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Old 7th May 2009, 12:59 AM   #3341
JLH is offline JLH  United States
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Default Re: impulse response

Quote:
Originally posted by tb46
Hi JLH,

quote: "... but is that a good impulse response? What does one look for in a "good" impulse response?"

For a tapped horn it looks quite good to me, actually looks better than the simulated response for the SPUD, but then there is the question, how do they compare in a measurement, and more importantly what do they sound like?

There is always something else to investigate, there may actually be a reason why I have always ended up with dual 15" in sealed boxes. :-)

Regards,

My best guess is that a nice single peak impulse response that does not have much ringing afterwards would be the better performer. I could see the undampened pulse possibly leading to more second order distortion for single woofer tapped horns. For push-pull tapped horns, I guess a poor pulse would mean there would be smearing due to gross amounts of undampened stored energy. Iím glade David was able to add this feature to Hornresponse.

Rgs, JLH
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Old 7th May 2009, 09:18 AM   #3342
kees52 is offline kees52  Netherlands
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here some information, and a list of drivers suitable for tapped horns.

http://www.t-linespeakers.org/projec...ar/rhinos.html
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Old 7th May 2009, 11:49 AM   #3343
JLH is offline JLH  United States
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Quote:
Originally posted by kees52
here some information, and a list of drivers suitable for tapped horns.

http://www.t-linespeakers.org/projec...ar/rhinos.html

A woofer being suitable for quarter-wave use does NOT mean it is suitable for a tapped horn. A tapped horn is NOT a quarter-wave box. A tapped horn works differently than a quarter-wave box. Please do not confuse the two as being the same thing.

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Old 7th May 2009, 01:26 PM   #3344
MaVo is offline MaVo  Germany
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What does an impulse response tell me which is NOT allready visible in the frequency response?
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Old 7th May 2009, 02:32 PM   #3345
tb46 is offline tb46  United States
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Default Impulse Response

Hi MaVo,

I found this Wikipedia article informative:

http://en.wikipedia.org/wiki/Impulse_response

Regards,
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Old 7th May 2009, 03:43 PM   #3346
GM is offline GM  United States
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Quote:
Originally posted by kees52
here some information, and a list of drivers suitable for tapped horns.
These are (reverse) tapered quarter-wave tubes (TQWT), AKA tapered quarter-wave pipes (TQWP) and if you fold them up to 'tap' them, those few of us that promote them are calling them TTQWT or T-TQWT, so if you search this forum you should find some examples.

WRT these drivers being suitable for tapped horns, this is true in general, but like any box alignment you want the right driver specs for the app, so when you consider that Fs, Qts defines the driver's max tapped horn gain BW, the ones listed are best suited for true 'sub' duty where the TH's tuning length (Fp) is somewhat below Fs and bass/mid-bass duty in TTQWTs where typically Fp = Fs or higher.

GM
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Old 7th May 2009, 04:06 PM   #3347
Mark Kravchenko
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Default step response

The greatest difference between a SPL graph and a step graph is the information conveyed in the ability of the driver system/enclosure to reproduce a transient. The sharper the rise and fall the "quicker" the system. This is a function that is very dependant on voice coil inductance.

The ringing after the impulse are the box and driver trying to fall to a rest position. Obvious less is more here to.

Properly applied it is a very revealing test. It is akin to the resistance graph where all the wiggles relate to some kind of non-linearity.

I'm on a job site right now. But when I get home I'll post Joe D'Apollito's thoughts from his book on measureing loudspeakers.

What I know I learned from him!

Mark
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Old 7th May 2009, 04:26 PM   #3348
kees52 is offline kees52  Netherlands
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I resume that I am not dry behind the ears yet.

I do amps more often, but the box itself is still new for me, I have put the link there because it can maybe be of help.

I like the TH-Spud, but then as sub one of them in a stereo because it is efficient enough, and I can make a nice platform of it.

So one th-spub from 10 to 80 hz and then two bassmidd who I can hang on the wall, subtones unther 100 hz has no direction so it will have no impact on stereo.
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Old 7th May 2009, 05:14 PM   #3349
AndrewT is offline AndrewT  Scotland
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10 to 80Hz is three octaves.
Most tapped horns have a passband of 1.5 to 1.8 octaves.

Three octaves is about the limit of a front loaded horn that will be massive.
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Old 7th May 2009, 06:19 PM   #3350
kees52 is offline kees52  Netherlands
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oke thanks

dan I will go lower, it is not a problem.

the most difficult part are the sub-bas, and with a tapped
horn I can fill that.

only I will temper the Efficiency somewhat to get it equal with the bass-mid, I believe this can by make th mouth narrower..

regards kees
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