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Multi-Way Conventional loudspeakers with crossovers

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Old 13th June 2008, 05:04 PM   #3951
badman is offline badman  United States
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Default Re: Re: Good Articles

Quote:
Originally posted by mige0



Lynn, having also worked with large PA horns, my findings are slightly different from yours.
I agree that there might be some brute force sensation coming along with that beasts but I trace down the underlying aspects differently.

- the effortless presentation I assume to be a side effect of low thermal transients = BIG voice coils.
- the sensation of "bigness" I assume to be the same like from line arrays = the room angle covered by the source.
- going up "endlessly" in SPL is just that it usually is like that (at listening room distances) due to high efficiency and usually extend excursion designs.
- some of the "lifelike clarity" I assume to be due to low Doppler IM with large radiating areas

Put one or two 15" besides your Ariel and cross at around 300-500Hz � I'll bet, you'll experience the sensation you are heading for (within the limits of the Ariel drivers).



Greetings
Michael
Not just the big voicecoils, I think much of what makes prostyle and/or high efficiency and/or fullrange drivers so involving at low levels is probably due to the high Qms. Less memory effect in the materials, and the driver controlled more by the motor.
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Old 13th June 2008, 05:26 PM   #3952
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Quote:
Originally posted by Jmmlc
Hello,

There is no silly questions only silly ******s. ;-)

From an historical point of view, to my knowledge, the increasing directivity of horns were never used as an argument to the "3 octave question"...

Most often the upper limit of the power response is one of the arguments.

If we use the empirical (again) formula for the lower frequency limit Fl and for the upper frequency limit Fh (see JBL technical paper http://www.petoindominique.fr/pdf/JB...-frequency.pdf )

Fl = Fs . Qts / 2 and Fh = 2 . Fs / Qts

Generally compression drivers are used above the resonance frequency of the (loaded) loudspeaker Fs with horns having quite the same cut off frequency: Fc ~= Fs . (well if you use an Altec 802 it can be different due to high Fs...). This means that for a horn loaded compression driver we have to consider as the bandwith the frequency interval between Fs and Fs/(2 . Qts).

A rapid calulation will indicate that Fh = 8. Fs (3 octave bandwith) for Qts = 0.25. I let you know if this is relevant in your case...

This is for the power response. Power response is very important when you have to design folded bass horns by example (see Marshall leach and others).

But is it important for straight horns? Your own taste can lead you to reply YES if you prefer the horn or the waveguide to have a response similar in shape to the power response. My own answer will be NO , I don't want my driver + horn equalized and my preference for music recorded in phase stereophony lead me to listen alone at the sweet spot on my main system so I don't care so much about the off axis response (if the reverberated field is OK to those ears).

To my knowledge there is no compression driver for which the upper limit of the power response as mesured on planar wave tube is over 4kHz or such. Does this means that the compression driver cannot reproduce 18kHz? No, see on axis response for an unaqualized TAD TD2001 driver on a Le Cléac'h horn as a good example.

Have a good week-end.

Best regards from Paris, France

Jean-Michel Le Cléac'h






Whatever- I know I answered your previous question regarding 3+ octaves and certainly I made my point.
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Old 14th June 2008, 12:10 AM   #3953
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Default Re: Re: Re: Good Articles

Quote:
Originally posted by badman


Not just the big voicecoils, I think much of what makes prostyle and/or high efficiency and/or fullrange drivers so involving at low levels is probably due to the high Qms. Less memory effect in the materials, and the driver controlled more by the motor.

In non ferrofluid drivers the low Qms is coming from an aluminum voice coil former of which I never heard or measured a difference. Very little of the suspension comes into play for the Qms (actually the correct spec for this effect is the Rms)
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Old 14th June 2008, 05:22 AM   #3954
dmason is offline dmason  United States
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Nice to see Master-Bates is once again, among us.
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Old 14th June 2008, 12:02 PM   #3955
SunRa is offline SunRa  Romania
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Hello Lynn,

any reason you've excluded the 12" alnico TT's form your review? It think they are in the same price range with the rest of the drivers you intend to listen and they have the same sensitivity figures also...

Thank you!
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Old 14th June 2008, 08:11 PM   #3956
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Lynn, et al,

Your design is quite intriguing, and I continue to follow this thread daily (at least!).

As it has developed I have enjoyed learning about the various drivers under consideration and it has lead to lots of fun research/thinking of my own.

The re-mention of the 6ND410 a few posts ago leads me to some thoughts that I hope aren't perceived as too far off-topic.

As you outlined, the appeal of a large MR driver is compelling (i.e. my unused JBL 2123's or the 10" 18sound MR units that have been discussed). My question is, in general, as part of overall system design, whether you (or others) believe in theoretically ideal XO points (or conversely, XO frequencies to be avoided). As an example, Colloms, in his book (and others) recommend as theoretically ideal the avoidance of a crossover in the ~300-to at least 3k (and preferably higher) range. Your horn choice obviously crosses a bit higher at the low end but allows the next break-point to the RAAL to be nice and high (and your previously-demonstrated skill in crossover design will certainly be of great help in your efforts).

Modelling of the 6ND410 suggests that in a baffle large enough to maintain 2 pi radiation to its lower crossover point (at least 300Hz and perhaps even 250Hz) that it could reach 120db (as a single unit) well within 2mm of excursion. While realizing that radiation pattern isn't your top design criterion, this unit could (by my preliminary/theoretical/non-measured calculations) match the XT1086's horizontal 80 degree radiation pattern at 3- 3.1 kHz and maintain high overall system sensitivity. It could also be crossed over to the larger (not double-high) RAAL unit at this level (while obviously not matching radiation pattern or as high overall system sensitivity).

I thought a bit about 2 vertically-aligned 6ND410's to match a bit better the horizontal dispersion of the large RAAL ribbon, but suspect that the driver-to-driver spacing of the 6ND410's would introduce combing if the higher crossover frequency was used, again forcing the XO frequency lower.

Any thoughts?

Sincerely,

Bill
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Old 14th June 2008, 11:21 PM   #3957
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Quote:
Originally posted by Bill Brown
Lynn, et al,

Your design is quite intriguing, and I continue to follow this thread daily (at least!).

As it has developed I have enjoyed learning about the various drivers under consideration and it has lead to lots of fun research/thinking of my own.

The re-mention of the 6ND410 a few posts ago leads me to some thoughts that I hope aren't perceived as too far off-topic.

As you outlined, the appeal of a large MR driver is compelling (i.e. my unused JBL 2123's or the 10" 18sound MR units that have been discussed). My question is, in general, as part of overall system design, whether you (or others) believe in theoretically ideal XO points (or conversely, XO frequencies to be avoided). As an example, Colloms, in his book (and others) recommend as theoretically ideal the avoidance of a crossover in the ~300-to at least 3k (and preferably higher) range. Your horn choice obviously crosses a bit higher at the low end but allows the next break-point to the RAAL to be nice and high (and your previously-demonstrated skill in crossover design will certainly be of great help in your efforts).

Modelling of the 6ND410 suggests that in a baffle large enough to maintain 2 pi radiation to its lower crossover point (at least 300Hz and perhaps even 250Hz) that it could reach 120db (as a single unit) well within 2mm of excursion. While realizing that radiation pattern isn't your top design criterion, this unit could (by my preliminary/theoretical/non-measured calculations) match the XT1086's horizontal 80 degree radiation pattern at 3- 3.1 kHz and maintain high overall system sensitivity. It could also be crossed over to the larger (not double-high) RAAL unit at this level (while obviously not matching radiation pattern or as high overall system sensitivity).

I thought a bit about 2 vertically-aligned 6ND410's to match a bit better the horizontal dispersion of the large RAAL ribbon, but suspect that the driver-to-driver spacing of the 6ND410's would introduce combing if the higher crossover frequency was used, again forcing the XO frequency lower.

Any thoughts?

Sincerely,

Bill

I know the 6" will be strained regardless of the specs/modeling

I have a three way solution I built that is very (ultra) low compromise

I will start another thread
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Old 15th June 2008, 03:42 AM   #3958
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Quote:
Originally posted by Magnetar
I have a three way solution I built that is very (ultra) low compromise

I will start another thread
I am looking for this thread but have not found it yet. When you post it, will you please put a link into this thread?
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Old 15th June 2008, 05:31 AM   #3959
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Quote:
Originally posted by Charles Hansen


I am looking for this thread but have not found it yet. When you post it, will you please put a link into this thread?

My daughter nabbed my camera so I 'll have to post a pic when I get it back - I'll start a thread then

It's an open baffle with no wings and a little eq on the bottom - nice and compact (for me at least)

It's triamped with the KILLER Beyma 21L50 21" woofer up to 150 cycles then for mid is a modified Electro Voice SRO12 with the 'coffee can' alnico magnet. For 1500 up it is the alnico Emilar EA175 1" compression driver with aluminum diaphragm/mylar surround loaded in a really trick horn I found- the Renkus Heinz Complex Conic CCH12009 round horn. No tweeter needed.

My goal was high efficiency open baffle 3-way with bass into the 30's and mid crossover below 200 cycles - tone was also at the top of the list - It does it well..Complex Conic Horn
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Old 15th June 2008, 07:30 AM   #3960
SunRa is offline SunRa  Romania
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This complex conic horn looks a bit like Dr's Geddes waveguides, isn't it? Magnetar, can't wait to see your new loudspeakers!
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