CharlieTuna Posted February 24, 2002 Author Share Posted February 24, 2002 Anyone, Correct where I'm wrong: Adding an addtional 15" woofer will not produce a deeper (lower frequency) sound, but will produce more sound. You will be generating the same sounds waves with two sources instead of one, producing more sound waves. Maybe what's happening is (ideally) you are geting constructive interference with the waves from the two sources (cabinet/speaker design), which increases the wave's amplitude (power or volume) in decibels. The wave's frequency does not changes. The ability to line up the waves such that wave peaks match is called making the sources "in phase". Out of phase sources can cause wave cancellation or "destructive interference" and adversely affect your sound quality. But hey, I graduated from college a long time ago. Physics has not changed, but I have. CT ------------------ ===================================== You can tune a radio, but you can't tuna fish! ===================================== Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 24, 2002 Share Posted February 24, 2002 Charlie---Correct, adding another driver increases efficiency and peak output and lowers distortion but in and of itself does not give lower bass. Quote Link to comment Share on other sites More sharing options...
CarlV Posted February 25, 2002 Share Posted February 25, 2002 Guys, I ordered the 4638 last week and should be receiving it today or tomorrow. I'm pairing it with my SVS 16-46, I think this will be a match made in heaven They will be powered by a Denon POA 5200 amp - about 200 watts into 4 ohms. I will give a review once I have tested the sub. You just can't beat $216. Carl Quote Link to comment Share on other sites More sharing options...
kenratboy Posted February 25, 2002 Share Posted February 25, 2002 CONGRADULATIONS CarlV: Look at the "WORST subwoofer out there" thread to see more info about the 4638, another person just got order conformation and I have its bigger brother. Thats three JBL Tent Sale people I know of so far. What power amp are you using? Two of us are using the Parts Express power amp. Quote Link to comment Share on other sites More sharing options...
kenratboy Posted February 25, 2002 Share Posted February 25, 2002 Opps! Disreguard that last question, I didn't read the Denon part. What is that Denon amp? Is it a receiver or a power amp? Quote Link to comment Share on other sites More sharing options...
CarlV Posted February 25, 2002 Share Posted February 25, 2002 It's a 2 channel power amp with discrete power supplies to each amp. I have it connected to my newly aquired Denon 4800 receiver. Hopefully it will be enough to power this monster. Quote Link to comment Share on other sites More sharing options...
kenratboy Posted February 25, 2002 Share Posted February 25, 2002 Hey CarlV, your from Vegas, I'm from Reno. Thats as good as being from different states, though!!! I think a solid 25-50 watts would be enough to make the subwoofer explode, so I wouldn't sweat it. My $130 Parts Express amp with 180 watts is overkill to the extreme. If your Denon cannot drive the sub, which I doubt, get a more powerful amp, not a huge problem. Quote Link to comment Share on other sites More sharing options...
boa12 Posted February 25, 2002 Share Posted February 25, 2002 krb, i posted in the other thread but when u said u tried a few receivers & they didn't move it that concerned me. take it though those receivers didn't meet the good 35-40 watts criteria? ------------------ My Home Systems Page Quote Link to comment Share on other sites More sharing options...
kenratboy Posted February 25, 2002 Share Posted February 25, 2002 Like I said, they were cheap junk amps, like toys. The "real" reciever (the one that came with the big-screen 10 years ago) consumes 150 watts from the wall and says it can put out 100 watts X 2 channels. My $130 Parts Express sub amp puts out 180 watts, but takes 450 watts from the wall. I bet the old reciever (big-screen one) has about as much power as a mini-bookshelf system, for real. The other amp I used with the subwoofer was an old Aiwa bookshelf system, but I don't think it liked the load, It came with 6 ohm speakers, but its finity with 8 ohms and it will not tolerate 4 ohms (I wrote that correctly, it doesn't like 8 or 16 ohms) I think any half-decent piece of equiptment will be fine, Denon, Harman kardon, or better. Quote Link to comment Share on other sites More sharing options...
boa12 Posted February 25, 2002 Share Posted February 25, 2002 thanks again krb. this ole ken is a monster dual power supply, mosfets & huge capacitors. hmmm, i'll keep thinkin on it. ------------------ My Home Systems Page Quote Link to comment Share on other sites More sharing options...
jnorv Posted February 25, 2002 Share Posted February 25, 2002 Does anyone know if the woofers in these JBL monster have their own rear volume or is the cabinet just one big box? I ordered mine yesterday. I figured that the parts are worth the money. I think my Bryston 4B in bridged mono may just be the ticket. Jim Norvell Quote Link to comment Share on other sites More sharing options...
jnorv Posted February 25, 2002 Share Posted February 25, 2002 Does anyone know if the woofers in these JBL monsters have their own rear volume or is the cabinet just one big box? I ordered mine yesterday. I figured that the parts are worth the money. I think my Bryston 4B in bridged mono may just be the ticket. Jim Norvell Quote Link to comment Share on other sites More sharing options...
kenratboy Posted February 25, 2002 Share Posted February 25, 2002 No, the enclosure is all open inside, except for about 15' of 2X4's. You will all be shocked by the cable inside. What sort of cable do you imagine would be inside? 14, 12, maybe even 10 gague. Well, its closer to 18 gague! The stuff, with insulation, it about as thick as a piece of spagetti! It does the job, though. Also, the binding posts are really wierd, they will (on mine) ONLY accept connectors like pins, there is an 1/8" hole the cable goes into, so no banana plugs. Quote Link to comment Share on other sites More sharing options...
J M O N Posted March 15, 2002 Share Posted March 15, 2002 quote: Originally posted by TBrennan: ...in fact the lack of distortion makes them sound less "impressive" than home subs that make huge amounts of 2nd harmonic distortion or "doubling". They don't rumble like most home subs; they hit hard, shake the house and then quiet down until the next hit. Very clean and very "transient". That's exactly what I am looking for. Thanks for the info! Quote Link to comment Share on other sites More sharing options...
kenratboy Posted March 15, 2002 Share Posted March 15, 2002 The lack of distortion is great for music. Like I have said, the 15" woofers hit QUICKER than my 6.5" bookshelf speakers!!! ------------------ 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...
Audible Nectar Posted March 15, 2002 Share Posted March 15, 2002 OK, I took the plunge and purchased a pair of JBL 4638 woofer cabinets. Four 15" JBL pro woofers should keep up with the Cornwalls (hehe). I made the mistake of "under purchasing" a bit on my current sub, so I figure if I overpurchase now, it will be just right Can't say no for the $433.20! I should have my 15" Velodyne for sale soon... Now, some questions: I gather from the discussion that each bin (2 woofers) uses one channel of amplification, and the amp sees a four ohm load. Rather than buying two plate amps, could I just buy a 2 channel used amp? If I do this, what options are available for a continously adjustable crossover (not necessary for HT, but I like one for 2 channel music use). I really don't want to buy 2 plate amps (and find a place to put them) - I can handle another amp in my rack. Good used 2 channel amps are cheap enough if I can find a good crossover unit for the woofers. So what is my best option for 2 channels of good amp with the proper subwoofer controls?? Any recommendations on an electronic crossover unit for sub use that won't break the bank? ------------------ First we Rock, then we Roll! Quote Link to comment Share on other sites More sharing options...
J M O N Posted March 16, 2002 Share Posted March 16, 2002 quote: Originally posted by dndphishin: ...Rather than buying two plate amps, could I just buy a 2 channel used amp? Yes, that is actually what I am planning on doing as well. When your speakers have a lower impedance (4 ohm), that requires the amp to be capable of putting out more current. The closer the impedence gets to zero, the closer it becomes to becoming a short circuit. 4 ohms shouldn't be a problem for most amps though (just don't get something cheapo), that is what is most common in car speakers. Quote Link to comment Share on other sites More sharing options...
Audible Nectar Posted March 16, 2002 Share Posted March 16, 2002 Jmon: The loss with buying the 2 channel amps, however, is the loss of the sub controls. I figure I can buy a used, relatively high end amp of good quality - stable below 4 ohms - quite easily. I guess I need a separate crossover, and the 30 hz eq adjustment TBrennan mentioned would be nice too. Is this type of unit an option as a component? Do these Samson type amps have such controls built in? ------------------ First we Rock, then we Roll! This message has been edited by dndphishin on 03-16-2002 at 12:28 AM Quote Link to comment Share on other sites More sharing options...
Maximo Posted March 16, 2002 Share Posted March 16, 2002 Paradigm makes a sub crossover unit, I think its about $150, and has the basic Hz and phase controls I believe. I bought a parasound HCA1000A and it has warning lights for overload. I have it bridged mono and the lights havent came on yet so , so far so good. Quote Link to comment Share on other sites More sharing options...
TheEAR Posted March 16, 2002 Share Posted March 16, 2002 Maximo, Yes Paradigm does make the X30 crossover,works great with subs that use outboard amps.I have two X30 crossover units(one with Sunfire subs and one with the three Klipsch on my PC sound system). Great buy TheEAR(s) Now theears Quote Link to comment Share on other sites More sharing options...
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