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#581
PB2 said:
I'm being quoted out of context here, this is pathetic. If you are going to comment on my posts try to read and understand exactly what I am saying rather than take it out of context so that you can appear to be correcting me.

You seem to have assumed that I used a lumped model in my paper, I did not as I stated earlier in this thread.
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I wasn't disagreeing with you.
I wasn't trying to correct you.
I made no assumptions about your paper.

I was trying to clarify what I meant in my earlier post, and point out that what I was trying to say was in complete agreement with your earlier posts.

I also agree with everything you said about modeling in your last post.

Perhaps we can agree to agree?
🙂
 
#582
godfrey said:
I wasn't disagreeing with you.
I wasn't trying to correct you.
I made no assumptions about your paper.

I was trying to clarify what I meant in my earlier post, and point out that what I was trying to say was in complete agreement with your earlier posts.

I also agree with everything you said about modeling in your last post.

Perhaps we can agree to agree?
🙂
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It didn't sound like it, but good, let's agree then!
You also agree with Gedees who is wrong about the first resonance in a TL,
even if you approximated it with lumped parameters which I am not suggesting
the first resonance would in fact be the one modeled.

Referring to T&S type analysis which uses lumped parameters for traditional
systems it sounds as if you are suggesting there is a better way, please tell us
what it is if so.
 
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#585
godfrey said:
can't self-quote as my earlier post was deleted, but I think Earl summed it up quite nicely here:
Quote:Originally Posted by gedlee
Lets please remember that these "circuit" type analogies are limited to LFs. Even at the first resonance of the TL these electrical circuits analogs are no longer valid.
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And this I disagree with, again, never was talking about a lumped TL model and no matter how you try to interpret Geddes' statement it is plain wrong.
 
#586
MJK said:
OK Ed, how about telling us more about the designs that produced those two very different SPL curves using the same driver. I have to admit I have not seen anything like that before and would be interested in more details.
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Martin,

There is an analogy to the extended bass shelf vented type design.
Take a driver with a high Fs say 50 hz and tune in the 30s, adjust the box size to adjust the output at Fb. The response will shelf down and be a fairly good match for room gain as I pointed out probably 15 or more years ago on the Bass List:
The Subwoofer DIY Page - Extended Bass Shelf systems
 
#587
tinitus said:
I expected it would look strange
No, completely closed

Closed mass loaded pseudo TL🙄

I will see if I can spot a good woofer
Which direction to take it depends on whether it works and how

If at best, low bass with low Qts driver, and still being a closed system
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There is a discussion of a closed TL that presents a mass load to a driver as far back as Beranek, probably further but it was a simple pipe not your construct. You will get no port augmentation obviously, so a high Xmax driver would probably be best. I've never tried to model this type of system.
 
#588
Interesting post by Ken Kantor:
AudioKarma.org Home Audio Stereo Discussion Forums - View Single Post - Fact from Friction

"A- In no area of audio is the chattering of internet groups in any way, shape or form indicative of the true state of knowledge of actual industry experts. Almost all industry professionals avoid the internet like the plague, for exactly this reason. Internet debates are to the audio biz, what bar fights are to the Olympics."

He also states: "D- The relevance of, "transmission lines," is exactly what? What do they do well that is important to loudspeakers? Who still uses them?"
Bose still uses them and makes a lot of money at it!

The OP was shut down at AK also.
 
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#591
PB2 said:
Referring to T&S type analysis which uses lumped parameters for traditional
systems it sounds as if you are suggesting there is a better way, please tell us
what it is if so.
Click to expand...
No, I think lumped parameter modeling is great for sealed boxes, reflex systems and the like.

It's just with transmission line enclosures (and horns, for that matter), where the internal path length is long, that transmission line modeling is more appropriate (using T/S parameters for the driver, of course).

Sometimes the boundary can be a bit blurred. For example a very tall reflex box would be better modeled as a transmission line, but I gather those sorts of enclosures are referred to nowadays as "mass loaded transmission lines" anyway.

While tapered transmission lines and horns look quite different and have separate groups of enthusiasts, the same software modeling techniques ought to be applicable to both.

It would be interesting to compare results between e.g. Hornresp and Martin's TL software when faced with the same speaker design.
 
#592
godfrey said:
No, I think lumped parameter modeling is great for sealed boxes, reflex systems and the like.

It would be interesting to compare results between e.g. Hornresp and Martin's TL software when faced with the same speaker design.
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I put a vented design into Hornresp and it was way off as far as box size required to match the same design modeled in Unibox which I trust. My intent was to show that similar, if not better, responses to some of the unusual so called tapped horns or derivatives could be obtained with simple, smaller, vented systems. I tried hornresp in order to use the same simulator that the OP used and in order to see if the two simulators agreed:
AudioKarma.org Home Audio Stereo Discussion Forums - View Single Post - AK Design Collaborative - Insubnia

I don't know exactly what this "unhorn" is trying to claim to be, but I also did a comparison
to a traditional vented design in the same size box here. While the OP was showing big SPL
numbers the design was not significantly more sensitive than the traditional vented box. This
isn't exactly a traditional box since the port is about 30" long IIRC so there is some transmission
line behavior visible here:
http://www.hometheatershack.com/for...-trio8-unhorn-proof-concept-3.html#post208496

There are a lot of wild claims being made for these new tapped horns and I am interested in comparisons as a sanity check.
Generally if there is not a long slow taper ending in a large mouth it is not a low bass horn, lol!
I actually view many of these new designs as more like a TL derivative than a horn.
 
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#596
PB2 said:
I put a vented design into Hornresp and it was way off as far as box size required to match the same design modeled in Unibox which I trust. My intent was to show that similar, if not better, responses to some of the unusual so called tapped horns or derivatives could be obtained with simple, smaller, vented systems. I tried hornresp in order to use the same simulator that the OP used and in order to see if the two simulators agreed. This
isn't exactly a traditional box since the port is about 30" long IIRC so there is significant transmission line behavior visible here:
AudioKarma.org Home Audio Stereo Discussion Forums - View Single Post - AK Design Collaborative - Insubnia

I don't know exactly what this "unhorn" is trying to claim to be, but I also did a comparison
to a traditional vented design in the same size box here. While the OP was showing big SPL
numbers the design was not significantly more sensitive than the traditional vented box:
TRIO8 "Unhorn" Proof Of Concept - Page 3 - Home Theater Forum - Home Theater Systems - HomeTheaterShack.com

There are a lot of wild claims being made for these new tapped horns and I am interested in comparisons as a sanity check.
Generally if there is not a long slow taper ending in a large mouth it is not a low bass horn, lol!
I actually view many of these new designs as more like a TL derivative than a horn.
Click to expand...

Above post edited to fix a previous edit.
 
#599
PB2 said:
I put a vented design into Hornresp and it was way off as far as box size required to match the same design modeled in Unibox which I trust.
Click to expand...
Oops, interesting!

I'm not too enthusiastic about tapped horns either. When I see huge response peaks in the upper bass and lower mid, that immediately tells me that efficiency down in the "FR shelf" region is far from optimum.

The performance only looks impressive until you compare it to a large, properly designed (and preferably front-loaded) horn.

btw, I enjoyed your little calculation showing that 115dB(!!!) @ 400W = only 89dB @ 1W sensitivity. 😀

I don't see "Big, Load, Low - pick any two" changing anytime soon.
 
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