Cam I use receiver amp to drive subwoofer?


Curious Newbie
Unregistered guest
Hi all !

I am building my own subwoofer. I want to know if I can power a rated 4 ohm subwoofer (500 watt max) with an old receiver I am not using.

My receiver is rated Kenwood kr-797:
110 W: 40-20000Hz .8% THD @8 ohms according to manual specs.

Can I power the 4 ohm driver (and only that driver) or will my amp die.

Eventually I will buy a subwoofer amp, but I want to drive the woofer in the mean time.

Curious Newbie ;)

New member
Username: Gman

Post Number: 122
Registered: 12-2003
I am not familiar with this receiver and what kind of headroom it has and whether it even has the ability to play 4 ohm full range speakers. If you have the manual or if it has a 4 ohm switch on the back this will clue you in.

Not too many modern receivers have the ability to drive with sufficient oomph and clarity full range 4 ohm speakers when played loudly before overheating and blowing a fuse, clipping, and/or causing damage. Some of the older receivers had better amp sections, but unless you have the manual and could see any 4 ohm specs you are travelling on dicey territory.

8 ohm subs draw plenty of power--4 ohm subs draw a lot more. This could easily blow a fuse if you are lucky, or cause much more damage than that.

I would e-mail Kenwood tech dept, but I am confident they will recommend you get the subwoofer amp that is adequate for driving a 4 ohm subwoofer.

There are a number of DIY sites that will tell you your minimum needs.

New member
Username: Stez_head

Post Number: 18
Registered: 01-2004
You can do it easy all you have to do is brige the subwoofer on the front or main channel and your kenwood amp can handle 4 Ohms easily because your sub will only draw in about 50w RMS which is average your amp will handle is perfectly just watch the base and volume.

Unregistered guest
Can someone explain to me what the Frequency and Equalizers do on the amp. Im trying to adjust my amp settings and Im Lost!

Silver Member
Username: Gman

Post Number: 260
Registered: 12-2003
If you have an equalizer on your preamp or receiver, than you can adjust the frequencies that the equalizer has adjustments on. Normally, a person will buy an SPL Meter and sit in their favorite listening spot and generate "pink noise" at the frequencies that the equalizer generates. With the equalizer you can adjust those frequencies so that the SPL's are all equal where you are sitting. This helps acoustically balance the speakers.

Of course, to do a really great job you'd need a separate expensive parametric equalizer that goes from 20Hz to 20KHz and have the "pink noise" generator work throughout the range. Most receiver equalizers leave out the frequencies below 250 Hz---and mostly those frequencies are the ones significantly out of whack.

Silver Member
Username: Hawk

Post Number: 387
Registered: 12-2003

You certainly can do it, although as G-Man points out there are a lot of questions about the Kenwoods ability to do a decent job (ability to handle 4 ohm speaker driver, is the receiver's amp bridgeable, etc.). However, for very little money, you can go ahead and get a good subwoofer amp that will drive a 4 ohm speaker, like these here: Group_ID=505

You will note thay have three different subwoofer amps priced less than $100, and all are 4 ohm capable. More importantly, they will have a high and low pass filters built in, which your Kenwood certainly does not have. BTW, Parts Express also has subwoofer cabinets that you can purchase and will hold both your subwoofer driver and the sub amp. It makes sense, if you are building a sub, to get the essential parts up front.

Good luck!

Unregistered guest
Since you have a 797, Can you adjust the volume of the rear surround speakers? Just wondering, my friend has one and i just hooked up a JBL surround on his receiver and can't get much volume out of the rears. He has no remote and was wondering if this model had this option. And it so, how do you do it on just the receiver???
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