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#1
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Sub Amps - a Follow up Question
OK, I have been looking into an amp to go between my (new to me) passive sub and my (6 mo old) A/V Receiver. The Receiver has a single SUB output jack, but the speaker enclosure has both L & R inputs, in fact it has outputs as well for I assume satellite speakers if I so choose. (We'll ignore those.) My plan is to add this sub to an existing setup that already had decent Front, Center and Surround speakers. My question this time around is how best to deal with a single Sub Output from the source through an Amp and on to a Stereo (perhaps dual voice coiled?) Subwoofer. Here's what I've brainstormed already: - Run just one channel of the Amp and the Sub, ignoring the other winding in the speaker & the other channel of the amp. - Find an Amp that will accept a single input and will in turn output to stereo. - Same as option #1, but use both speaker windings, basically changing the Ohms rating. - Find a Mono Amp and A) Use just one winding in the speaker, or of course B) Single in, Single out but use both windings on the Sub. What say ye? TBerk |
#2
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OK, I have been looking into an amp to go between my (new to me)
passive sub and my (6 mo old) A/V Receiver. The Receiver has a single SUB output jack, but the speaker enclosure has both L & R inputs, in fact it has outputs as well for I assume satellite speakers if I so choose. (We'll ignore those.) _________________________________________________ The Reciever has an RCA connection marked sub out, correct? If so just connect the RCA cables from there to the sub input which I assume are also RCA connectors. Just to be sure, we are talking about a powered subwoofer, correct? The sub out from the reciever should already sum the LF to mono so no need to worry further. The only other setups I've seen are when the connections on the sub woofer are for speaker wire input from the amp/reciever and outputs to the main front speakers. ________________________________________________ My plan is to add this sub to an existing setup that already had decent Front, Center and Surround speakers. My question this time around is how best to deal with a single Sub Output from the source through an Amp and on to a Stereo (perhaps dual voice coiled?) Subwoofer. __________________________________________________ ____ Just connect form the sub output on the reciever, to the input on the sub. then you go about setting up the crossover on the sub to blend with the main front speakers. It would be best (if you haven't already purchased the sub) to get a sub that has both adjustable high and low pass filter sections, failing that a passive sub with a separate amp that has, (as many proamps do) a low pass filter and then add a high pass filter. The reason for this, is to limit the LF output from the main speakers and save them from working in their most difficult area. Not having paid any attention to what the abilities are of an A/V reciever I can't say if these sort of features are already built in, but I'm sure the owners manual will tell you. __________________________________________________ ____ If you buy a passive sub, or build one then you need an amp that can be bridged to mono and preferably you need both high pass and low pass functions to send only frequencies below a certain point (80Hz or less, although the sub out will likely be 150-200 Hz) and send only frequencies above a variable point to the main speakers. They need to be variable and preferably the slopes should be 24 dB/octave to keep the bass in the sub and not leak out. www.hypex.nl has some of the best sub amps around. Do a search for pro amplifiers and you will find there are many affordable choices for bridgeable amps that will provide you with ample power at lower prices than the typical sub amp. Then if you want to be thourough, add a parametric EQ to smooth out probable FR bumps imposed by the room. Adire's Shiva and Tempest drivers are some of the best subwoofer drivers available, and plans for cabinets are easy enough to find through them as well. Another option in the DIY sub area is Rhythmik Audio which also have a very godd product. If yo go the DIY route look into the possiblity of using sonotube instead of an MDF cabinet. You might wind up with a sub that looks something like a water heater, but it will be at least as strong as a conventional cabinet and much cheaper. Adire also makes finished subs. Other good subs that are already assembled are, HSU, PSB, NHT (who also sell there 12" woofer to the DIY market for use in a sealed enclosure, the absolute easiest DIY project there is), and SVS. All of these are good products and will give you excellent bass. Lastly you will need something that generates test tones so you can match the sub to the mains, and an SPL meter to measure the levels so you can match them for smooth integration. You might want to check with the subwoofer section of www.diyaudio.com and check the archives for some of the projects that have been done by the participants. There are plenty of online resources if you go the DIY route, which is what I did. I'll never buy a ready made sub again, since I know you can get equal or better performance by doing it yourself. |
#3
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In , on 04/10/05
at 11:08 AM, T said: [ ... ] The Receiver has a single SUB output jack [ ... ] The RCA subwoofer output jack on a surround sound receiver is MONO and any frequencies that don't belong to the subwoofer have been removed. In the setup menu for the receiver, claim that the front and/or rear speakers are "small" if you want bass that normally would be routed to them to be withheld and routed to the subwoofer instead. Assuming you have an appropriate amount of power and a capable subwoofer, it doesn't matter if you use an external amplifier or an amplifier built into the subwoofer. The subwoofer is MONO even if it has a left and a right input. Connecting to only the left or right input decreases the output level a bit, but you can easily compensate for that by turning up the level adjustment. (You will have to adjust the level anyway so that the subwoofer output matches the main channels.) A dual coil passive subwoofer appears as if it is two speakers. If you use both coils, your amplifier will behave as if a second speaker has been added. (Depending on who is lurking on the news group, this statement may create some "flames". If it does, draw your own conclusions after the flames have died down a bit.) Passive subwoofers don't usually include level controls. Hopefully, the gain of the external amplifier is variable or compatible with the subwoofer output adjustment range of your receiver and the subwoofer efficiency. It's a complex discussion when debating if the power handling capability of the subwoofer would be much different when driving one or both coils. True, the impedance seen by the amplifier is different, but all the heat from the subwoofer coils is being dumped into the same confined space in any case. Make sure that the subwoofer's internal crossover does not fight with the signal sent by the receiver. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#4
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Thank you both (Learning & Mann). Some clarification from my end. - I KNOW the A/V output is MONO. - I have a Passive prebuilt SUB. - It is a Paradigm SB-100. Currently I don't have a stand alone amp for it, I am leaning towards running the SUB output of the A/V unit through a vintage Sony Receiver I have on the AUX input. My dilemma is wrapped around having both Left & Right binding posts on the bottom of the Sub cabinet. I'll likely ignore one side and just hook up one or the other only. TBerk |
#5
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T wrote:
Thank you both (Learning & Mann). Some clarification from my end. - I KNOW the A/V output is MONO. - I have a Passive prebuilt SUB. - It is a Paradigm SB-100. Currently I don't have a stand alone amp for it, I am leaning towards running the SUB output of the A/V unit through a vintage Sony Receiver I have on the AUX input. My dilemma is wrapped around having both Left & Right binding posts on the bottom of the Sub cabinet. I'll likely ignore one side and just hook up one or the other only. Does it also have L & R *output* terminals? If so, it probably has a dual coil subwoofer driver and passive crossover. It can be placed directly on the outputs of your amplifier, with your L&R front speakers connected to the subwoofer outs. The crossover will handle the job of filtering some of the low frequencies out of the main speakers and directing them to the sub...a workable solution, but inefficient...some power will be wasted in the crossover, and you might not want to filter the lows from your mains. ****Main amp speaker outssub insL&R speakers OR Main amp speaker outs parallel with sub ins and L&R speakers (possible impedance problem?)**** The setup you describe, using an auxiliary sub amp, will result in slightly more volume (assuming enough power output from that amp). Use a 'Y' cable (one RCA male to two RCA males) to route sub output from your main amp to the AUX ins on your sub amp, and connect the L&R speaker outs to your sub ins. ***Main amp sub out'Y' cableL&R sub amp AUX inssub amp L&R speaker outssub*** jak TBerk |
#6
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jakdedert wrote:
snip Use a 'Y' cable (one RCA male to two RCA males) to route sub output from your main amp to the AUX ins on your sub amp, and connect the L&R speaker outs to your sub ins. ***Main amp sub out'Y' cableL&R sub amp AUX inssub amp L&R speaker outssub*** jak MuHahahahahah. That was _exactly_ what I wanted to hear. It's just to get the thing a little run. I'll be picking out a dedicated stand alone amp down the line. Thx everybody. TBerk |
#7
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"T" wrote in message m... jakdedert wrote: snip Use a 'Y' cable (one RCA male to two RCA males) to route sub output from your main amp to the AUX ins on your sub amp, and connect the L&R speaker outs to your sub ins. ***Main amp sub out'Y' cableL&R sub amp AUX inssub amp L&R speaker outssub*** jak MuHahahahahah. That was _exactly_ what I wanted to hear. It's just to get the thing a little run. I'll be picking out a dedicated stand alone amp down the line. Check out PartExpress linear FET class AB sub amps. Nice units, good value - I have two in service (home theatre and stage piano keyboard) .. BTW, I have no connection with this company. Cheers, Roger |
#8
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Engineer wrote:
"T" wrote in message m... jakdedert wrote: snip Use a 'Y' cable (one RCA male to two RCA males) to route sub output from your main amp to the AUX ins on your sub amp, and connect the L&R speaker outs to your sub ins. ***Main amp sub out'Y' cableL&R sub amp AUX inssub amp L&R speaker outssub*** jak MuHahahahahah. That was _exactly_ what I wanted to hear. It's just to get the thing a little run. I'll be picking out a dedicated stand alone amp down the line. Check out PartExpress linear FET class AB sub amps. Nice units, good value - I have two in service (home theatre and stage piano keyboard) . BTW, I have no connection with this company. Cheers, Roger Yeah, they seem to get a lot of recommendations. I have know of them for awhile but just recently when i got up the gumption to build a sub (and hence buy one of those amps) a friend dropped this passive prebuilt sub on me for free so I was going to hook it up and give it a run to see what I was working with. Thx everybody, TBerk |
#9
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T Apr 14, 4:45 am show options
Newsgroups: rec.audio.tech From: T Some clarification from my end. - I KNOW the A/V output is MONO. - I have a Passive prebuilt SUB. - It is a Paradigm SB-100. Currently I don't have a stand alone amp for it, I am leaning towards running the SUB output of the A/V unit through a vintage Sony Receiver I have on the AUX input. My dilemma is wrapped around having both Left & Right binding posts on the bottom of the Sub cabinet. I'll likely ignore one side and just hook up one or the other only. TBerk T: Just go to www.svssubwoofers and click on amps and EQ's. You find 2 Sampson amps that shoudl do very nicely for your sub. I think best results would be obtained by adding an electronci xover and parametric EQ, to flatten out the response. |
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