Mixing 4 ohm and 8 ohm speakers in a HT system

helipilotdoug

OK, here is what I've got.
Receiver: Pioneer VSX-84TXSi
Mains: Polk SDA 2B 4 ohm
Center: Polk CSia6 8 ohm
Sides: Polk FXi A4 8 ohm
Rear: Polk FXi A6 8 ohm
Sub.: Polk DSW MicroPro 1000 (being fed by pre amp.)

I have a set of SDA 2B speakers, that I bought in 1987, and they are still in use. I love my good old SDA 2's, and really do not want to replace them.

My questions are:
1. The receiver only has settings for 6 ohm and 8 ohm speakers. But you can only set the receiver ohm setting for all speakers, not individual speakers, like fronts, center, etc. I'm thinking it might be best to set the system to 6 ohms with this setup. What do you think?

2. From what I've read, 4 ohm speakers will usually put out 3 db more than 8 ohm speakers, at the same power input level. So should I set my 8 ohm speakers to + 3 db in the setup menu?

3. This receiver does not offer a 4 ohm setting. Are there any problems I can expect to encounter using this setup?

Thanks in advance for your help.

ViperZ

Set your receiver to 6-Ohm load. Putting 8-Ohm speakers won't hurt that.

I found that the mix of 4-ohm and 8-ohm speakers did not work for me at all. I tried using 4-ohm Totem speakers in the back while using B&W 8-ohm speakers in the front. Totem were harder to drive and I had to run higher volume overall.

Knucklehead

Overheating and possibly damage to your AVR and or speakers. If your AVR has preouts, buy a 4ohm stable amp and you should be good to go. David

McLoki

Even a 2 channel amp you can just run your fronts off of would be fine. (you can continue to run the rest of your speakers from your AVR.) The cost for a decent used 2 channel amp should be fairly decent anyway.

Michael

thuffman03

Would not suggest a 4ohm speaker on an AVR. Very few do well with that low of impedance.

Get a seperate 2 channel amp for the SDA's.

McLoki

Forgot to mention with SDA's - make sure any amp you get is common ground.

helipilotdoug

Hmmmmm. Well, now I'm kind of uncertain as to what to do. I've been using these speakers for years on a Proton D 1200 amp. After we up-graded to the 7.1 system I sold the amp. Now I'm kind of wishing I had not! I'm not really wanting to add another amp. to my system. Even though I'd rather keep my SDA's I'm seriously debating whether to maybe up-grade my mains to another set of newer speakers. Polkdirect has some LSi 25 speakers for about half the cost of new right now. If I'm going to replace my mains, I'd like to get the best Polk has to offer, and from what I've seen, the LSi 25's are the best. of course I could get rid of my sub with these speakers, and use the built in subs. Give me your thoughts on replacing my SDA's with these.

wutadumsn23

Even if you decided to go with the LSi 25's, you would need an external amp to power them to their potential as they too are 4 ohm speakers. Using an AVR alone is not a good idea with 4 ohm speakers, because they will occasinally drop down even lower in the ohm department and it will eventually cause your AVR to go into protect mode, or you will damage the speakers. You can somewhat prevent that with the 25's if you chose to run them off an AVR by being very careful with the volume knob, but lets face it, who is going to buy a speaker like the LSi 25's and not want to show them off? IMHO, the SDA's beat out the 25's, but the 25's are Polks current flagship model and from what I have "heard" are worth every penny. Looks like you will have to try and get your ears on them to decide. Also keep in mind that if you do make the switch to the LSi line, you will need to get, at the very minimum, a new center. The LSiC is the one you want. Getting an external amp for the SDA's would def. be a cheaper option as all you would need is the amp. Just my $.02.

-Jeff

helipilotdoug

Thanks Jeff. I did not know the LSi 25's were also 4 ohm speakers. Sounds like I'd be in the same situation and it would be pointless to spend the money on them, and still have to get another amp. to power them. OK, how about the RTi A9 speakers. Are they 8 ohm speakers? I have not been able to find the ohm specs posted anywhere, but I'm sure there is a place to find them somewhere. Also, I'm thinking the RTi A9 speakers would fit in with the rest of my speakers perfectly, since they are RTi series. Thoughts?

Edit: Found the specs on the RTi A9 speakers and they are 8 ohm.

wutadumsn23

Yes, the RTi A series are 8 ohm speakers. They will operate off an AVR, but again to run them to their potential, you would need an amp, lol. They operate at 50-500W, so they can be power hogs. An amp is not a must, like with the SDA's or the LSi's, but it would def. bring them to life. Since you already have the CSi A6, you are golden there. Hope this helps.

-Jeff

helipilotdoug

Thanks again Jeff. I'm going to seriously consider the RTi A9's. Now if I can find a good deal on them, it will help me make up my mind! My receiver puts out 145 watts per channel, and I'm thinking that will be enough for now. I really don't want to get another amp. This receiver replaced 3 other pieces of equipment (pre amp, power amp, and tuner), and I finally have the "stack" cut down to size.

nooshinjohn

I do this in my rig, with SDA SRS 2.3TL's up front and LSi-15's as surrounds and a CSiA6 center channel. The catch is that everything runs on separate amps, and it works very well for my needs. I am increasing the power to the center/surrounds this week.

wutadumsn23

helipilotdoug wrote: »

Thanks again Jeff. I'm going to seriously consider the RTi A9's. Now if I can find a good deal on them, it will help me make up my mind! My receiver puts out 145 watts per channel, and I'm thinking that will be enough for now. I really don't want to get another amp. This receiver replaced 3 other pieces of equipment (pre amp, power amp, and tuner), and I finally have the "stack" cut down to size.

Keep in mind that most AVR's are rated when operating only two channels and some are rated at only one. Those numbers are not accurate with a 5 or 7 channel system, and they will shrink quickly the more speakers you add to the mix. Unless it uses seperate mono block amps for each channel, which is pretty rare.


-Jeff

helipilotdoug

Hmmm again OK I had the power wrong. It's really 140 watts per channel. I checked the owners manual, and came up with this (I have the 84TXSi):
Specifications
Amplifier section
Continuous average power output of 140 (or 130)
watts* per channel, min., at 8 ohms, from 20 Hz to
20 000 Hz with no more than 0.09 %** total harmonic
distortion (front).
Continuous Power Output
(20 Hz to 20 kHz, 8
Ω
, 0.09 %)
Front. . . . 130 W + 130 W (82TXS), 140 W + 140 W (84TXSi)
Center . . . . . . . . . . . . . . . . . . 130 W (82TXS), 140 W (84TXSi)
Surround . . . . . . . . . . . . . . . . . . . . . . 130 W + 130 W (82TXS)
140 W + 140 W (84TXSi)
Surround back . . . . . . . . . . . . . . . . . 130 W + 130 W (82TXS)
140 W + 140 W (84TXSi)

Also here is a link to the specs on the pioneer website.
http://www.pioneerelectronics.com/PUSA/Products/HomeEntertainment/AV-Receivers/EliteReceivers/VSX-84TXSi?tab=B
From what I see, it's saying this truly is 140 wats per channel. Is that right?

nooshinjohn

...don't believe everything you read in the manual. Pioneer builds great gear, but trust everyone on this. Each channel is capable of 140wpc, BUT with all channels placing demands on the same reservoir of power, the output will be lower than the stated claim. Your specs even allude to this by claiming "Continuous AVERAGE Output"....

helipilotdoug

OK, Thanks for the education. I have a feeling the only way to tell what I'll have is to find a store that has a similar setup to mine, (140 wpc) with the RTi A9and other speakers, and see how it sounds. This is becoming a lot more difficult than I thought when I started this thread. Every way I turn seems like I'll have to spend more money!! LOL Don'cha hate when that happens!! Anyway, I'll have to do some rethinking on this. Thanks for all the input.

nooshinjohn

welcome to the world of audio...

wutadumsn23

nooshinjohn wrote: »

...don't believe everything you read in the manual. Pioneer builds great gear, but trust everyone on this. Each channel is capable of 140wpc, BUT with all channels placing demands on the same reservoir of power, the output will be lower than the stated claim. Your specs even allude to this by claiming "Continuous AVERAGE Output"....

+1, while that AVR looks rather beastly, I still doubt that it will be pushing 140W at all times to all channels. Most of the power ratings I have seen on that model are listed at 2 channels running. The number will drop off a bit with more channels being operated.

-Jeff

helipilotdoug

OK, my rethinking is this. Stay with my SDA 2b's and get a power amp that is rated for 4 ohm (but also 8 ohm) to power them. Power the center and surrounds with the Pioneer 84 TXSi. Later on if I decide to change out my mains, I'll have a power amp in place. New questions are:

1. What COMON GROUND power amp recommendations (make, power output etc.) do you have for this purpose, that will also work well for future main speaker replacement?

2. How will this perform, with the SDA 2b's, both in HT and 2 channel music?

Thanks

Paden501

helipilotdoug wrote: »

OK, my rethinking is this. Stay with my SDA 2b's and get a power amp that is rated for 4 ohm (but also 8 ohm) to power them. Power the center and surrounds with the Pioneer 84 TXSi. Later on if I decide to change out my mains, I'll have a power amp in place. New questions are:

1. What COMMON GROUND power amp recommendations (make, power output etc.) do you have for this purpose, that will also work well for future main speaker replacement?

2. How will this perform, with the SDA 2b's, both in HT and 2 channel music?

Thanks

This is exactly how mine is set up w/ my 1Cs. I have an Onkyo TX-DS777 home theater receiver running my surrounds and a Carver TFM-24 powering the SDAs up front. It works well.

helipilotdoug

What do you all think about the Carver TFM-45 amp? It's a little more powerful, but seems like it would be good for use with the SDA 2B's as well as with any future speakers I might decide to purchase. How much should I pay? Comments on this amp?

helipilotdoug

Just recently I got a Carver TFM-45 and a C-11. Here is my dilemma. When listening to the HT I'm running the main speakers from the TFM-45, which is hooked up to the pre outs on the Pioneer. This seems to be working very well. However when I listen to music and switch to stereo, I'm not near as pleased with the performance of the pioneer as a pre amp, as I am with the Carver C-11 preamp. What I'd like to do is Use the before mentioned setup for HT, but have the capability of feeding music through the Carver pre amp, without having to switch wires around all the time. What do I need to do to be able to feed both pre amps into one amp without having to switch wires? Is there a switcher of some type that I can get that will allow me to do this, or can it be done without a switcher? Thanks for any help on this.