Stereo rig with (2)JBL D-130 16 ohm speakers

Lefty · Post by **Lefty** » 29 Jul 2003 6:06 pm

I am considering putting a stereo amp rig together with some equipment I have around.
These include a pair of 16 ohm D-130 JBL's (pristine) I got out of stereo cabinets that were my father in laws, and were set to be yard sell material. I have a Yamaha PC2002 power amp and was wondering the effects of trying to run twin stereo cabinets @ 16 ohms.
I would need a good stereo pre-amp. The amps specs only discuss running stereo @ 8 ohms 120 watts per channel stereo, 16 ohms @ 240 watts per channel mono, or 8 ohms @ 350 watts per channel mono. If anyone has experimented with this, Please comment on the effects of trying to run stereo @ 16 ohms.
Thanks,
Lefty
[This message was edited by Lefty on 29 July 2003 at 07:08 PM.]

Bill Crook · Post by **Bill Crook** » 30 Jul 2003 5:12 am

The amps specs only discuss running stereo @ 8 ohms 120 watts per channel stereo, 16 ohms @ 240 watts per channel mono, or 8 ohms @ 350 watts per channel mono. If anyone has experimented with this, Please comment on the effects of trying to run stereo @ 16 ohms.

I may be sticking my foot in my mouth,but I think that as the ohm's go up, the watts go down..... Also,as the ohmage goes up the over-all sound will seem to go toward a more "Bass" sound. That is: we loose the "Hi's" in the overall scheme of things.

Based upon my thinking, .... If you had a 8 ohm transducer (speaker)doing 120 watts,and you changed it to a 16 ohm unit,the total output of the 16 ohm device would be about 1/2 (60 watts) of rated output.

Now if the the out-put should be rated at 4 ohms,and you placed a 16 ohm speaker there, the effective output would be far somewhat less than the desired results.

1) As any Electronic Tech will admit... The math don't add up.
2) The resultant sound WILL be that the sound can only be loss of "Highs" and a more "bass" sound.

I have found that in my "Profex II", I have had to change a few of the Peremiters so that I can re-gain the "Hi's" due to a loss of freq responce of the speaker device,and other settings with-in the "Profex II" device,in order to bring the desired (overall) freq responce back to a level I can live with,The speaker is a indepentant device that dosen't really dosen't stand up to the "Electronics" part of the theory,so therefore we need to adjust the over-all theory to suite our desires and needs.

Bill

Larry Bell · Post by **Larry Bell** » 30 Jul 2003 6:14 am

Lefty,
You're in no danger of blowing anything up, so just plug 'em in and see what they sound like. Can't hurt nothin', and then you'll know. Yes, the output will be lower and it is possible that you will lose some highs, but it might sound good. I agree with Bill that the numbers sound a bit screwy, but a good solid 80 or 100 watts per side is way more than I usually use for gigs. I often play through a single 100 watt amp with plenty of headroom. You may be pleasantly surprised.

------------------
Larry Bell - email: larry@larrybell.org - gigs - Home Page
2003 Fessenden S/D-12 8x8, 1969 Emmons S-12 6x6, 1971 Dobro, Standel and Peavey Amps

Brad Sarno · Post by **Brad Sarno** » 30 Jul 2003 6:56 am

Those numbers seem to make sense since they are showing both stereo operation and bridged mono operation. From those numbers stating that the amp is 120 watts at 8 ohms in stereo (dual mono). My guess is that the amp will probably give you 80 watts per channel into a stereo pair of 16 ohm speakers, using the amp in stereo. That's a total of 160 watts into JBL's which are very efficient so it'll be loud.

If you arent using "stereo" effects, you could bridge the amp to mono and wire the speakers in parallel. This would put an 8 ohm load on the amp bridged to mono giving you the full 350 watts. Super loud...

------------------
Brad Sarno
Blue Jade Audio Mastering
St. Louis

Lefty · Post by **Lefty** » 31 Jul 2003 1:01 am

Thanks to all for the information/advice. I think I will just have a go at it.
Lefty