[tino84]

this is a post of mine on another forum..

http://www.tforumhifi.com/t10159p870-nxt#349143

I just unmounted a Monacor Ar-30 

[zygadr]

You mean you took one apart?................and.................... ....so what????

[tino84]

just to let you know how's made a Monacor (and I think also Visaton bs76).

see photos in link I posted 

[el`Ol]

http://www.hrl.com/hrlDocs/pressreleases/2011/prsRls_111117.html

[bobloblob]

Very, very interesting stuff.  I think its energy absorbing qualities might make it less than optimal as a sound-transmitting panel, though.

Several years ago there was a lot of r&d going on with materials based on silicon rather than carbon at their hearts, but I haven't seen anything lately.  There was one material that was supposed to be lighter than air (they demonstrated it floating in a terrarium of air), and another that absorbed heat - it was a foam that broke down when a flame passed over it, absorbing the heat energy in the process.  Another product was an edible foam coffee cup.

These material science guys have come up with some amazing stuff.  Wish more of it would come to market in a way that would be usable to us.  I guess the cost/benefit/profit monster stops these things, certainly at the individual consumer level - for instance, Nomex for the small buyer.

[el`Ol]

Looks a bit like space-travel only stuff.

[bobloblob]

Something that I always thought might have DIY potential is a product called micro-spheres.  Fifty years ago we used it, mixed with polyester resin, to fill dings in surfboards.  It's extremely lightweight, being only a thin shell of glass encapsulating air, and each bubble is tiny (hence "micro").  One should wear a respirator when working with it, as the spheres, almost powder-like, tend to float in the air a bit.  With a decent binder, maybe epoxy rather than polyester, it may produce a panel both reasonably rigid and strong, or maybe this combined with a very thin carbon fiber fabric.  Beyond my abilities, however.

[nigretti]

Visaton ar 50 don't sound bad and have a good power limit. The problem i find is that they sound loud, sometimes louder than then the panel itself. This give a nasal sound localized in the exciter and not in on the panel. A second sound source in the rear, sometimes louder the the first (the panel) I use gatorfoam 4mm, 40x50cm With dayton this don't happen, they disappear in the panel. Using gatorfoam 80cm x80 the problem is the same.

[zygadr]

Perhaps the AR-50 requires a panel that has higher self dampening ..........such as thin plywood ?

It is obvious that the AR-50's motor is far more powerful than the Dayton/Chinese type. It's also possible that the Monacor is approaching a ''shove force'' that is similar to the ''bass shaker '' variety which need to be mounted to very solid and dense surfaces to work properly.

These are only theories, but we may need to test the AR-50 with far denser panels compared with what we have been using in the past.

[Abelma]

[

[mkstat]

Hi all!

There are some new exciters available from HiWave at Parts Express:

http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=634


 - the most interesting one is the HiWave HIAX32C20-8 32mm Self Supported Exciter.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=297-2114

Although it has a power rating of 30W rms I doubt it is the best choice for low frequency reproduction because of restricted excursion capabilties due to its mechanical design. Nevertheless I think it's a big step in the right direction - especially regarding cost effectiveness.

I've also performed extensive tests on the AR-50 during the last months - in my opinion  it is no match to the HiWave exciters - soundwise and also regarding sensitivity - however their rugged, waterproof design offers some interesting ways of use. 

Another interesting design I came across is the following:
http://usfps.com/mcma-transducers_en.html

The FPS0105HY-02 hybrid speaker seems to be an interesting tool

regards
-m

[zygadr]

Hi all!

There are some new exciters available from HiWave at Parts Express:

http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=634


 - the most interesting one is the HiWave HIAX32C20-8 32mm Self Supported Exciter.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=297-2114

Although it has a power rating of 30W rms I doubt it is the best choice for low frequency reproduction because of restricted excursion capabilties due to its mechanical design. Nevertheless I think it's a big step in the right direction - especially regarding cost effectiveness.

I've also performed extensive tests on the AR-50 during the last months - in my opinion  it is no match to the HiWave exciters - soundwise and also regarding sensitivity - however their rugged, waterproof design offers some interesting ways of use. 

Another interesting design I came across is the following:
http://usfps.com/mcma-transducers_en.html

The FPS0105HY-02 hybrid speaker seems to be an interesting tool

regards
-m

mkstat, I agree absolutely with you on this particular exciter .
 The 32mm voice coil(the largest currently available) allows significantly more power to be applied to the exciter, and when wired in series/paralell etc. the overall power handling should be sufficient for most of us...........even in the bass department.
If you look at the other exciters some start at 11mm diameter voice coils( )up to the old standard 25mm that most of us have already used. So, the 32mm type is a VERY interesting contender at the moment.

It is also ''self supporting'', so there will be no problem with ''voice coil droop''.

I think this is the one to go for towards the next stage of NXT panel experimentation

[Abelma]

T

[mkstat]

This is self supporting also, 32 mm voice coil diameter, and long excursion
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=297-224

Good find! I did not recognize this one because it looks the same as the Dayton Audio DAEX32 Balanced Exciter 32mm which has only a power rating of 10W rms. Nevertheless i suspect its suspension system is rather stiff.

@ zygadr:

I would not underestimate those little 11mm exciters - seriously 0,5W rms is not so bad keeping the size in mind - they allow for only 25mm center to center spacing - in a line array arrangement and have 32 ohms impedance - so its possible to wire up 8 in parallel for a 4 ohm total impedance. They also seem to be "balanced" (at least the HiWave HIAX11C005-32/LP 11mm Low Profile Exciter) - this is a big plus regarding reliability and will prevent "thumbling" at higher excursions and hence reduce distortion in comparision to the not balanced ones. Imagine a 1.6m or taller panel with 64 of these exciters in series parallel wiring. This will be as close as you can get to a real continous line source with single exciters - serious side lobes will start in the range above 10khz and powerhandling will be 32W rms in total. Using the right panel properties for these little suckers (quite thin, not too stiff) could improove several high frequency problems in comparision to former designs substatially and also could boost efficiency (also due to less spl drop per distance doubling) so that the power handling capability will be less of an issue. According to my experiments with close exciter spacing it will also bring the soundstage more in front, right in your face because the nearfield is extended not only for the lower frequency range (large panel with several evenly spaced exciters), also the higher ones - remember the very good paper of Mr. James Griffin on Near Field Line Arrays posted some time ago here in this thread. Most of the principles do definitely apply for this kind of transduction althoug the close coupling of the drive units complicates the whole thing a bit. There would be a big difference to an arrangement with just a few exciters spaced about one foot apart. Bass performance is another story - in my opinion the requirements for panel properties for a linear high and low frequency transduction are some kind of conflicting, but this is a matter that could fill a whole new thread of it's own. Anyway - just give it some thought.

regards
-m

P.S.:

I just visited the HiWave homepage and found it interesting that the power rating specifications are not really consistent - see for youself:

taken from the HiWave homepage:


and the datasheets:
http://www.hi-wave.com/downloads/datasheets/DS-HIAX25C15-8SF.pdf
http://www.hi-wave.com/downloads/datasheets/PDS-HIAX32C20-8.pdf
http://www.hi-wave.com/downloads/datasheets/DS-HIAX32C30-4B.pdf

Generally the test methods for the automotive sector are among the strictest ones so the HIAX32C30 which was developed for this use is most likely the most robust one in the field.

Also interesting is that only the maximum mechanical excursion (peak to peak) is specified, not the linear one - so at the given excursion the distortion figures will be quite high. 

[el`Ol]

Interesting to try for somebody in the US:
http://www.taskboard.com/

[nigretti]

I think that monacor must mounted as clark tactile transducer, as you can see in clark installation manual ( http://www.clarksynthesis.com/lib/pdf/product/Transducers_InstallationGuide.pdf) Horizontally
Surely not in the way we use them till now.

[tino84]

but it could be that, maybe, clark have to be mounted horizontaly because they have to vibrate your seat or sofa, and not a dedicated structure to sound?

[nigretti]

yes but if you watch at partexpress  (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-861) they write about tactile frequency response and audiuble frequency response.

[tino84]

I don't konw if I would compare clarck with other NXT, because clarck need also to make you FEEL vibration, if I have right understand.

Generally anyway I think you're right, when possible mountin' exciters horizontally might be slighty better, if you choose to use little panel as me, but if you use large panel, you have to mount nxt vertically

[zygadr]

Good find! I did not recognize this one because it looks the same as the Dayton Audio DAEX32 Balanced Exciter 32mm which has only a power rating of 10W rms. Nevertheless i suspect its suspension system is rather stiff.

@ zygadr:

I would not underestimate those little 11mm exciters - seriously 0,5W rms is not so bad keeping the size in mind - they allow for only 25mm center to center spacing - in a line array arrangement and have 32 ohms impedance - so its possible to wire up 8 in parallel for a 4 ohm total impedance. They also seem to be "balanced" (at least the HiWave HIAX11C005-32/LP 11mm Low Profile Exciter) - this is a big plus regarding reliability and will prevent "thumbling" at higher excursions and hence reduce distortion in comparision to the not balanced ones. Imagine a 1.6m or taller panel with 64 of these exciters in series parallel wiring. This will be as close as you can get to a real continous line source with single exciters - serious side lobes will start in the range above 10khz and powerhandling will be 32W rms in total. Using the right panel properties for these little suckers (quite thin, not too stiff) could improove several high frequency problems in comparision to former designs substatially and also could boost efficiency (also due to less spl drop per distance doubling) so that the power handling capability will be less of an issue. According to my experiments with close exciter spacing it will also bring the soundstage more in front, right in your face because the nearfield is extended not only for the lower frequency range (large panel with several evenly spaced exciters), also the higher ones - remember the very good paper of Mr. James Griffin on Near Field Line Arrays posted some time ago here in this thread. Most of the principles do definitely apply for this kind of transduction althoug the close coupling of the drive units complicates the whole thing a bit. There would be a big difference to an arrangement with just a few exciters spaced about one foot apart. Bass performance is another story - in my opinion the requirements for panel properties for a linear high and low frequency transduction are some kind of conflicting, but this is a matter that could fill a whole new thread of it's own. Anyway - just give it some thought.

regards
-m

P.S.:

I just visited the HiWave homepage and found it interesting that the power rating specifications are not really consistent - see for youself:

taken from the HiWave homepage:


and the datasheets:
http://www.hi-wave.com/downloads/datasheets/DS-HIAX25C15-8SF.pdf
http://www.hi-wave.com/downloads/datasheets/PDS-HIAX32C20-8.pdf
http://www.hi-wave.com/downloads/datasheets/DS-HIAX32C30-4B.pdf

Generally the test methods for the automotive sector are among the strictest ones so the HIAX32C30 which was developed for this use is most likely the most robust one in the field.

Also interesting is that only the maximum mechanical excursion (peak to peak) is specified, not the linear one - so at the given excursion the distortion figures will be quite high. 

The DS- HIAC25C15-8SF is by far the one and only exciter to use on our panels.
Why?, it has the highest ''force factor'' of all three and is EXACTLY the one used in the Podium Loudspeakers.

In the past most of us have mounted our small weak exciters ''freely'' (directly to the rear of the panel without support). This is WRONG!
Reason being :
1. voice coil droop (guarenteed)
2. added mass to the panel
3. added mass means less output from the panel (less efficiency)

The way I see it is that we MUST mount the above exciter (no choice anyway due to its very heavy weight)to a back spline or supporting brace and then attach the panel to the array of exciter feet.
This way there will be no added mass to the panel and the exciter's voice coil will not be under strain providing the panel is supported in a frame of some sort.