AudioCircle

Audio/Video Gear and Systems => The Lab => Topic started by: fado on 13 Oct 2019, 08:33 pm

Title: Hooking up two pairs of speakers to the same amplifier?
Post by: fado on 13 Oct 2019, 08:33 pm

I know there are 100 reasons why this will not improve sound quality but I just want to do it for fun - WITHOUT BREAKING ANYTHING. I just got a new pair of speakers and want to play them with my old ones still hooked up.

New speakers:  96 db, 6 ohms
Old speakers:  95.5 db, 8 ohms

Amplifier: 150 watts/channel

I would just hook up a separate set of speaker cables to the amplifier along with the speaker cables already hooked up to my old speakers.

Thanks

Title: Re: Hooking up two pairs of speakers to the same amplifier?
Post by: Elizabeth on 13 Oct 2019, 08:46 pm

If the speakers are hooked up as you suggest, then the impedance the amplifier sees will be around 3.43 ohms. (( https://www.allaboutcircuits.com/tools/parallel-resistance-calculator/ ))
THe problem is, the '6' and '8' are only nominal.. each speaker may at some part of the audio spectrum drop to less. even down to 3 ohms.. and being combined the amplifier 'may' see a resistance in some music of only a few ohms total.
So yes you can do it CAREFULLY. Which means not too loud. and keep track of HOW HOT the amp is getting.

On the other hand, if you wire the speakers in series. then the total impedance is going to be 14 ohms. which is pretty safe to crank up the amp with. (I am not going to fully explain what you have to do to wire in series unless you really really need me to!)

Title: Re: Hooking up two pairs of speakers to the same amplifier?
Post by: mix4fix on 13 Oct 2019, 09:18 pm

What amplifier is it?

Title: Re: Hooking up two pairs of speakers to the same amplifier?
Post by: fado on 13 Oct 2019, 09:23 pm

Modwright KWA 150SE
Speakers are Daedalus DA-RMa and Apollo 11

Title: Re: Hooking up two pairs of speakers to the same amplifier?
Post by: aldcoll on 13 Oct 2019, 09:36 pm

I hooked up a pair of Appollos and Pans with my KWA 150 for a short hour or less. 

Probably not recommended but fun???

The sound wasnt any better as the sound stage is lost with them next to each other.  Just a big wall of sound.

I actually pulled out a old NAD 7400 and used the A B switch.  Fun factor 10, calling for service about 4 to 7.

Title: Re: Hooking up two pairs of speakers to the same amplifier?
Post by: fado on 14 Oct 2019, 12:16 am

Thank You all - decided not to do it.

Title: Re: Hooking up two pairs of speakers to the same amplifier?
Post by: FullRangeMan on 14 Oct 2019, 12:23 am

Some amps have a output circuit that dont work below 4 ohms, found the Hartke HA2400 is one of them :duh:

Title: Re: Hooking up two pairs of speakers to the same amplifier?
Post by: richidoo on 14 Oct 2019, 03:37 am

You could measure the load of both speakers in parallel with a tool like DATS (https://www.parts-express.com/dayton-audio-dats-v3-computer-based-audio-component-test-system--390-807) or woofertester to know for sure what the amp would see. This (https://www.audioholics.com/loudspeaker-design/understanding-impedance-electrical-phase/page-2) explains reactive speaker load in more detail.