New Amp

Seb

Hey guy's, new to this forum.

I have a set of SDA 1's and SDA 1a's. The amp makes mentions not to do below 4 ohms in Stereo. If I put boths sets of speakers in parallel, will they be at 4 ohms or lower. I thought I read somewhere here that the SDA's are 6 ohm speakers.

I guess I could always put them in series, I think that would make it 12 ohms if they are truely 6 ohms.

Anyway, please let me know what you think.

Thanks.

Face

I believe the earlier SDA's are 4ohm.

Do yourself a favor and only play 1 pair at a time.

danz1906

Face wrote: »

I believe the earlier SDA's are 4ohm.

Do yourself a favor and only play 1 pair at a time.

With 4ohms speakers dont run in series.

mhardy6647

I think you mean "in parallel".
Impedances in series are additive (two 4 ohm devices in series present an 8 ohm load).

joko38

I hope you can finish answering these questions:

Do yourself a favor and only play 1 pair at a time. Why? I've already played them together and they amazing. My room is very spacious and these thing fill it very well.

Are the speakers really 4 ohm? And does that mean that I can put them in Series to make 8 Ohms? Will this affect the sound.

Thank you for you assistance and time.

mhardy6647

Speaker impedance ratings are always nominal. Impedance varies with frequency.
This example (http://sound.westhost.com/tsp.htm )mentions the nominal impedance for a woofer (single driver), but the generally-accepted technique for assessing nominal impedance (measured impedance in the 'valley' above the impedance peak at resonance; typically in the neighborhood of 100 to 200 Hz) is the same for a speaker system.

Playing them in series most likely will affect the sound, and not for the better :-(

joko38

Understood,

How about in parallel?

Sorry for my ignorance, if I had the answers I wouldn't be here.

Thanks again for your help.

mhardy6647

Impedance is the AC analog of the DC electrical quantity known as resistance. Both are measured in units of Ohms, and both obey Ohm's law. Let's denote impedance (or resistance) with the letter "R".

For resistances (or impedances) in series:

the total resistance, Rt = R1 + R2 + R3 + ...

For resistances (or impedances) in parallel:

1/Rt = 1/R1 + 1/R2 + 1/R3 + ...

(or Rt = 1/(1/R1 + 1/R2 + 1/R3 + ...)


for two 8 ohm loads in series:
Rt = 8 + 8 = 16 ohms


for two 8 ohm loads in parallel:
Rt = 1/(1/8 + 1/8) = 1/(1/4) = 4 ohms

:-)

If you're interested in this stuff and don't have a local guru to apprentice yourself to, you might want to take a look at the vintage and venerable US Navy "NEETS" training documents. These were written to teach fundamentals of electicity and electronics to Navy men ("men" in those days) who may have just fallen off the turnip truck from East Armpit. It's really pretty digestible and is also available on-line:
http://www.rarmy.com/coleman/neets/

Seb

Great explaination. So the speakers mentioned above are definitely 4 ohms each right?

Thank you for your help.

mhardy6647

I couldn't even guess :-) These Polk gurus will know, though!
Did you check http://www.polksda.com/

heiney9

Yes, they are 4 ohm nominal and they dip as low 2 ohms at some lower frequencies. The load (impedance) is not a linear measurement it constantantly varies with frequency. Do NOT hook these up in series as that will be too much load for your amp.

I suppose you could experiment in parallel but it's not recommended......as that's not how they were intended to be run. But they are your speakers in your listening environment so do what you want...............you won't get much support here condoning that arrangement.

H9

Seb

Alright guy's thanks again for you help. I'm definitely not going to hook them up in series or in parallel. Much appreciated and well understood.

Final questions

1) Would it be more advisable to run these speakers with separate amps?
2) Can these speakers co-exist in the same room at the same time?
3) What kind of setup would you recommend to allow them to co-exist?
4) I also have a set of Monitor 10's that I would like to add to the room if it is possible. What would you recommend? Would you recommend it using a separate amp for these as well?

Thanks.

mhardy6647

heiney9 wrote: »

Yes, they are 4 ohm nominal and they dip as low 2 ohms at some lower frequencies. The load (impedance) is not a linear measurement it constantantly varies with frequency. Do NOT hook these up in series as that will be too much load for your amp.

I suppose you could experiment in parallel but it's not recommended......as that's not how they were intended to be run. But they are your speakers in your listening environment so do what you want...............you won't get much support here condoning that arrangement.

H9

Sseries will double the resultant load impedance; parallel will halve it.
Hooking 'em in series will make for a more amp friendly load, but having the VC inductances (and/or inductance and capacitance of the crossover of the first speaker in the series pair) may make for pretty weird sound.

heiney9

That's what I meant.............and that's what I get for making a hasty post from work, thanks for the correction

H9

Systems

mhardy6647 wrote: »

Hooking 'em in series will make for a more amp friendly load, but having the VC inductances (and/or inductance and capacitance of the crossover of the first speaker in the series pair) may make for pretty weird sound.

Agreed,If the best SQ is the goal then avoid the series connection.

Seb

Bump on my last few questions.

Thanks guy's.

mhardy6647

heiney9 wrote: »

That's what I meant.............and that's what I get for making a hasty post from work, thanks for the correction

H9

I thought you just had me on Ignore...


:-)

mhardy6647

Seb wrote: »

Bump on my last few questions.

Thanks guy's.

EDIT: oops, I am a moron. You meant the 4 questions you asked in Post #12, didn't you? :-P
I can't really answer any of them. Others can and will.

heiney9

mhardy6647 wrote: »

I thought you just had me on Ignore...


:-)

Are you kidding??? Why would I put you on ignore? Sometimes (rarely) your large photo's of old gear might be a tad annoying...........but you're one of the good one's here.

Perhaps you have me confused with someone else . AndyGwis keeps calling me Troy . That's not my name-lol

H9

zingo

Your Polk speakers were designed to be run one pair at a time. If you need to fill your room with more sound and those speakers aren't cutting it, you may need to look at a different pair of speakers.

Plus, most SDAs are too big for a room, not too small. What size room do you have?

Seb

The room is about 15 by 22.

Thanks.

Face

How do you have them set up in the room?

They should be 3' from the side walls, a few inches to a foot from the rear wall, and zero toe in.

Are you using the SDA cable?

Seb

I have them setup at the smaller end of the room 15' x 22'. 2 speakers on the left and two on the right.
2 feet from the back wall, 1 foot from the side walls and inch's way from each other.
I am using the SDA cable for both sets.

I think they sound pretty good but will try to move them away from the side walls to about 3'.

The only problem with that is that they will then be closer together and more towards the middle of the room.

Should I have them along the 22' wall instead of the 15' wall? This way I would be able to spread them out more.

What do you think?

Thanks.

Marty913

I'm thinking that you are not going to get any kind of imaging or sound stage with overlapping SDA effects plus duplicate overlapping stereo images. A wall of sound, yes. Is there a particular reason behind all this or just curiosity?

Seb

It's actually not that bad sounding. I agree with you, definintely a wall of sound but the room is completely filled.

Well, the real reason behind all of this is that I wanted to pick up an amp to drive both of my speakers in parallel, but, because they are 4 ohm speakers the Polk guru's set me straight and saved me some down falls.

Anyway, we can call it quits for this thread. I have enough info for the time being. I'll play around with the room and see what sounds best. At the moment the way the speakers are, the don't sound too bad.

Talk to you guy's later and thank you for your help. Much appreciated.

Face

Seb wrote: »

Should I have them along the 22' wall instead of the 15' wall? This way I would be able to spread them out more.

Yes, moving them away from the corners and placing them in an equilateral triangle with your listening position will yield the best results. Closer to the rear wall will add bass but pulling them away from the rear wall will give better imaging and soundstage. As always, YMMV. Good luck and let us know how you make out.

Seb

Check the attatchment. I've changed the room around so that I'm sitting like you said in your picture above. Trianular to the speakers.
Everything sounds amazing now. I put the 1A's on the outside to ensure that I get the best possible imaging. The 1's I put in the middle front to provide support and some imaging but I'm not depending on them for much.

The Montor 10's at the back are set to half the volume as the ones in the front, just so that the room stays filled. They work well back there. I don't have them pointed directly at my head, instead I have them pointed towards my stereo system to avoid the sound getting to my head before the 1a's have had there chance to get there..

It's more than I could imaging they would sound. Wow.

In the picture I also make mention of the fact that I'm driving each set of speaker with it's own amp. All fronts are being driving by 150wpc, the monitor 10's are being driving by 100wpc.

Thank you so much to all. It was worth talking about.

Take care.