Riffster Posted September 5, 2015 Posted September 5, 2015 I know there are a couple of you here that have years of experience on audio/video installation and I have a question. I have an NAD 7240 audio receiver that does not have a subwoofer out RCA so the only way to connect my powered subwoofer is to use the speaker terminals in it. In and then out. The issue I have is I have a very tight setup for my audio, (shelf speakers), running cables to the subwoofer is easy but I cannot hide the cables going out from the subwoofer to the speakers. The question is, can I run cables to the subwoofer and connect the speakers normally? so all cables would be connected to the speaker terminals of the receiver. Since the subwoofer is powered I would imagine there isn't an impedance issue. Also if it is possible, does the subwoofer really need the two sets of wires? right and left?
L5Larry Posted September 5, 2015 Posted September 5, 2015 ... Since the subwoofer is powered I would imagine there isn't an impedance issue. DO NOT connect your "powered" sub to the amplified speaker out connections, you will fill the room with all that magic smoke that make electronics work. Your local Fire Department might even need to be involved. The amp in your sub is designed to run on preamp "line voltage" (speaker "impedence" does not even factor into this equation). The speaker terms on your receiver push "high voltage". You will either blow the amp in your sub, blow the amp in your receiver, both, and/or burn your house to the ground (I'm not kidding). If you have "record out" jacks, say a send to a cassette deck, this would be the correct type line level output, but.... Without a proper and dedicated preamp line level "line out to subwoofer" connection, meaning not only is it the proper line level voltage, but also crossover filtered to send/receive only the specific bass frequencies, you will get nothing but mush out of the speaker anyway. Sounds like it's time for you to get a new 5.1 surround sound receiver. A nice one can be had these days for under $200.
Riffster Posted September 5, 2015 Author Posted September 5, 2015 Well, the subwoofer does have connections for speaker in and then out, so you run your speakers through it, the subwoofer gets what it needs and then the speaker connection continues from there. It is designed this way precisely for receivers that do not have a Pre-out or LFE out, all I have to do is flip a switch in the back. This is the way it is instructed in the manual to connect it. I am just wondering if there is a "series vs parallel" connection that I can use. Or I will have to relocate the subwoofer to a less ideal locaiton in the room. I have a 7.1 receiver too, it has the standard sub-pre out RCA. I've had it for 10 years but it does not hold a candle to my NAD receiver for music. I was just trying to get that subwoofer bass.
flyingarmadillo Posted September 6, 2015 Posted September 6, 2015 ... Or I will have to relocate the subwoofer to a less ideal locaiton in the room... Subs are pretty non-specific as to location - at 65Hz the wavelength is still ~17.5 feet - bigger than the average room so it won't localize the sound. The phase is more critical than the location.
J.4knee Posted September 6, 2015 Posted September 6, 2015 Does your receiver have preamp out? If so connect the sub to it.
Guest Farnsbarns Posted September 6, 2015 Posted September 6, 2015 DO NOT connect your "powered" sub to the amplified speaker out connections, you will fill the room with all that magic smoke that make electronics work. Your local Fire Department might even need to be involved. The amp in your sub is designed to run on preamp "line voltage" (speaker "impedence" does not even factor into this equation). The speaker terms on your receiver push "high voltage". You will either blow the amp in your sub, blow the amp in your receiver, both, and/or burn your house to the ground (I'm not kidding). If you have "record out" jacks, say a send to a cassette deck, this would be the correct type line level output, but.... Without a proper and dedicated preamp line level "line out to subwoofer" connection, meaning not only is it the proper line level voltage, but also crossover filtered to send/receive only the specific bass frequencies, you will get nothing but mush out of the speaker anyway. Sounds like it's time for you to get a new 5.1 surround sound receiver. A nice one can be had these days for under $200. The sub has speaker inputs for each speaker so it will, in fact, be designed to take the speaker voltage into an active crossover, keeping the low range and passing the higher range on to the other speakers. There's probably also a pot for changing the range which would be set by ear and depends on the other speakers and the room. It won't blow anything up and this is the better way to use it. You will need to connect all the speakers the same otherwise some will recieve the low frequencies and others won't. It'll sound horrible and unbalanced. You will also have missing low end on any low frequencies sent to one speaker only. This is a particular issue with surround sound sources. You should separate the woofer and the centre speaker as much as you can if it's surround sound btw.
SteveFord Posted September 6, 2015 Posted September 6, 2015 http://nadelectronics.com/products/hifi-receivers/7240PE-Stereo-Receiver/ This will describe how to use the preamp output so you can run your speakers full range. Set the sub's crossover at the point where your speakers peter out. For my Magnepans I use 25-40 Hz depending on the model.
Riffster Posted September 6, 2015 Author Posted September 6, 2015 Thanks guys this is what I was looking for. I was wondering if running the speakers through the subwoofer would remove so me bass and I don't want that. Looks like farns comments make sense. The preamp out seems the right answer since I want the subwoofer to pickup where my speakers bass drops off. My speaker system is not high quality but they fit the room and do the job. Once my daughter grows I will probably buy a nice set of towers. I am not sure what kind of frequencies my subwoofer I capable of but it does add some nice bass to audio. The frequencies to select from in the front panel seem high to me.
Riffster Posted September 6, 2015 Author Posted September 6, 2015 http://nadelectronics.com/products/hifi-receivers/7240PE-Stereo-Receiver/ This will describe how to use the preamp output so you can run your speakers full range. Set the sub's crossover at the point where your speakers peter out. For my Magnepans I use 25-40 Hz depending on the model. That's nice and low, I bet those Magnepans sound great.
SteveFord Posted September 6, 2015 Posted September 6, 2015 I got hooked on them around 23 years ago and never felt the need to switch speaker brands. They're upstairs, downstairs and used for television and movies, too. If those crossover buttons are on the front of your sub all I can suggest is to experiment and see which sounds the best to you. Every system, room and pair of ears is different. P.S. I was given an NAD 3020 which is basically your same unit but without the tuner. I use that for headphone duty and it sounds great. It has that warm British sound quality so I don't think you're going to need much bass output from a subwoofer, maybe just a bit to fill out where your speakers leave off.
Riffster Posted September 7, 2015 Author Posted September 7, 2015 Very nice, Since I already have the subwoofer I am trying to see if it will improve my current setup. In reality the speakers I have are borderline bookshelf speakers since they have 8" woofers, bass is good but a subwoofer adds in certain cases. The NAD receiver actually has a button called Bass EQ which is supposed to mimic a subwoofer up to a point but it is either on or off. It also has a Loudness button but I only use it when I am running low volume to get that fuller sound. My speakers are Aiwa so their just a bit better than Sony or Panasonic but I really like them and fit my space and needs for now. I found a link on CNET that seems to suggest what I suspected, connecting the subwoofer directly to the speaker outputs and run the speakers from there at the same time rather than running the main speakers through the subwoofer crossover. http://www.cnet.com/how-to/how-to-hook-up-a-subwoofer-to-a-stereo-system/ These NAD receivers are great, they go for so cheap used on eBay. My Sony receiver is a 7.1 top-ish of the line model and does not old a candle to the NAD, especially the Phono preamp...even the radio sounds far better.
SteveFord Posted September 7, 2015 Posted September 7, 2015 My preamps have the INPUTS where you hook up the turntable, tuner, CD player, etc. Then you have the OUTPUTS for the amplifiers. I run RCA cables from one set of OUTPUT jacks on the preamp to the LOW LEVEL INPUT jacks on the subwoofer. No speaker wires are involved. Maybe contact NAD and ask them what they'd recommend?
Riffster Posted September 7, 2015 Author Posted September 7, 2015 Yea, I may contact them. I do get your suggestion and prefer it since it'd be a more pure signal going to the subwoofer. The thing is this receiver only has one set of preamp outputs and one set of inputs so I need to run a cable that would allow the signal to go to the subwoofer single RCA input but also to continue the signal to the power section of the amp. I am sure there is a cable that meets that need.
SteveFord Posted September 7, 2015 Posted September 7, 2015 http://www.parts-express.com/parts-express-gold-rca-y-(1)-male-to-(2)-right-angle-female-black--091-515
Guest Farnsbarns Posted September 7, 2015 Posted September 7, 2015 Yea, I may contact them. I do get your suggestion and prefer it since it'd be a more pure signal going to the subwoofer. The thing is this receiver only has one set of preamp outputs and one set of inputs so I need to run a cable that would allow the signal to go to the subwoofer single RCA input but also to continue the signal to the power section of the amp. I am sure there is a cable that meets that need. http://www.parts-express.com/parts-express-gold-rca-y-(1)-male-to-(2)-right-angle-female-black--091-515 That'll do nicely. Actually, that gives me an idea! My next amp might just have a 2 spring and a 3 spring reverb tank. I'll need to re-amplify both separate, now I need to find a bigger power tranny. D'oh!
Riffster Posted October 4, 2015 Author Posted October 4, 2015 My preamps have the INPUTS where you hook up the turntable, tuner, CD player, etc. Then you have the OUTPUTS for the amplifiers. I run RCA cables from one set of OUTPUT jacks on the preamp to the LOW LEVEL INPUT jacks on the subwoofer. No speaker wires are involved. Maybe contact NAD and ask them what they'd recommend? Thanks by the way, that worked. I bought an RCA patch cable, plugged it between the preamp and amp and the subwoofer works great.
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