Hi
Just wondering if anyone has experience (positive or otherwise) with the Revelator woofers from Scan-Speak operating in sealed enclosures, this 10” unit in particular:
http://www.madisound.com/catalog/product_info.php?cPath=45_228_258&products_id=1664
WinISD reveals a ~40Hz f3 in a relatively modest size enclosure.
Worth the money?
Cheers,
Glen
Just wondering if anyone has experience (positive or otherwise) with the Revelator woofers from Scan-Speak operating in sealed enclosures, this 10” unit in particular:
http://www.madisound.com/catalog/product_info.php?cPath=45_228_258&products_id=1664
WinISD reveals a ~40Hz f3 in a relatively modest size enclosure.
Worth the money?
Cheers,
Glen
I can't answer your question Glen, but look at SPL in relation to voice coil impedance also maximum air displacement capability.
http://www.madisound.com/catalog/product_info.php?manufacturers_id=127&products_id=1768
Oh, just gone out of stock, but comparisons still possible. Was $91.
You pay much for little displacement with the ScanSpeak and this is what counts by the time you get to say 25Hz.
Just one of these will move as much air at LF as 2.5x ScanSpeak -
http://www.eminence.com/proaudio_sp...ink=DeltaPro-18A&speaker_size=18&SUB_CAT_ID=1
but then of course the nature of the cabinet/mounting might be different to your requirements.
Cheers ........ Graham.
http://www.madisound.com/catalog/product_info.php?manufacturers_id=127&products_id=1768
Oh, just gone out of stock, but comparisons still possible. Was $91.
You pay much for little displacement with the ScanSpeak and this is what counts by the time you get to say 25Hz.
Just one of these will move as much air at LF as 2.5x ScanSpeak -
http://www.eminence.com/proaudio_sp...ink=DeltaPro-18A&speaker_size=18&SUB_CAT_ID=1
but then of course the nature of the cabinet/mounting might be different to your requirements.
Cheers ........ Graham.
Not the same woofer but I did try the 22W8851T00 (paper cone) in 2 different applications and both times were bettered by a Vifa M22WR-09-08. Could just be a case of wrong driver, wrong application but it should have worked better as it did model very well.
I'm a great fan of Scan Speaks such as the 18W8531G00 but I found the 8" not very good value. The 10" however could be a different story.
A 10" driver which is great value and I've had a lot of customers who loved it is the Vifa M26WR-09-08 but now are very rare and last time I checked, WES were down to their last few.
Good luck with your research.
I'm a great fan of Scan Speaks such as the 18W8531G00 but I found the 8" not very good value. The 10" however could be a different story.
A 10" driver which is great value and I've had a lot of customers who loved it is the Vifa M26WR-09-08 but now are very rare and last time I checked, WES were down to their last few.
Good luck with your research.
Hi Glen,
Don't know if you have seen this before, but is worth reading; illustrates different 'Q' responses etc.
http://www.geocities.com/cc00541/group_delay.html
Cheers .... Graham.
Don't know if you have seen this before, but is worth reading; illustrates different 'Q' responses etc.
http://www.geocities.com/cc00541/group_delay.html
Cheers .... Graham.
Graham Maynard said:
OK, thanks Graham.
18” is a bit big and Eminence sub will only really work in a ported enclosure (it will only do ~80Hz sealed).
I think David Gatti summarises the case for sealed bass enclosures well here:
http://www.gattiweb.com/delta_design.html
I also really like the look of this Sonus Faber speaker:
An externally hosted image should be here but it was not working when we last tested it.
Hmmm....perhaps a 3-way version, except with a stained pine baffle and a gloss black enclosure, with a pair of bass drivers in parallel for high sealed box sensitivity.
With the drivers that are available that work well in sealed boxes, it looks like I will have to settle for an f3 of about 40Hz.
Fortunately I have nearly all the parts, including the heatsink and 25 pairs of genuine Motorola MJ15024/MJ15025 which I bought years ago, with which I could whack up an easy beast of a subwoofer amp, perhaps to drive an Exodus Audio Maelstrom or a Shiva-X.
With an actively x-o’ed subwoofer/amp I could then I could have my 4-way system
I think this will be a good all over compromise, rather than trying to achieve everything in a single pair of speakers.
Cheers,
Glen
Attachments
I've used a pair of those 10" Aluminum cone Revelators in a 3-way tower, but I ran them vented. They performed extremely well I thought. Vented they dig deep, stay composed at very high SPL, and integrated well with the top - more musical I thought than a Seas L26 or Dayton RS270, and more impact than a W26 Mag cone. But they're still overall a dry bass presentation, if you want more warmth there's a paper cone 10" Revelator too. One of my favorite 10's for 3-way use is a Focal 10W, if you can find them, but it doesn't like small boxes. A Hi-Vi D10.8 also is a nice driver, and performs well in a sealed 2.5cu/ft box.
G.Kleinschmidt said:
The eminence is a 15" and its actually best sealed (6 cu ft +) and used as a room corner loaded sub for freq.s less than 40 Hz.
The case for "sealed" bass really doesn't "measure up" in a well designed system. Group delay is important - for fundamentals. IF you have a low enough port resonance then this is often a moot point. The same is pretty much true for excursion potential - its really a matter of low freq. content at or near the spl average. If you have a fundamental (or a loud grouping of harmonics) just below the port resonance then you can greatly increase driver excursion beyond what a normal sealed system would provide. However if that isn't the case then often a bass reflex design has LESS excursion (and lower non-linear distortion). Furthermore the driver is much better controlled near its in-box resonance (which is often within the range of fundamentals) *because* of its port. Finally a low freq. tunning point (less than 30 Hz) in a bass reflex design that is *not* "aligned" can actually match room-gain better than a sealed design.
None of the above though isn't to suggest that a sealed system isn't also good, rather that its all down to the design.
If you like the enclosure for the Stradivari then you should look at Troel's site:
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
specifically:
http://www.troelsgravesen.dk/Acapella_WB.htm
http://www.troelsgravesen.dk/PMS.htm
http://www.troelsgravesen.dk/PMS-EXCEL.htm
Personally if I was going for a 2 driver sealed design I'd use 2 10" Eminence BP102's in 80-100 lt enclosure. Wired in parallel (with a suitable amplifier) provides a 40Hz figure of around 90 db 1 watt 1 meter *without* taking into consideration either room OR boundary gain.
As mentioned, I use the Scanspeak 26W8861 in my Delta speaker and love it! Its very fast, goes very deep and stays clean. Its parameters seem perfect for moderately sized sealed enclosures. The aluminium version you mentioned with the 4 ohm impedance looks great too, if it meets your needs, but keep in mind these are not subwoofers and cant compete with the likes of Adire. Their strength is in their speed and neutrality beyond 500 Hz which you couldnt reach with 99% of subwoofers,
Some have mentioned the advantages of the bass reflex enclosures and I dont dispute them. The sealed boxes are generally smaller though, hence more rigid, and will also allow you to completely stuff them to avoid internal standing waves, important if you're using it in the 500Hz range.
Some have mentioned the advantages of the bass reflex enclosures and I dont dispute them. The sealed boxes are generally smaller though, hence more rigid, and will also allow you to completely stuff them to avoid internal standing waves, important if you're using it in the 500Hz range.
G.Kleinschmidt said:
It didn't have the extension and drive of the M22WR. When you pay that much for drivers even at the prices I get them for, you want them to work and try hard to get them going. By the specs I expected better performance.
Designing boxes for bass production is not rocket science, very easy in fact and I just couldn't get them to perform to my satisfaction. They were partnered with some 18W8531G00 in OB so it was going to be an all Scan Speak speaker.
ScottG said:
Thanks for those excellent links! A lot to chew on here WRT vented Vs sealed bass enclosures. Vance Dickason seems to come out in favour of sealed enclosures in his Cookbook and the sealed bass performance of speakers such as the NHT-3.3 has persuaded me to some degree.
A sealed enclosure is currently somewhat more appealing to me from a design POV, being a beginner.
However if the case for sealed enclosures doesn’t really stack up in the end then I guess I could change my mind.
With regards to the EMI-1550 15” subwoofer, when I plug the T/S parameters into UniBox or WinISD for a Vbox computation for Qtc of 0.7, I get Vb of 52L with f3 of 80Hz. I can make the box bigger and get a lower Qtc, but not a lower f3. How can that make a <40Hz sealed subwoofer? Am I missing something here?
TurboFC3S said:
Ok, cool, I'll look up the specs for those other drivers. How large was the internal volume of your bass enclosure and how low did it go?
Cheers,
Glen
Without serious engineering know how I find a 3-way hard to design. And a serious waste of money if dropping big bucks on drive units.
I've got a pair of the M22WR and M26WR and they are great woofers. Nice sensitivity in normal sized boxes. Soundwise it's got a nice punch and rich sound, but ultimately the limited x-max reduces maximum SPL capabilty.
However, sometimes whether it a driver sounds good or not good is highly dependant on my (shooting in the dark) design. If you're like me just fiddling with calculator crossovers, tuning by ear and without a complete suite of measurement equipment, I find it a bit of a hit or miss. For instance, it might just sound better because for some reason woofer A is playing 1dB louder than woofer B, and you know.. one sounds thin and medicore and the other sounds rich and powerful.
I've got a pair of the M22WR and M26WR and they are great woofers. Nice sensitivity in normal sized boxes. Soundwise it's got a nice punch and rich sound, but ultimately the limited x-max reduces maximum SPL capabilty.
However, sometimes whether it a driver sounds good or not good is highly dependant on my (shooting in the dark) design. If you're like me just fiddling with calculator crossovers, tuning by ear and without a complete suite of measurement equipment, I find it a bit of a hit or miss. For instance, it might just sound better because for some reason woofer A is playing 1dB louder than woofer B, and you know.. one sounds thin and medicore and the other sounds rich and powerful.
Hi Glen,
No, you are not missing something.
Larger high VAS drivers need larger enclosures to go low. Though if driven by a separate LF amplifier with EQ which matches their enclosured characteristics, then they can provide much increased LF SPL for an equally sized cabinet, and, more cheaply.
It comes down to David's neutrality comment, your design, and where you wish to have crossover frequencies (which is not for me to say, and indeed I would not want to).
Cheers .......... Graham.
No, you are not missing something.
Larger high VAS drivers need larger enclosures to go low. Though if driven by a separate LF amplifier with EQ which matches their enclosured characteristics, then they can provide much increased LF SPL for an equally sized cabinet, and, more cheaply.
It comes down to David's neutrality comment, your design, and where you wish to have crossover frequencies (which is not for me to say, and indeed I would not want to).
Cheers .......... Graham.
G.Kleinschmidt said:
Most of the problems you are having with various designs seem to be revolving around targeting for an *anechoic* & *acoustic* flat summed response (IB) to some pre-determined low freq..
What you need to be thinking about is the specific passband you desire AND its linearity IN-ROOM.
For instance IF you look to the EMI 15" driver as a device operating BELOW 40 Hz.. then do NOT *yet* worry about the freq.s above 40 Hz. Instead look to the behavior BELOW 40 Hz and how that might interact in a room. Excepting some problem modes (of which their are few when driven below 40 Hz), the room itself (depending on size, shape, and, construction) will have some *progressive* gain as freq.s decrease, which might well count for 4-6 db between 20 Hz and 40 Hz. Then tack-on another +9 db via the room corner loading. Then make another sub and put it in another room corner and wire it in parallel for another +6 db. With a 6 cu. ft. enclosure the anechoic response at 20 Hz is around 79-80 db. THEN add-up the additional gains (..though its a bit less depending on how tightly acoustically coupled the driver is with the room's corner - stemming from any baffle-loss). THEN go back and look at the rest of the lower freq. response (below 20 Hz) which extends very deeply for its sp-levels (..understanding that generally room-gain continues as freq.s lower). After doing all that only then do you really concern yourself with its freq. response linearity and its low-pass filter and summation with a pair of loudspeakers.
As perhaps a more pertinent ex. consider the paralleled Eminence BP102 suggestion I made earlier. As I mentioned previously with the parallel config. the low freq. response was about 90 db at 40 Hz with 1 watt at 1 meter in an 80-100 liter *sealed* enclosure with an infinite baffle. Of course this means that at 100 Hz its around 98 db at 1 watt at 1 meter (IB). That additional gain will need to be padded down if you want a flat-summed anechoic response. Realistically though you need to look at how the drivers interact with each other and the baffle, the floor boundary, room gain, floor bounce, etc.. I can virtually guarantee you that a flat summed anechoic response will not result in a flat response (and this is irrespective of modal issues). The *key* though is that you have plenty of gain to work with. Realistically (with a 90 db mid and a large baffle like the Stradivari) you could probably achieve something relatively flat down to BELOW 30 Hz with still plenty of sp-levels as freq.s decrease further.
Again, its the "total" design that counts, not simply a preconceived targeted response.
G.Kleinschmidt said:
One old and simple rule of thumb that does a reasonable job of telling you whether you shold be barking up a sealed tree or a vented one is the so-called Efficiency-Bandwidth Product (EBP) which is Fs/Qes. If that ratio is less than 50 it points to a sealed enclosure. If it's greater than 100 it points to a vented one. 50-100 are fence-sitters. For the EMI driver that ratio is 105, so I am not surprised if you don't seem to be getting acceptable results with a sealed box for this driver.
-Ram
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