TBrennan Posted February 25, 2002 Share Posted February 25, 2002 Here are my dual 4648s, flat to 25hz. I tried telling you guys about these things back in December, I guess only Ken listened. Several of my friends bought pairs of these. Quote Link to comment Share on other sites More sharing options...
kenratboy Posted February 25, 2002 Share Posted February 25, 2002 You bas*ard, you got TWO!!! One guy on the audioheritage forum got EIGHT of them!!! One is enough for me- Quote Link to comment Share on other sites More sharing options...
T2K Posted February 26, 2002 Share Posted February 26, 2002 TBrennan,what are you feeding the JBL's with? Ken's plate amp may be OK but what would a bridged Crown/Sampson do for them(YOOC)? Keith Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 26, 2002 Author Share Posted February 26, 2002 Keith---I'm using the Parts Express plateamp, it drives these babies very well, afterall the dual 4648s are 106db efficient. A big Crown running mono would get them louder, 1000 watts into a pair should give about 136 db, -3db for compression and you have 133db. But for flat response at 25 you need 6db EQ at 30 hz so subtract another 6db from that for 127db. At 25hz. Formidable performance. Quote Link to comment Share on other sites More sharing options...
T2K Posted February 26, 2002 Share Posted February 26, 2002 Thanks for the reply TB.I remember your post.Wish I had room for one(or two).Lots of return for the investment it seems.Wonder how well they would work with the LaScala? Keith Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 26, 2002 Author Share Posted February 26, 2002 Keith--A pair of 4648s would be near ideal for use with LaScalas. They have the efficiency and output to keepup with LSs plus their very low distortion will blend well with the low distortion of the LSs. My VOTs are horn-loaded from 100hz up and the JBLs work perfectly with them. Multiple large, high-efficiency drivers like this are the only way to hope to approach basshorn performance. Quote Link to comment Share on other sites More sharing options...
T2K Posted February 26, 2002 Share Posted February 26, 2002 Thanks TB. Keith Quote Link to comment Share on other sites More sharing options...
J M O N Posted March 12, 2002 Share Posted March 12, 2002 Tom: I was very tempted to order the 4648 when you recommended them back in December, but wasn't able to for several reasons. Now that the 4648's are gone, and only the 4638's are left (assuming they haven't sold out yet), I'm still thinking about these. Aside from being 4 ohm, do you know if the 4638's are comparable to the 4648's? Quote Link to comment Share on other sites More sharing options...
TheEAR Posted March 12, 2002 Share Posted March 12, 2002 TBrennan, Nice little subs you have. Four 15" drivers should do the trick,even with your VOT I have little doubt these brutes can keep up.At 106dB for ONE WATT input these dont need too many watts to spank. I was looking at the twin 18" JBL units,I like the idea of massive cone surfaces moving very little.Distortion is low and the bass speed improves. Did you see the new JBL Ti-K sub? It performs alot like JBL PRO subs in a smaller package.I have no space to fit fridge sized boxes,if I had space I would not hesitate a minute. TheEAR(s) Now theears Quote Link to comment Share on other sites More sharing options...
TBrennan Posted March 12, 2002 Author Share Posted March 12, 2002 Ear---You get it mon ami, big area and little movement sounds best, that's why horns sound good. And using lots of cone area like I do is the only way to match the "speed", dynamics and low distortion of horns. That's actually 6-15" drivers there Ear, the 515s in the VOTs are running as low as they can too though they are about 12 db down at the 25hz where the JBLs are flat, but they're helping. The VOTs have a shelved response below 100hz where the horn part of the woofer enclosure "hands-off" to the reflex part. JMON--I think the 4638s should perform about as well as the 4648s, the drivers are of very high quality and the 4638 specs about the same as the 4648, they should certainly be low distortion devices. I'd get'em. This message has been edited by TBrennan on 03-12-2002 at 08:51 PM Quote Link to comment Share on other sites More sharing options...
kenratboy Posted March 12, 2002 Share Posted March 12, 2002 I THINK the 4648 and 4638 should preform about the same unless you pour 1000 watts into it for 8 hours a day! ------------------ Receiver: Sony STR-DE675 CD player: Sony CDP-CX300 Turntable: Technics SL-J3 with Audio-Technica TR485U Speakers: JBL HLS-610 Subwoofer: JBL 4648A-8 Sub amp: Parts Express 180 watt Center/surrounds: Teac 3-way bookshelfs Yes, it sucks, but better to come. KLIPSCH soon! My computer is better than my stereo! Quote Link to comment Share on other sites More sharing options...
J M O N Posted March 16, 2002 Share Posted March 16, 2002 I was comparing the JBL specs between the 4648's and the 4638's and it appears that the 4638's might be able to go just a bit lower. The 4648 spec sheet says it has usable response to 35Hz and the lower frequency limits are -3dB at 45Hz and -10dB at 35Hz, where the 4638 spec sheet says it has usable response to 30Hz and the lower frequency limits are -3dB at 45Hz and -10dB at 30Hz. I would also guess that both models are very comparable, but for MY particular application the 4638 may actually be slightly better based on these spec sheets. Thanks again for the tip Tom, I've decided to go ahead and order the 4638. Hopefully they still have some left! Quote Link to comment Share on other sites More sharing options...
Deang Posted March 16, 2002 Share Posted March 16, 2002 but i like the sound of 2nd order harmonic distortion ------------------ dean Quote Link to comment Share on other sites More sharing options...
kenratboy Posted March 17, 2002 Share Posted March 17, 2002 Shoot, throw a reverb on the sub and get 20 seconds of 2nd harmonic distortion!!! If I was watching movies, the JBL probabely wouldn't be the PERFECT (but damn good) sub, I listen to 98% music, so little distortion is good for me. I should buy a $150 reverb and try it out! ------------------ Receiver: Sony STR-DE675 CD player: Sony CDP-CX300 Turntable: Technics SL-J3 with Audio-Technica TR485U Speakers: JBL HLS-610 Subwoofer: JBL 4648A-8 Sub amp: Parts Express 180 watt Center/surrounds: Teac 3-way bookshelfs Yes, it sucks, but better to come. KLIPSCH soon! My computer is better than my stereo! Quote Link to comment Share on other sites More sharing options...
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