LCR subwoofers with center subwoofer playing out of phase sounds?

[Oddball]

Any measurements that you could share? Otherwise, not sure where your journey took you.

 

[olds1959special]

Any measurements that you could share? Otherwise, not sure where your journey took you.

I used the RTA in REW with ECM8000 mic and cal file, and on my phone (to double check). The mic was on a stand in the listening position. I found after doing some initial measurements I needed to adjust the speakers/subs a little, so I turned down the LPF on all three subs to 80 Hz, to match the HPF of the front speakers. I also turned down the low trim on the main speakers a notch. Then I found I needed to apply a subtractive EQ of 4 dB at 86 Hz (probably my room.) Here are the screenshots of the measurements I took.

full range pink noise:

full range pink noise, with second output inverted so that it will also play on the rear speakers.

 

[DVDdoug]

There is nothing odd about what I'm doing,

How many other people are dong this? Probably one out of 1000. I'd say that's "odd". And some (most?) AVRs have matrix decoding and better ways of up-mixing so that's a more common way of doing it.

It was "odd" when I was doing it in the 1970s. I couldn't afford "quad" and I didn't have any quad recordings but I built a subtraction amplifier and I had an extra pair of speakers. I had fun with it. Then I went back to regular stereo for a few decades. I never had Pro Logic but I eventually got Dolby Digital Surround with a DVD player and AVR.

 

[olds1959special]

How many other people are dong this? Probably one out of 1000. I'd say that's "odd". And some (most?) AVRs have matrix decoding and better ways of up-mixing so that's a more common way of doing it.

It was "odd" when I was doing it in the 1970s. I couldn't afford "quad" and I didn't have any quad recordings but I built a subtraction amplifier and I had an extra pair of speakers. I had fun with it. Then I went back to regular stereo for a few decades. I never had Pro Logic but I eventually got Dolby Digital Surround with a DVD player and AVR.

I don't own an AVR, and they are so bulky.

 

[Chrispy]

There is nothing odd about what I'm doing, I don't think and to me it sounds great. It's a new way to hear stereo recordings.

I'm not running the subs full-range anymore. That idea started with the miniDSP where I could add the crossover myself, but in this setup the subs are coming from the same channels the mains are, so I can't do that.

Stereo subwoofers is not a new idea and some people like it. LCR subwoofers is not much different, and it works for me because the center sub doesn't have to match. The center sub is like a mono fill channel for the bass and seems to add a little more homogeneity to the lows.

Yes there is, but good luck!

 

[olds1959special]

Yes there is, but good luck!

If I had an AVR and surround setup and upmixed the stereo it would be more or less the same, but this is what I have.

 

[Chrispy]

If it sounds good, it is good! If I had an AVR and surround setup and upmixed the stereo it would be more or less the same, but this is what I have.

Maybe. The dsp on avrs is probably better than what you're doing, though. An avr is perhaps on the large side, but not much different than my 2ch receivers in the 70s....and IME the avrs are far better than those receivers. Let alone the bulk of a '59 Old Special!

 

[olds1959special]

Let alone the bulk of a '59 Old Special!

Well it’s just a cornet. You can play it with one hand!

 

[Chrispy]

Well it’s just a cornet. You can play it with one hand!View attachment 485815

LOL guess I was thinking of a Buick in any case

 

[sam_adams]

LOL guess I was thinking of a Buick in any case

The Buick Special model was absent from the Buick lineup in 1959 and 1960. It returned in 1961 with a completely new body style. There never was a 'Special' model in the Oldsmobile line.

 

[olds1959special]

I'm not sure why, but I felt like disabling all EQ tonight, and turning the low trim back to 0 on the mains. I disabled the EQ on my other system too. I guess the small changes the EQ makes are not really as important as just letting the actual physical drivers/etc. do their work? Not sure, but I felt like I was getting the fullest sound without EQ. My acoustic situation in both of my setups is not bad though, and I'm not doing silly stuff like running my subs full-range anymore.

 

[Oddball]

I used the RTA in REW with ECM8000 mic and cal file, and on my phone (to double check). The mic was on a stand in the listening position. I found after doing some initial measurements I needed to adjust the speakers/subs a little, so I turned down the LPF on all three subs to 80 Hz, to match the HPF of the front speakers. I also turned down the low trim on the main speakers a notch. Then I found I needed to apply a subtractive EQ of 4 dB at 86 Hz (probably my room.) Here are the screenshots of the measurements I took.

full range pink noise:

View attachment 485759
View attachment 485757

full range pink noise, with second output inverted so that it will also play on the rear speakers.

View attachment 485760
View attachment 485758

Well, it is what it is. AVRs are really good nowadays and some of them have advanced room correction that could help you achieve more with the gear your have.

 

[olds1959special]

There really isn't much bass in the rear signal anyway, and a host of problems created by arbitrarily swapping polarity on one of three subs. You would be better off calibrating all the subs with the front channels.

Did you read the article that someone posted in your other thread, about the guy with the Dunleavys in a Hafler rig? He seemed overly focused on the rears being extended or full range. I personally don't buy that. You have the equipment on hand to calibrate one of your subs to the rear speakers, so give it a whirl if you want (it would take more than merely flipping a phase switch), but I doubt it's worth the hassle.

I decided to experiment with the rears being more full-range too, so I picked up a KRK S10 (V2) subwoofer and plugged in the left rear output into it (plugging in both inputs causes the signal to cancel itself out!) I think it should be in phase with the rear speakers, so it's set to 0 phase. I'm listening to this recording now and sensing a fullness in the bass in the room that was not quite as enveloping before.

 

[olds1959special]

The last step to this seemed to be adding a center speaker. I placed a single Yamaha MSP5 on top of my center subwoofer under the desk. The reason I needed this is because I liked the rear channels turned up and was losing the vocals because they were being drowned out by the ambience recovery channel coming from the rears. Now I guess I have pseudo 5.1?

 

[Keith_W]

I do not think that putting a speaker under a desk like that is a good idea.

 

[olds1959special]

I do not think that putting a speaker under a desk like that is a good idea.

I think it’s not the worst thing since the volume is relatively lower than the mains. I don’t have a better place to put a center speaker.

 

[olds1959special]

I do not think that putting a speaker under a desk like that is a good idea.

You’re right after all so I’m trying it as a third rear speaker. I guess I'll have to turn the rears down though.

 

[olds1959special]

The center rear speaker wasn't helping so I got rid of that but in the process found I liked elevating my rear subwoofer by 15".

 

[olds1959special]

I do not think that putting a speaker under a desk like that is a good idea.

I moved it to the top of the desk. I just put my apps into little windows that float around the speaker.

 

[olds1959special]

I do not think that putting a speaker under a desk like that is a good idea.

This is working very well and doesn't block the screen!