Mixing 4 and 8 ohm speakers

SiddPolk

Tweeter out my way is closing their stores, and offering fantastic deals on Polks, so I picked up a pair of RTiA5s, RTi8s (from somewhere else), a single RTiA3 and an LSiC. Didn't realize the LSiC is 4 ohms until I got it home. For power I'm using an Onkyo 805 and Parasound 2250. With the speaker ohm issue, I'm currently bi-amping the RTiA5 fronts with the onk, driving the rear RTi8s with the onk, and routing the center through the Parasound right channel to the LSiC.

So I've got a couple of questions.
1. The Onkyo has a setting for 4 ohm and 6 ohm. If memory serves, you're supposed to have it set on 6 ohm for 8 ohm speakers ... so it doesn't sound like a good thing for the onk to mix in a 4 ohm. Anybody know about this?
2. I didn't want to bridge mono the Parasound for the LSiC, too much wattage and kids in the house. So I'm running a normal stereo setting, but only using the right channel. Will this cause a problem with the Parasound?
3. Any ideas I'm all ears.

acsubie

im using my Onkyo 805 to power my rear surround emotivas(4ohm) speakers, the rest of my RTi 7.1 setup(8ohm) is being seperately amplified by an emotiva XPA, since i am running only a single set of 4ohm speakers through the Onkyo i am not worried about the power consumption, the onkyo IS set to the 4ohm setting

i was in the market for the LSi series and if you dont mind me asking what you end up picking the LSic for?

mmadden28

I'm pretty sure you shouldn't be mixing 4 and 8 ohm speakers on the same amp/avr.

Besides you really want to timbre match your front stage. Although some have done it and like it, mixing the RTi and LSi series for the fronts is not recommended.

Wlecome to Club Polk!!

SiddPolk

acsubie wrote: »

im using my Onkyo 805 to power my rear surround emotivas(4ohm) speakers, the rest of my RTi 7.1 setup(8ohm) is being seperately amplified by an emotiva XPA, since i am running only a single set of 4ohm speakers through the Onkyo i am not worried about the power consumption, the onkyo IS set to the 4ohm setting

i was in the market for the LSi series and if you dont mind me asking what you end up picking the LSic for?

Thanks for the reply. The LSiC was only 268 w/ tax. It was a display model, but tweeter is a fully authorized Polk dealer ... that's why I couldn't pass it up.

SiddPolk

mmadden28 wrote: »

I'm pretty sure you shouldn't be mixing 4 and 8 ohm speakers on the same amp/avr.

Besides you really want to timbre match your front stage. Although some have done it and like it, mixing the RTi and LSi series for the fronts is not recommended.

Wlecome to Club Polk!!

Thanks, that's what I thought with the 4 and 8 ohm. I originally had it all powered by the 805, and it didn't sound up to snuff for lack of a better term. With the bi-amp on the fronts and parasound on the LSiC, they sound good ... actually they sound fantastic. I normally would pass on a non-matched center except that the quality on the LSiC was too good and the price was too low.

Know anything about running a single channel on the Parasound only, without being bridged?

mmadden28

SiddPolk wrote: »

... actually they sound fantastic. I normally would pass on a non-matched center except that the quality on the LSiC was too good and the price was too low.
...

I hear ya on mixing. I considered it myself when I was first setting my system up, I had the ability to get an LSiC on the cheap, but having not heard the combo and all the comments about not doing kept me from going that way. I'm glad I didn't though as I am very happy with the CSi6a-I would have always wondered what i might have been missing without a matched center. Besides the Csi matches my speakers and Entertainment center so well.

Well as long as it sounds good to you is all that matters. And getting a good deal is a bonus.

SiddPolk

mmadden28 wrote: »

I hear ya on mixing. I considered it myself when I was first setting my system up, I had the ability to get an LSiC on the cheap, but having not heard the combo and all the comments about not doing kept me from going that way. I'm glad I didn't though as I am very happy with the CSi6a-I would have always wondered what i might have been missing without a matched center. Besides the Csi matches my speakers and Entertainment center so well.

Well as long as it sounds good to you is all that matters. And getting a good deal is a bonus.

Yes, thanks. I've owned mismatched, and matched before and matched is a no-brainer. I actually went to buy a CSi6 but it sold before I got there. The LSiC was available and cheap so I jumped on it. After the Audissy eq is done, I'll know for sure whether it stays or goes. However, right now the three fronts sound great. I should note that they didn't sound that great when being driven by just the onk ... only after I biamped the fronts and ran the LSiC off the parasound did they come together (I also upgraded the wires too). The difference was remarkable:eek:.

All the best

rivrbyte

I'm joining the pawteee here....
ok, I'm the confused one, or one of many... first about AVR's and getting either the ONKYO 606, 705,or the 706, I thought these AVR's run 8-ohms and you could not mix the 8's with 4's and even 6's.


I've been looking at 8-ohms speakers, and thought the 4 and 6-ohm's were for high end receivers, Is this so?

SiddPolk

rivrbyte wrote: »

I'm joining the pawteee here....
ok, I'm the confused one, or one of many... first about AVR's and getting either the ONKYO 606, 705,or the 706, I thought these AVR's run 8-ohms and you could not mix the 8's with 4's and even 6's.


I've been looking at 8-ohms speakers, and thought the 4 and 6-ohm's were for high end receivers, Is this so?

Yea, I just looked at the 606 and it's only rated down to 6 ohms. I'm no expert, but I haven't noticed 4 ohms vs 6 or 8 being any indicator to speaker quality. Since an ohm is simply a measure of electrical resistance, it's probably just a characteristic of the drivers and circuity used in the speaker .. or in other words, how efficient the speaker is with using the electricity. I don't know whether it means anything to sound quality having different ohm rated speakers on the same amp, or if it puts the amp in a higher risk of failure situation either. That was one of my questions.

mmadden28

Every speaker is different-depends on its design. Typically rated at 4 or 8 ohms. In reality under load and depending on the frequency the speaker impedance changes. The LSi9s are rated as 4 ohm speakers, but under load they can dip below 2 ohms.

The AVRs and Amps are all designed individually as well. Not all amps/avrs can handle the higher current loads of low imedance speakers. Somce can but need to be set that way. Such as the Onk 805 has a

mmadden28

^^ whoops sent too soon.
as I was saying, the Onk 805 has a setting for the Impedance of the speakers you will be using. The low setting is 6ohms, but they are rated to drive 4 ohm loads.
IIRC it does something internally to allow for the proper current flows but I'm not sure what.

Now when you're using your preamp outs to an external higher end or high current capable amp, there is no impedance switch (on any that I use anyway) so they may be better suited to handle multiple different impedance loads at the same time. I would say that is probably manufacture dependent though.
I don't run this way now, but IIRC I did run my 4 ohm LSi9's at the same time as my 8ohm CSiA6 and Fxi's from my XPA-5, to do some comparisons and it worked fine. It may be fine, but I really don't know for sure.

bluecomet

For my HT, I also have a LSI center. I am running a Yamaha RX-V2300 6.1 system. I turned my receiver to 6 ohms and it seems to be running the LSIC fine. My mains are RT800i's, rears F/X 30i's and rear center is C400i. I too got a good deal on the LSIC and did not know until I opened the box it was 4 ohm. I use this system for mostly movies and it seems to work well but I am wondering if I should change out the LSIC to another 8 ohm speaker. In my system when I turn up the volume the LSIC shines probably because it is getting more power.

seeclear

mmadden28 wrote: »

I'm pretty sure you shouldn't be mixing 4 and 8 ohm speakers on the same amp/avr.

It doesn't sound like he is, is he? It looks like he is running all the 8 ohm speakers off the receiver, then the center lsi 4 ohm'r is coming off the pre-out to an external amp. I don't see why that would be a problem unless the amp is not 4 ohm stable, but the parasound should be fine with that.

Timber-matching? Yeah, great if you can, but I don't notice a difference with non--matched speakers, and a lot of people won't.:eek: If it sounds good, do it! I think your setup is fine the way it is.

seeclear

Oh, and another thing that I haven't seen addressed here--Why not go ahead and bridge the amp for the center? It won't make it necessarily any louder, after you calibrate, and it will give the center more headroom before clipping. The speaker will like more watts of headroom much more than too little, and the lsic can handle it.

mmadden28

seeclear wrote: »

It doesn't sound like he is, is he? It looks like he is running all the 8 ohm speakers off the receiver, then the center lsi 4 ohm'r is coming off the pre-out to an external amp. I don't see why that would be a problem unless the amp is not 4 ohm stable, but the parasound should be fine with that.
...

I was addressing this question (not what he was doing):

SiddPolk wrote: »

..... so it doesn't sound like a good thing for the onk to mix in a 4 ohm. Anybody know about this?
...

and also note the subject of the thread

Eric W

First, provided the amplifier is stable into the load trying to be driven, it doesn't matter if you "mix" impedances on a single receiver or amplifier. I'd be far more concerned about the tonal match instead of the electrical match.

I wouldn't bridge mono an amp into the LSiC. It's a 4 ohm speaker and not many amps can take a bridged 4 ohm load. Even if they could that would be running on the edge (the speaker does dip below 4 ohms) of the amp's current capability. I'd much rather bi-amp the center by leaving the amp in stereo mode.

SiddPolk

seeclear wrote: »

It doesn't sound like he is, is he? It looks like he is running all the 8 ohm speakers off the receiver, then the center lsi 4 ohm'r is coming off the pre-out to an external amp. I don't see why that would be a problem unless the amp is not 4 ohm stable, but the parasound should be fine with that.

Timber-matching? Yeah, great if you can, but I don't notice a difference with non--matched speakers, and a lot of people won't.:eek: If it sounds good, do it! I think your setup is fine the way it is.

Thanks for the reply, and your right ... I'm not currently mixing the 4 and 8 ohm speakers on the same amp. The 8's are on the Onk and the 4 is on a single channel of the Parasound. I have now noticed the timbre matching issue with the LSiC vs. the RTs. When watching TV or even a non action movie, the LSiC sounds great, however when things get 'involved' and an object travels from left through center to right, you can hear a suttle difference where I know there shouldn't be. So the LSiC will be up for sale and a CSi5 is on the way.

SiddPolk

seeclear wrote: »

Oh, and another thing that I haven't seen addressed here--Why not go ahead and bridge the amp for the center? It won't make it necessarily any louder, after you calibrate, and it will give the center more headroom before clipping. The speaker will like more watts of headroom much more than too little, and the lsic can handle it.

This was my first thought too, until I checked the bridged mono output of the Parasound, it's 600w at 4 ohm. Kinda scared me a little to have that much available to the LSiC. I'm not worried about the Parasound, but I am a little worried about the LSiC with my 13 year old while daddy's not home (I remember me at that age).