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Old 7th May 2008, 06:25 AM   #3501
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Quote:
Originally posted by Charles Hansen
in my estimation the TADs are overall better than the K2's. But if you didn't like the TADs, I'm not sure you will like the K2's any better.
The TAD 1 plywood ribs screw_rods + glue stack-up showing extensive bracing and box resonance control.
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File Type: jpg stackuptad.jpg (54.6 KB, 1092 views)
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Old 7th May 2008, 06:27 AM   #3502
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The TAD 1 plywood ribs screw_rods + glue stack-up showing extensive bracing and box resonance control.
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File Type: jpg tad1cabinetinterior.jpg (31.6 KB, 1070 views)
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Old 7th May 2008, 07:21 AM   #3503
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The TAD Model 1 is no longer in production. In fact there were only a handful of prototype pairs ever made. The current model is called the Reference One and does not use the same method of cabinet construction.
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Old 7th May 2008, 07:23 AM   #3504
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Quote:
Originally posted by LineSource
The TAD 1 plywood ribs screw_rods + glue stack-up showing extensive bracing and box resonance control.
Also, be aware that the "box resonance control" you are talking about is not the same issue that Lynn brought up in his post.
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Old 7th May 2008, 09:03 AM   #3505
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Default Re: Re: Measurements, and PHL 1120 as a midrange

Quote:
Originally posted by SamL


PHL 1220 driver question
Old post with brief comment on PHL1120, more on Audax PR170M0.

Thanks for that. What puzzels me is that quite a few seem to like and praise the PHL 1120 (Aleksandar from RAAL, Nelson Pass) despite what looks (to me at least) as irreparable cone breakup around 3k.

Regarding measurements, the first one posted seems to be the standard 1m measurements whereas the one I posted is taken in nearfield at 1''.

However, things seem to correlate: In the second graph there there is a glitch in the impedance response at the same point

How does that cone breakup sound when the PHL is XOed (4th order LR, as most seem to do) at 2.5k would be very intresting to hear (with no tweet).

Thanks for the link,

Florian

P.S. The Audax seems not much better either. Take a look at the CSD: http://www.cadaudio.dk/pr170m0.pdf
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Old 7th May 2008, 09:06 AM   #3506
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Yes, the "box modes" I was speaking of would occur in an infinitely rigid box - think of it as room modes writ small, or rather, happening at frequencies about ten times higher. Unlike room modes, though, these standing waves compete with the characteristic sounds of wood-box instruments, such as violins, cellos, and pianos. They screw up the timbre of these instruments and add an unnatural - well, "boxy" sound to vocals.

This particular coloration tends to go unnoticed since it is so common - it's the generic sound of table radios, TV sets, just about everything. Audiophiles put up with the problems of electrostats and magnetic-planars just to get away from the annoying box sound - but then accept serious dynamic-range restrictions "as the price they must pay" to avoid box colorations. This choose-one-or-the-other dichotomy, which has existed since the days of the Quad ESL57 and the KLH 9, has bedeviled the audio community for decades.

High-efficiency dipoles can offer a way out. There are still plenty of challenges - increasing dynamic range in the bass is the most obvious one - but it is an alternative that bridges the gap between electrostats and large-format studio monitors. You have to give up the idea of a compact little speaker that is apartment-friendly, but you have to do that anyway if you want wide-range dynamics. As the designer of one of these cute little speakers, I am all too aware of the dynamic-range restrictions of this genre of loudspeaker.

Aside from decor-friendliness, one of the technical advantages of mini-monitors (or nearfield monitors, take your pick) is a box size where the colorations occur at a higher frequency than the traditional studio monitor - and at frequencies where box linings actually start to work successfully. Thus, the "crisper" sound of the little monitors.

The B&W Nautilus was a clever attempt to control the box modes by forcing the backwave into lossy tapered transmission lines, but then problems with resonant modes in large areas of fiberglass arise - no free lunch here either. And don't believe all you read about magical damping properties of this or that damping goo, damping pads, this that or the other - getting just a few dB of attenuation out of these magic materials is a big challenge.

The proof, as always, is in the measurements and listening. The trick with measurements, of course, is getting some degree of correlation with what you hear - and what to listen for.
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Old 7th May 2008, 06:56 PM   #3507
mige0 is offline mige0  Austria
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Quote:
Originally posted by Charles Hansen


All I can tell you is that CSD (waterfall plots) are not a very good way to examine the behavior of the diaphragm. They will show very gross problems, but are completely unable to show more subtle problems.


Well all too true.

My point on this one simply is that speaker industry first has to solve the gross problems - like cone breake up and fast decay over a wide frequency range - all too visible at CSD's.

- no need for DOS based MLSSA since there is the user friendly ARTA - thought you still have to accept the 1/12 octave smoothing in the current (freeware) version.
- no need for big rooms
- no need for long windows
- no need for anechoic rooms
- no need for outdoor measurement.

(True only for the range of 300Hz up of course)

Why doesn't it spread more?
Well speaker industry isn't really interested in pictures where "Mr Anybody" can point with the finger on gross defects.
But why don't we see it more in the DIY community? Use the DiyAudio search engine and type in CSD - you get barley 1000 hits .
Even worse - out of that 1000 most are just talking no "hard data" .

It's simply because there still is that nimbus on that it is sooo complicated to do and sooo complicated to interpret.


- no it is NOT


At least for breake up resonances (and some other defects) applies: "If it walks like a duck and quacks like a duck, then it is a duck."


Only ONE single page on the whole www I am aware of that consequently displays CSD: ZaphAudio

WHAT a PITY

Quote:
Originally posted by Lynn Olson

The proof, as always, is in the measurements and listening. The trick with measurements, of course, is getting some degree of correlation with what you hear - and what to listen for.

All too true.

- no need to produce "perfect" measurements ist's just a waste of time and you NEVER ever will succeed no matter on how high tech equippment you use the best measurement one can do are the one's that serves the process of learning individually or collectively.


Greetings
Michael
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Old 7th May 2008, 07:27 PM   #3508
mige0 is offline mige0  Austria
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Quote:
Originally posted by Lynn Olson

The B&W Nautilus was a clever attempt to control the box modes by forcing the backwave into lossy tapered transmission lines, but then problems with resonant modes in large areas of fiberglass arise - no free lunch here either. And don't believe all you read about magical damping properties of this or that damping goo, damping pads, this that or the other - getting just a few dB of attenuation out of these magic materials is a big challenge.

From some own measurements I can tell there is VERY little effect on the concept of the Nautilus box shape concerning dampening modes I doubt it can be called a (lossy) transmission line concept at all.
No DIY projects I am aware of that report / verify a break through.

Well its beautiful and at least an outstanding design and CLEVER marketing of course.


Greetings
Michael
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Old 7th May 2008, 10:59 PM   #3509
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Quote:
Originally posted by Lynn Olson
By the way, I'd like to thank John Janowitz for the information and graphs on the AE Speaker Lambda TD-15M. That certainly look like a contender - let me know if you're considering Alnico, that would make it even more attractive, and would justify a higher price. (I can't believe I just said that!)

In my experience, Alnico isn't so much about adding a guitar-friendly coloration, but more about noticeably better rendition of instrumental subtleties and a more palpable, in-the-room quality to the instruments - a palm sliding across the surface of a drum, the sound of wood in the cello, more vivid tone colors that sound less artificial and more real. The difference is most apparent in the 200 to 1 kHz region, from what I heard.

In the amplifier world, this isn't a clever type of coloration you can add, but more a matter of reduction of distortion, or an improvement in a power supply. Alnico does something better, and I don't know what it is, although my guess is something to do with back-EMF's induced in the magnet structure. It does sound very much like better core materials in audio transformers, for those of you who have auditioned different transformers.

I looked at Alnico sometime back and learned that the thick copper tube I used in the TD driver design acted alot like Alnico did. Alnico from what I remember kept the inductance lower and also didn't allow the stationary gap flux to be moved by the "temporary" magnetism of the voice coil. Its been years and I forget many of the details for this. We even looked at testing a field coil version as that is supposedly the best magnetic field that can be made.

If you wanted Alnico it can be done but I imagine the price tag would be outrageous for 99% out there as you need a massive amount of steel to complete the circuit. Plus a large enough chunk of Alnico isn't cheap either.

Nick McKinney
(he's back)
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Old 8th May 2008, 12:30 AM   #3510
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Quote:
Originally posted by nickmckinney
Nick McKinney
(he's back)
Welcome back, Nick!

I never got a chance to thank you for those wonderful drivers you made for me a few years ago - so... Thanks!

Hope you enjoy your stay!
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