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Multi-Way Conventional loudspeakers with crossovers

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Old 16th August 2007, 06:16 AM   #1721
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Many thanks to you Lynn. I look forward to your successful completion of your project. I will be one of the many builders.

Best regards,
Bill
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Old 16th August 2007, 10:13 AM   #1722
lazenna is offline lazenna  Australia
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Don't know if anyone has looked at or used this woofer in OB but it looks like it may work very well. http://www.assistanceaudio.com/08_CIARE.html
18"
model 18.00NdW1 price** $210.00
weight 6.3 Kg vc size 100mm
size 18" Fs 29hz
power handling 500W (AES) Bl (Wb/m) 24.85
Vas (M3) 0.29643 Sd(M2) .115209
SPL 1w1m 100.5dB Qms 12.36
Xmax 7mm* Qes 0.32
Frequency 30hz-1khz Qts 0.31
magnetic induction (T) 1.2
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Old 16th August 2007, 11:20 AM   #1723
mige0 is offline mige0  Austria
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Default How to measure a driver for use as a dipole

Hi


keeping parameters constant during development allows for good pin pointing to unclear behaviour

(at least sometimes ).


Merging the simulation and measurements plots reveals that there is kind of comb filter superimposed to what is predicted by simulation at the first baffle peak and one or two octaves above


Click the image to open in full size.

What can be seen is that there is a interval of about 400 Hz. ( blue trace = simulation, black trace = measurement with no chamfer )




Yes JohnK, this irregularity may com from cavity resonance or additional diffraction at the speaker hole ( shouldn't be too difficult to add / verify this in your simulation sheet ) in the OB or both.
To some degree it can be smoothed out by simply chamfering the hole.

Click the image to open in full size.

What can be seen is that mounting the speaker ( same Peerless 6.5" as in post 1714 ) behind the baffle works better ( upper trace )

I think this is a nice little result of the method of cross correlating measurement and simulation as done in my last postings revealing that edge treatment is even of more interest close to the speaker ( nothing really new but often forgotten ) partly what Earl was pointing to several times


In contrast I remember a OB posted in this thread where is stated that a BIG cavity behind the speaker was made for improvement really would like to see the FR / CSD for this one.

Greetings
Michael


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Old 16th August 2007, 07:19 PM   #1724
jlo is offline jlo  France
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Quote:
So pink-noise is good for identifying peaks or more subtle buried resonances. It does not identify holes in the response - in fact, a quick A/B/A test might favor a slightly dished response over the flat one. It take a little experience not to be fooled by the "smoother" sound of a slightly dished response. As far as I know, narrow notches are not audible at all with pink noise
there is a real game here to play with peaks and notches in pink noise (or in music). You will learn or train to hear frequency anomalies but you may also have some fun !


Quote:
thanks for letting us know your software which I am sure is very interesting to many of us. I love to play with them but rarely have the time (I use internet only at work). I promise that someday I will. Before that happens, do you have a summary page in which you tell us your findings in your numerous software (even though it represents your personal opinions)? it would be extremely helpful.
Maybe I should do such a summary page but I prefer that everybody listens for himself.
I have followed the AES and other publications for many years and I was allways a bit frustrated to read about various audible phenomenas and, due to the needed expensive test gear, it was difficult to reproduce the experiments.
Now, with the power of computers and the ease to write quite sophisticated softwares, new types of tests can be implemented. And anybody can easily do the experiments at home and make his own opinion.
But if I do such a page with my own findings, I may call this page "accuracy or pleasantness ?"

regards
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Old 20th August 2007, 06:57 AM   #1725
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Many thanks, jlo, for your software page. Much appreciated!!!

Do any of these modules generate pink-noise, or is there a CD you can recommend that has high-quality pink-noise? (Truly random for at least several seconds, and accurate pink-noise filtering.)
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Old 20th August 2007, 08:09 AM   #1726
jlo is offline jlo  France
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Quote:
Do any of these modules generate pink-noise
quite all of my software integrate a signal generator with pink noise (you can choose between stereo correlated, uncorrelated or near critical bandwidth filtered ). They also generate sine waves, sawtooth, bonger,...
And if anybody has a good idea/need of a special audio signal, I can try to implement it.
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Old 20th August 2007, 04:21 PM   #1727
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Hi Lynn!

Didn't have the opportunity to read more than the start of this thread, but I wanted to add some comments... gotta roll out on a trip in a few mins, so the rest of the thread details will have to wait.

Horns.

The issues with horns are imho not where it is often assumed!
My views changed dramatically a few years back after a simple audition here in my system. Before that my view was that all horns are/were fatally flawed. Never heard one I really liked, and I had heard an awful lot.

My present view is that if the horn itself is what I will call "good" (proper termination, nil impedance discontinuities causing reflected energy, and the driver is properly loaded by the horn/waveguide) then the real determining factor is the compression driver itself!

Most, if not all of the negative auditory experiences with horns I think now is due to the compression driver's inherent flaws. Most are highly flawed, few are not so.

They're very very difficult to "get right."

So, if there is a direction to go in for horns it is to make the compression driver "better".

I think I have some compression drivers here that are at least an order of magnitude better than any TAD/JBL/Altec offering (that I have heard to date), and this makes all the difference in the world.

I get to run them with a single first order filter, and no EQ!
They measure scary well and flat. (obviously this would be the case if they were to be as good as I am saying)

This coming from someone who still owns large ESLs, and has owned SA tweeters (still extraordinary drivers) in his system, and who claims to have little difficulty hearing the difference between low distortion opamps in his DAC (for example)...

Someone mentioned orchestral music? Large choral pieces? Cake walk for the present horn system here - loads of space, resolution and extreme naturalness. Even if I do say so myself.

More "jump factor" than anything else I have ever heard - as do most good horn systems, but without any "horn sound".

Perhaps the view on horns needs to be revisited starting from the diaphragm of that compression driver and working out and back from there.

_-_-bear
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Old 20th August 2007, 09:10 PM   #1728
ScottG is offline ScottG  United States
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Quote:
Originally posted by bear


I think I have some compression drivers here that are at least an order of magnitude better than any TAD/JBL/Altec offering (that I have heard to date), and this makes all the difference in the world.

I get to run them with a single first order filter, and no EQ!
They measure scary well and flat. (obviously this would be the case if they were to be as good as I am saying)



_-_-bear
Well good lord man.. spill the "beans" - what compression drivers?
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Old 20th August 2007, 09:25 PM   #1729
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Default Maybe

they are Japanese ALE compression drivers. Those make TAD look cheap.
C
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Old 20th August 2007, 09:26 PM   #1730
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Quote:
Originally posted by ScottG
Well good lord man.. spill the "beans" - what compression drivers?
More details such as the flares used etc would be great. Thanks.
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