It shouldn't have made a difference but it did...

[mpompey]

I've been upgrading my speakers in my home theatre. I've replaced the rears and centers with speakers from Axiom. The only speakers that are 8 ohms are my presence effect speakers, everything else is 6 ohms. On a lark, as I was calibrating the new center, I decided to change the receiver from 8 ohm minimum to 6 ohm minimum.

I switched the minimum impedance on my RX-V1500 receiver to 6ohms from 8ohms. And the sound quality was significantly better. I'm talking night and day difference. So much so that my wife who isn't an HT A/V junkie noted the difference. One example is during the final fight scene in Revenge of the Sith, when Vader and Kenobi take shelter during one of the lava eruptions. It always sounded good, but now it literally sounds like the lave debris is in the room with you, falling all around you.

But from everything I've read this shouldn't be the case. Switching from 8ohm minimum to 6 ohm, should have made the sound less dynamic, with less voltage going to the rails, correct? But if that is the case why does it sound so much better.

 

[Seth=L]

So much so that my wife who isn't an HT A/V junkie noted the difference.

This is the best line ever.

It is interesting to hear about it making a difference. My JVC has an Ohm selector switch for 8-6 ohms and 4 ohms. I will have to check and see if it makes a difference if I change it.

 

[jcPanny]

Speaker calibration

MP,
Is it possible that the speaker recalibration and the new Axiom speakers made a big difference and not the switch from the 8 ohm to the 6 ohm setting on the receiver? Like you sugested, the 6 ohm setting only limits the power delivered by the receiver for electrical certification purposes.

 

[mpompey]

The area of most improvement has been in the area of the surrounds. I had the QS8s installed before getting the 150. Prior to making the switch, the surrounds felt subdued. Plus when doing the calibration I don't remember adjust the levels of the surrounds.

Unless on my receiver, the 8 to 6 ohm circuit is reversed. Hey, I'm not touching it! Whatever the explanation, it sounds better than ever before.

 

[agarwalro]

Here's a thread that discusses the differece in the 6 ohm and 8 ohm settings.
http://forums.audioholics.com/forums/showthread.php?t=10519

You are best off leaving the setting at 8 ohm.

 

[no. 5]

The 4 ohm setting limits the amount of power output (the 8 ohm setting does not), so with the limitation removed, it is quite believable that it would sound better.

 

[PENG]

But from everything I've read this shouldn't be the case. Switching from 8ohm minimum to 6 ohm, should have made the sound less dynamic, with less voltage going to the rails, correct? But if that is the case why does it sound so much better.

You are correct, and the fact that you heard much better sound defies logic and electrical theory. May be your RX-V has some bad connections in the 8 ohm position, or something else is wrong. It could also be that in this particular specimen, the 8 ohm taps are connected to the selector's 6 ohms position and vice versa. You may want to use a SPL meter and a test tone to verify that you are in fact getting higher SPL in the 8 ohm position with the volume in a same fixed position for either 6 or 8 ohm positions. If not, it would again, suggest that there is a wiring error.

 

[no. 5]

This may shed some light on it (the editorial note under "Chousing Speaker Impedance").

 

[PENG]

This may shed some light on it (the editorial note under "Chousing Speaker Impedance").

Did you read his question carefully? He knows he should have got better sound with the switch in the 8 ohm position, but he is getting it in the 6 ohm position instead.

 

[Davemcc]

Forgive me if I'm being simple, but it's easy to switch, right? Why not point out to your wife how to switch it, then have her switch it back and forth while you listen. Make it a blind test so you know the results are that which sounds best, if there is a difference at all.

 

[no. 5]

Did you read his question carefully? He knows he should have got better sound with the switch in the 8 ohm position, but he is getting it in the 6 ohm position instead.

Hmmm.... apparently not. I apologize for my presumptuousness.

 

[PENG]

no. 5, I just wanted to make sure you know what he was saying so that you may come up with some good ideas/suggestions that can explain what he is experiencing.

 

[mtrycrafts]

This is the best line ever.

I don't know about that. How could it compete with wife able to telling a difference driving up the driveway

 

[mtrycrafts]

Did you read his question carefully? He knows he should have got better sound with the switch in the 8 ohm position, but he is getting it in the 6 ohm position instead.

It seems that he did multiple changes taking time and fading memory not to mention bias. Short of a real problem with the receiver or setup, I would favor the time and bias aspect and lack of careful comparison.

 

[no. 5]

no. 5, I just wanted to make sure you know what he was saying so that you may come up with some good ideas/suggestions that can explain what he is experiencing.

Well thanks PENG . After (carefully) re-reading the OP.... it may be that the sound is perceptually "better"; if the 6 ohm position is limiting the output, then it may be lightly clipping and causing the surrounds to sound brighter, and possibly better sounding to your ears.

But definitely try what Davemcc suggested.

 

[mpompey]

You know I may try that blind test thing this weekend as well as the SPL meter.

That will tell the tale.

 

[mpompey]

I think I figured it out. YPAO is the culprit

I tried the blind test this morning and could not determine any significant difference with my ears. I didn't have time to set up my SPL meter. Then it dawned on me...

I'm not going to be able to resurrect the initial conditions, because I re-ran YPAO EQ when I installed the new center. The surrounds had to have been re-EQ'ed to match the front. With the new center, the front soundstage changed, so the receiver had to have changed the PEQ settings for the surrounds. But since I never wrote down the previous EQ settings I'll never know for sure.

 

[no. 5]

...I re-ran YPAO EQ when I installed the new center.

Well if you had told us that...

 

[mpompey]

It didn't come to me until I was doing the blind test. But now I'm not so sure YPAO is the culprit here. As the FRONT setting on YPAO is supposed to match everything to the Front L and R speakers which did not change. Oh well, as the blind test didn't distinguish any difference between the two setting.

Maybe I'm going crazy.

 

[Ampdog]

No Mpompey,

You are not going crazy. Realise that hearing is a b..... Also, as Peng said, something is wrong here. Looking at the quoted Yamaha note, they give 144W for the 8 ohm setting and 78W for 6 ohms.That is almost 3 dB but 8/6 ohm is only 2.5 dB. Not a great difference, until one calculates that with 144W for 8 ohms, exact reduction should have given 108W and not 78W - now it seems somewhat more enigmatic.

Fine, you mentioned that other changes occurred, so the matter is explained. I simply wanted to indicate that nothing mentioned here would even have been audible to most people at 2,5 dB difference.