Subwoofer connection

R

Rbloom659

Enthusiast
Hi - I am considering adding a subwoofer to my system but there is no provision for this on my somewhat dated equipment. My preamp is a Hafler model 100 with conventional outputs going to a SAE power amp with simply "Channel A & Channel B" outputs to the speakers. Is there a way to do this without sacrificing sound quality or must I commit to new equipment? I am very happy with what I have - I just want more bass. Thanks for any help on this..
 
W

Willow

Audioholic Intern
you can run speaker cables from your receiver to the back of the sub then from the sub out to the speakers
good luck
 
B

bgeiger

Audiophyte
You only want to run speaker wire to the sub IF it has a speaker level input. Many don't. Your best option is to get a line level converter. You input speaker level signals in one side, and line level signals come out the other. Easy to hook-up and inexpensive. Also, if your sub has L & R inputs, you can split the L & R pre-outs with a "Y" cable, and send one branch to the sub and one to the amp...
 
dsa220

dsa220

Junior Audioholic
I would take it by your post that you do not have a sub at the moment, but are lookingt to get one. If this is indeed the case, then before you purchase your sub check out the connections on the back.

There are three ways (and thoughts) on how to hook up a sub:

1 - Most subs will have a line in and a line out using the same type of cables that you presently use to connect your pre-amp to you amp. Simply get another set of cables, then go from your pre-amp output to your 'line in' (or 'sub in', whatever it is labeled), the go from the 'line out' on the sub to your main amplifier. Be careful to maintain proper polarity (left to left, right to right). Most subwoofer do not have a true crossover built in, so your speakers will still be running full range; the crossover setting just determines the upper frequency of the sub.

Some subs do have built in cross-overs, like my REL Stratta II, but not all do. Look at the documentation (or manual) before you buy if this is going to be important to you.

2 - If the sub has speaker level (ususally called 'hi level') inputs, then simply run an additional pair of speaker wire from your amp to your sub, leaving the speakers still connected to your main speakers as they already are. Again, you main speakers will still be running full range.

3 - Get an external electronic cross-over. You would then go from you pre-amp to the cross-over, the crossover would then 'split' the signal, with the low frequency going to the sub and the higher frequency (as determined by the cross-over) going to your current amplifier. The benefit of this method is that now your main speakers (or amlifier) do not have to reproduce deep bass, that is what the sub is for, and you should see [potentially] an increase in dynamics, power and resolution.

Everybody has their favorite method, with method 3 being the most popular. My 2-channel set-up uses method 2 with a very low cross-over point on the sub (30 Hz). That was the best blend that I found after several weeks of playing around.

Whichever way you go, a good sub on a 2-channel rig can make a big difference in overall sound. When properly set-up, you will wonder how you ever lived without one. Just remember, 2 things, subs are not just for HT and the best sounding sub is the one you don't hear, that is until it is turned off.
 
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M

Mr.T

Audioholic
RBloom, if this receiver has only two channels A+B, it has to be real old.
I personally would start saving money for a new one, instead of investing money on a subwoofer now that you might won't like it any longer when you're ready to buy a new system.

Don't forget Christmas is around the corner, who knows what Santa Clause will bring you this Holiday Season if you start complaint to your family and friends that your HT is not pleasing you any longer. You'll never know you might get lucky!!

Mr.T
 
R

Rbloom659

Enthusiast
dsa220 said:
I would take it by your post that you do not have a sub at the moment, but are lookingt to get one. If this is indeed the case, then before you purchase your sub check out the connections on the back.

There are three ways (and thoughts) on how to hook up a sub:

1 - Most subs will have a line in and a line out using the same type of cables that you presently use to connect your pre-amp to you amp. Simply get another set of cables, then go from your pre-amp output to your 'line in' (or 'sub in', whatever it is labeled), the go from the 'line out' on the sub to your main amplifier. Be careful to maintain proper polarity (left to left, right to right). Most subwoofer do not have a true crossover built in, so your speakers will still be running full range; the crossover setting just determines the upper frequency of the sub.

Some subs do have built in cross-overs, like my REL Stratta II, but not all do. Look at the documentation (or manual) before you buy if this is going to be important to you.

2 - If the sub has speaker level (ususally called 'hi level') inputs, then simply run an additional pair of speaker wire from your amp to your sub, leaving the speakers still connected to your main speakers as they already are. Again, you main speakers will still be running full range.

3 - Get an external electronic cross-over. You would then go from you pre-amp to the cross-over, the crossover would then 'split' the signal, with the low frequency going to the sub and the higher frequency (as determined by the cross-over) going to your current amplifier. The benefit of this method is that now your main speakers (or amlifier) do not have to reproduce deep bass, that is what the sub is for, and you should see [potentially] an increase in dynamics, power and resolution.

Everybody has their favorite method, with method 3 being the most popular. My 2-channel set-up uses method 2 with a very low cross-over point on the sub (30 Hz). That was the best blend that I found after several weeks of playing around.

Whichever way you go, a good sub on a 2-channel rig can make a big difference in overall sound. When properly set-up, you will wonder how you ever lived without one. Just remember, 2 things, subs are not just for HT and the best sounding sub is the one you don't hear, that is until it is turned off.
dsa220, I like that idea, but am having a little trouble finding the crossover for home audio use. There seems to be a lot of car audio crossovers out there. Any suggestions?
 
R

Rbloom659

Enthusiast
Any recommendations for an "external electronic crossover? There seems to be a lot of car stuff out there, but not necessarily anything designed for home use...
dsa220 said:
I would take it by your post that you do not have a sub at the moment, but are lookingt to get one. If this is indeed the case, then before you purchase your sub check out the connections on the back.

There are three ways (and thoughts) on how to hook up a sub:

1 - Most subs will have a line in and a line out using the same type of cables that you presently use to connect your pre-amp to you amp. Simply get another set of cables, then go from your pre-amp output to your 'line in' (or 'sub in', whatever it is labeled), the go from the 'line out' on the sub to your main amplifier. Be careful to maintain proper polarity (left to left, right to right). Most subwoofer do not have a true crossover built in, so your speakers will still be running full range; the crossover setting just determines the upper frequency of the sub.

Some subs do have built in cross-overs, like my REL Stratta II, but not all do. Look at the documentation (or manual) before you buy if this is going to be important to you.

2 - If the sub has speaker level (ususally called 'hi level') inputs, then simply run an additional pair of speaker wire from your amp to your sub, leaving the speakers still connected to your main speakers as they already are. Again, you main speakers will still be running full range.

3 - Get an external electronic cross-over. You would then go from you pre-amp to the cross-over, the crossover would then 'split' the signal, with the low frequency going to the sub and the higher frequency (as determined by the cross-over) going to your current amplifier. The benefit of this method is that now your main speakers (or amlifier) do not have to reproduce deep bass, that is what the sub is for, and you should see [potentially] an increase in dynamics, power and resolution.

Everybody has their favorite method, with method 3 being the most popular. My 2-channel set-up uses method 2 with a very low cross-over point on the sub (30 Hz). That was the best blend that I found after several weeks of playing around.

Whichever way you go, a good sub on a 2-channel rig can make a big difference in overall sound. When properly set-up, you will wonder how you ever lived without one. Just remember, 2 things, subs are not just for HT and the best sounding sub is the one you don't hear, that is until it is turned off.
 
dsa220

dsa220

Junior Audioholic
Sorry for the delay in responding (I was out of town for two weeks, unfortunatly it was business and not pleasure :D ).

There are many crossovers out there, do a google serach sometime or check out sites like Audiogon.

Here is a link to a good company:

http://www.marchandelec.com/xovers.html

They sell them pre-assembled or in kits. I have built a few for some friends and find them to be quite good (and quiet). Good stuff!!!

Check them out and let us know what yuou think.
 
M

markw

Audioholic Overlord
Don't forget...

You'll also need some capability to "merge" the two channels into one subwoofer channel while still maintaing each channel as a separate entity.

Unless I missed something, Marchand, while quite comprehensive, did not offer this.

You're best bet is simply buying a subwoofer with the needed R/L inputs to start with. You can then easily split the preamp out signals wih cheap "Y" connectors and feed it's signal to both the power amp AND the sub's line level inputs without a worry (and no signal degradation).
 
dsa220

dsa220

Junior Audioholic
You'll also need some capability to "merge" the two channels into one subwoofer channel while still maintaing each channel as a separate entity.
Most subs have two inputs (left & right - at least the four in my home do). It is a very rare sub that has only one input.

MarkW, you may be thinking of the LFE channel used for HT, I do not believe that this is the case here, this is a simply a 2.0 configuration (I believe).
 
M

markw

Audioholic Overlord
Yes, this is true.

dsa220 said:
Most subs have two inputs (left & right - at least the four in my home do). It is a very rare sub that has only one input.

MarkW, you may be thinking of the LFE channel used for HT, I do not believe that this is the case here, this is a simply a 2.0 configuration (I believe).
But, then again, most powered subs also have built in crossovers as well as power amps. Again, this is all determined by what powered sub he buys and yes, there ARE some out there with only one input.
 
WorkerBee

WorkerBee

Junior Audioholic
Hi,
Before I bought a sub it was all very confusing too but now that I have one it seems quite simple :) There seems to be a few different ways to do it.
My Denon #685 "stereo" reciever has A&B speaker posts. I just run my sub hooked up to the (B) set, two red & two black posts.

Good Luck....the guy's around here are pretty knowledgable..I'm still learning a lot. :D
 
dsa220

dsa220

Junior Audioholic
MarkW

But, then again, most powered subs also have built in crossovers as well as power amps. Again, this is all determined by what powered sub he buys and yes, there ARE some out there with only one input.
I thought I said that in my original response, see quote below from that response:

Most subwoofer do not have a true crossover built in, so your speakers will still be running full range; the crossover setting just determines the upper frequency of the sub.

Some subs do have built in cross-overs, like my REL Stratta II, but not all do. Look at the documentation (or manual) before you buy if this is going to be important to you.
Of the four subs that I currently own, only one has a true cross-over in it, and that is my REL [Stratta II], the other three allow the signal to run full range to the main amp/speakers with the frequency control on the back determining the upper frequency limit for the sub.

Agreed, there are some subs that have a single input, but these tend to be (but not always) pro units that are normally used in mix-down rooms for movies or in studios. Most subs for home use normally (again, not always) have a L/R input on them. Only the documentaion will tell you if it has a true cross-over in it or not, but it has been my experience that most do not.
 
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M

markw

Audioholic Overlord
I run my sub from 50 hz and below and let my speakers run full range. What they can't reproduce, they simply ignore. Again, if he really, really wants a high pass filter many subs allow this also. Velodynes do and I'm pretty sure others do as well.

Either way, methinks someone is overcomplicating this matter.
 
R

Rbloom659

Enthusiast
Thanks for all your help on this, everyone - the article posted on this site states that one MUST be prepared to disconnect the crossover in the existing speakers to properly biamp. That idea doesn't thrill me, and I am not sure I really can. For info's sake, we are talking about a pair of 1990ish DCM Timeframe 250's - about 250 - 300 dollars a pair back then. Any thoughts on this? Thanks again!
 

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