Aleksandar Radisavljevic on RAAL speaker

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#21
How should you employ a cluster of 3" FR's for mids?

Hi Alexander (and others),

I have been very intriqued by your (Alexander’s) idea of using a cluster of 3” drivers for mids. In a previous mail you stated that you did not want to comment on other specific 3” drivers that might, or might not, be suitable for the “cluster” approach. I fully understand that of course. I am just very pleased that you gave a detailed account on how such a 3” FR driver should be!

Doing a few searches for 3” drivers I have come across the 3” Faital Pro 3fe20 ‘fullrangers’ (see attachment). This driver actually seems to fulfil all the requirements you stated(!):

• Central pole piece
• A voice coil former made of kapton
• High Qms (=5)
• No use of faraday ring(s)
• No major impedance peaks in the 500-3000 Hz range.
• Paper cone

Besides, the driver is highly efficient for a 3” FR (91 dB/1watt), has low Le, and finally, it’s not even expensive!

I seriously consider trying a cluster of these as midrange devices. I am not asking you to comment on the driver, but I would be really pleased if you would look at the questions below with regards to how to employ such a cluster a mids:

1. I consider using 3x4, 3x5, or 4x4 drivers per channel in order to reach sufficiently high efficiency. Are there any drawbacks of going beyond the 2x4 or 3x6 as you suggested (e.g., will the mids get ’un-focussed’ if the cluster gets too large?)

2. Would you recommend the cluster of drivers mounted on an open baffle, OR in a sealed chamber?

3. How far down in frequency would you recommend to use such a cluster for home use? (Note: I will probably use a 24dB/octave active filter for high pass, but like to play loud at times!)

Thanks a lot in advance!

Best regards
Peter
 

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#22
3) no Faraday ring(s)
Click to expand...

+1 to CLS.

Alexander, I'd like to hear more about why "speakers with Faraday rings sound boring anyway." You state this categorically, but then you make no specific mention of how shorting rings cripple performance, other than briefly mentioning heat. You outline a case for there being no need of them with proper motor design, but not why they are specifically bad.

In other words, your assertion seems to be be akin to: "drivers with a piece of chewing gum stuck to the basket sound boring." But why?

Not looking for a fight, just seeking new light.
 
#23
Hi pk, thanks for sharing, that's a good find.

I once saw a strange but interesting speaker in a restaurant:

0034.jpg


One might say there'd be a lot of messy lobings... etc.

What the heck, that's fun, at least 😀 Oh, uh... but actually I didn't hear it play anything TBH. I guess it should be OK far field...
 
#24
Pity that RAAL seemed not knowing this thread (or not willing to post here)?

Nevertheless I found another very interesting post here:

Originally Posted by RAAL

Originally Posted by Elias
Hello all,

That is the old fashioned engineering point of view but unfortunately it does not make any psychoacoustical sense. What we really need is monotonically widening dispersion somewhere above 3kHz. To minimise the cross talk artefacts of stereo one needs to spatially homogenise the pinna cues and that is most easiest done by providing very wide dispersion at treble, almost omnidirectional above 3kHz.

Also in the midrange below 1kHz one needs to minimise room reflections to be able to provide stereo ITD cues and that is best done with very narrow dispersion.

Clearly it turns out the ideal loudspeaker directivity is not constant, not narrowing but widening!

This radical view was offered for your pleasure by Elias
Click to expand...

Since I share this view to the last point, that's why I can't really figure out what would be the benefit of having equal dispersion everywhere, as both rooms and our psyche doesn't accept it equally.
As I pointed out before, all rooms have problems in bass, and some rooms have problems in presence region (centered about 2k5). As cuibono pointed out he prefers dipole at least up to 4k, which falls in line with mentioned room problem.

I just want to add that I stand behind the room treatment and prefer omni down to 200 Hz in such case. Rooms must be treated, or they will ruin a lot of our efforts. However, once appropriately treated according to their size and volume, the results are nothing short of astonishing and the sound is in a different class altogether. Nothing like it, if you want to hear the actual size and feel of the instruments, and horns can't touch it, with their "in your face" presentation. The way I like to put it, they have a big sound, but not big instruments.

One of the people from the whole of audio industry that I admire the most is Amar Bose. He went through the trouble of designing excellent 5" whizzer-less FR drivers and stuffed 9 of them in a clever box, with one shooting forward.
That speaker, with it's dedicated EQ box, kicks *** big time in recreating the proper size of the orchestra and all that it contains.

For me, a wide baffle, big midrange (even 12"), OB is the next best thing in untreated rooms.
Click to expand...

I found the last sentence the most interesting to me 😀

I have an untreated room, and can't make an omni down to 200Hz, so I'm in the group that can only pursue the "next best thing".

Interestingly, I myself have had tried 12" midrange on a 3ft wide OB !! Maybe something wrong with my setup, I might say it sounded very good, but it's not at the 2nd place in my mind.

Hmm.....

Any comments? 🙂
 
#25
CLS said:
Pity that RAAL seemed not knowing this thread (or not willing to post here)?

Nevertheless I found another very interesting post here:



I found the last sentence the most interesting to me 😀

I have an untreated room, and can't make an omni down to 200Hz, so I'm in the group that can only pursue the "next best thing".

Interestingly, I myself have had tried 12" midrange on a 3ft wide OB !! Maybe something wrong with my setup, I might say it sounded very good, but it's not at the 2nd place in my mind.

Hmm.....

Any comments? 🙂
Click to expand...

Hi CLS,

As you can imagine, I would also appreciate to hear from Raal, but on the other hand I can see that it is not easy for manufacturers to participate in such forums.

May I ask what 12" you have been using in an open baffle?

Thanks!

Best regards
Peter
 
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