diaphragm velocity is inevitable.
It does not imply increased efficiency for a volume displacement.

The point of the Heil is to use magnetic fields more efficiently, it
has essentially the same efficiency as a stretched out diaphragm
with a relatively huge magnetic structure, i.e. its a cheaper way
of moving more air, and being smaller less dispersion issues.

Simply replace every pleat in the AMT with a driver, use a zigzag
baffle and work out what happens at low frequencies, nothing
special. The Heil is special because it uses the fore and aft field
far more efficiently than a planar diaphragm, and that leakage
field will always exist wasted in any planar design, best used.

Packing a say a 30" pleated length into a say 4" length field
has obvious efficiency advantages over a simple 4" planar.
Around 9dB from basic principles, and necessarily the 4" unit
will have higher air velocity and pressure over the 30" planar.

rgds, sreten.

As ever I'm also fallible and sometimes wrong, but not often.
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When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 4th September 2011 at 09:21 PM.
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