Steve, here is Jo Fo's front speakers, as you can see his centre something his subs are not in the picture. http://www.jonathanfoulkes.com/images/Animation%20FullFrontViewFlipBook.gif Cheers George |
That will make quite a difference. Best to lay the Monolith on it's back take the driver out and stuffing, fill with bean bag styro bean fill, empty all into a known litre/gallons container (I use a 20lt contaner I had) to get the exact volume. Then Google litre/gallon to cubic ft and use the calculator to find the exact cubic ft on the Monoliths bass enclosure size include bracing, esl power supply, wires ect. Cheers George |
Sorry Tim but you clearly have no experience with mating esl’s which are very fast (low mass) compared to a dynamic drivers (much higher mass), as there are big problems at the xover point to get them to seamlessly sound coherent and it is an art to get them to do so. A low FS for LF, and a low MMS for speed at the xover point is a good place to just to start, this is why the SV12 is an ideal choice. Adding mass to a driver just to get it to go down further will create problems up higher exacerbating the problem where this xover point is most critical to have both esl and driver sounding/blending well to be coherent. Over here a Monolith I (ported) sounds worse in the (above area) and is reflected in it’s used value around $3k. A Monolith III (sealed) used fetches between $10k-$12K why would anyone want to port this and "maybe" get a worse sound. BTW: Bean bag (pellet) fill (beans being the operative word) will give you an exact volume measurement of that weird shaped enclosure, as it takes everything inside the enclosure into account. I hope your not thinking, leaving the fill in there as stuffing??? As that would be stupid. It’s a precise measuring tool, then to be taken out and put into a symmetrical container to work out the correct volume of the Monoliths weird shape enclosure volume. Cheers George |
If you do raise the xover point to 300hz you get the problem that many speakers have of having two drivers doing the critical midrange. This is even much more accentuated with ESL’s. This is why a Monolith with a 150hz xover sounds so much better in the critical midrange than a ML Summit with a 300hz xover. The reason Jon Fo went this way is because he uses 4 x Monoliths with external subs is for HT use with all that processing and that critical midrange xover in HT is not as big a problem than just hi-end stereo use. Cheers George |
I have many time added mass to raise qts so that a woofer would go down better in sealed box.Adding mass to the cone does lower the FS, but you didn't mention it also raises the distortion (slows down it's reaction time) at the higher end of the woofers capabilities. You give to one end but take away from the other, there's no free lunch. Because it's such an odd trapezoidal type of shape, I'm positive when I bean bagged filled the bass chamber to do a proper volume check, it was more than 2.5cu ft. Cheers George |
stevepaJust listen to the Eminence ones till you get some SV-12's, two of us, Jon Fo and I both looked for a replacement for a very long time and the SV-12 was the one. Jon Fo later did raise the xover point to some 300hz? to take away some of the power frequencies from the ML esl, and then used the Peerless 830699 for bass/mid/upper bass but I think he then used big external subwoofers as well to make up for the Peerless no being able to go down. Cheers George |
I don’t like over stuffing a box, (unless your box is too large) it actually raises QTC by limiting air flow, the woofer acts as though it is in a smaller cavity.Neville Thiel rip, said the opposite to me, it increases the apparent box size as seen by the woofer and lowers the Q. Gale GS401 and Infinity 4.5’s were a classic cases of one of the fastest/tightest detailed bass at the time, heavily stuffed, the drivers had to be pushed down while tightening the mounting screws, sure they were probably a bit harder to drive. Cheers George |
just ran curves on the SV12 in 3 cu ft sealed.... It'll be 3db down @ about 31 hz with a qtc of .79I can't be sure about the 3cu ft as I didn't save it, I think with a heavily stuffed ML box that came down to around 20-25hz and around .6 which was I was told by Neville Thiel (rip). Sliightly less efficient, but that was fine as it was active xovered. Cheers George |
you must vent or port your box with this wooferThe Monolith I was ported and the bass couldn’t keep up with the speed of the esl, that why with the II and the III they went sealed, tighter faster except they used that junk cheap driver, I posted it’s T/S here. http://www.martinloganowners.com/forum/attachment.php?attachmentid=18105&stc=1&d=1437711906 The one Jon Fo used could work Peerless 830699 but it’s FS is much higher (double) that of the SV-12 http://www.martinloganowners.com/forum/showthread.php?16441-ML-Monolith-III-and-damaged-woofer&p=173694&viewfull=1#post173694 Cheers George |
SLS 830669FR too high for me. I was told by a mate here in Australia who also wanted them for his Monoliths after he heard mine, that this guy still had the SV12's but he wouldn't ship to Australia. http://www.highdefjunkies.com/showthread.php?t=14425&s=2374d39826a05548a2cfbdafd2d0c666&p=35... Cheers George |
This guy had a pair for sale that no one picked up on, just "maybe" he still has
them. http://www.highdefjunkies.com/showthread.php?t=14425&s=2374d39826a05548a2cfbdafd2d0c666&p=354307&viewfull=1#post354307 Cheers George |
They were too expensive to make that’s why they were stopped, but many were sold, dig deep for used ones. The SV-12 were only one I found that went low enough and up 130hz, also known as the Meniscus SW1284. There were some that had as good LF performance but they weren’t to good up at 130hz, meaning they had to be cut off lower at 100hz and the ESL isn;t good down that far. Here are the T/S specs which ended being perfect for the Monoliths sealed enclosure. Especially if you used the SV-12 Third Order Sealed System which is just a 2500uf non-polarised cap in series with the + line, takes the +2db bump out before it rolls off at 25hz and takes it a little lower to 20hz, very tight and flat and protected against amps going dc. ACI SV-12 T/S Nominal Diameter: 12", . Impedance: 4 ohms, . Range: 15-500Hz . RMS Power: 350 watts, . System Power: 500 watts, . Sensitivity: 90 db · Magnet mass: 1930 grams, . BL: 8.9 Tm, . Fs: 17.5 Hz · Qms: 8.35, . Qes: .41, . Qts: .395 · Vas: 250 liters, . Cms: 1041.67, . Mms: 99 grams, . Mmd: 93 grams · Xmax (linear one way): 12.87 mm, . Voice Coil Diameter: 2" · Sd: .0460m2 · Voice Coil Height: 31.75 mm, . Air Gap Height: 9.652 mm · Voice Coil Inductance: 1.45 mh, . Voice Coil Resistance: 2.97 ohms · 12 3/8" overall width, . hole size 11 1/8" Flange depth 3/8" (1/2" with gasket) · Overall depth from front of flange to rear of magnets: 6" · Driver displacement: 2 liters, (130 cu.in.) · Heavy duty, gold-plated, high-pressure solder less terminals http://cdn.avsforum.com/f/ff/ff5db2a3_vbattach139511.jpeg http://www.madisound.com/store/manuals/SV12Specs.pdf Cheers George |
Yes, the driver ML commissioned Eminence to make is rubbish compared to the rest of the speaker, it has a one note bass, I’ve got all the T/S parameters on it, not good. The ACI-SV12 ( Meniscus SW1284 ) I matched and replaced them with are miles better, for that box. You’ve got to find a used pair though. I could find much else that suited. Heavily stuff the box so you get a lower Q (.6) to equal the speed of the esl panels, cross the SV-12’s over with 24db active at 130hz, Keep using the ML’s own passive 18db xover to the ESL though, as it sound better than active. You’ll then have a speaker that comes close to the ML Neoliths. Cheers George |
