Speaker Placement a Key to Imaging

[Robh3606]

Not so..., or at least the way I do it.

I use the RTA with the mic set at the sweet spot and simply move the mid-cabinet/Heil back and forth until I get the smoothest transition in the crossover areas.

Does this result in time alignment???

Probably pretty close..., and even if not, I know these to be the "smoothest" positions attainable (+ or -) in the room with the set-up. I know where the mid-cabinet and Heil currently sit so can easily put them back.

Hello Toddalin

What you are doing is making sure the drivers sum properly through the crossover. I used to do the same thing when I had my RTA. It finally gave up the ghost last year.

An RTA is not the right tool to judge time alignment you could be one or more cycles out of alignment and you won't see it.

Depending on spacing and crossover point's It could be in time alignment but more than likely, like most other speakers it is not.

With Gregs example using the Array to Time align them he would have to move the horn back on full wavelength @ 800 Hz. They sum properly because they are in phase at the crossover point but the woofer arrives behind the horn instead of with it because of the position of the upper horn cabinet.

Rob

[toddalin]

Hello Toddalin

What you are doing is making sure the drivers sum properly through the crossover. I used to do the same thing when I had my RTA. It finally gave up the ghost last year.

An RTA is not the right tool to judge time alignment you could be one or more cycles out of alignment and you won't see it.

Rob

Then you pose the delemma as to what is preferable..., the smoothest frequency response, or the best time alignment. But let me say that using my current technique, I've never heard speakers that image as well or throw as big a soundstage as the Mermans, so I can't be too far off. And I've heard Magicos, Focals, and Harbeths.

On further throught, I don't see how I could be one wavelength off. The crossover between the 2251J and Heil is ~2,500 Hz, so a wavelength would be ~5" long. The cabinet is only 8" deep and the center of the Heil would appear to be somewhere within the magnetic structure/heat sink fins of the 2251.

Similarly, the 2251 sits somewhere close to/within the magnetic structure area of the 2241. That crosses over at ~350Hz and is all done by less than 1kHz, so the wavelength would be over a foot long.

In either case, how could I be even one wavelength off?

[Robh3606]

Then you pose the delemma as to what is preferable..., the smoothest frequency response, or the best time alignment. But let me say that using my current technique, I've never heard speakers that image as well or throw as big a soundstage as the Mermans, so I can't be too far off. And I've heard Magicos, Focals, and Harbeths.

On further throught, I don't see how I could be one wavelength off. The crossover between the 2251J and Heil is ~2,500 Hz, so a wavelength would be ~5" long. The cabinet is only 8" deep and the center of the Heil would appear to be somewhere within the magnetic structure/heat sink fins of the 2251.

Similarly, the 2251 sits somewhere close to/within the magnetic structure area of the 2241. That crosses over at ~350Hz and is all done by less than 1kHz, so the wavelength would be over a foot long.

In either case, how could I be even one wavelength off?

Hello Toddalin

In my mind smoothest frequency response. I don't worry about time alignment. None of my systems I own or ever have owned have been TA with the exception of My 811C clone I used as a center. That's the only stand out.

You also have your crossover in the mix not just physical spacing both vertical and horizontal.

But time alignment is not critical. It's the exception and not the rule.

I would just do what you have been doing. I am guessing you are using the sweet spot as your microphone position and setting them up that way or 1 meter both? I would do 1 meter and sweet spot. Microphone placement will change things.

That's how I did mine back in day before I had a measurement set-up. Your happy with your results so that's what matters.

Rob

[toddalin]

Hello Toddalin

In my mind smoothest frequency response. I don't worry about time alignment. None of my systems I own or ever have owned have been TA with the exception of My 811C clone I used as a center. That's the only stand out.

You also have your crossover in the mix not just physical spacing both vertical and horizontal.

But time alignment is not critical. It's the exception and not the rule.

I would just do what you have been doing. I am guessing you are using the sweet spot as your microphone position and setting them up that way or 1 meter both? I would do 1 meter and sweet spot. Microphone placement will change things.

That's how I did mine back in day before I had a measurement set-up. Your happy with your results so that's what matters.

Rob

Mic in the sweet spot. I don't listen at 1 meter and it is really too close for proper integration of the various components.

[Mr. Widget]

Mic in the sweet spot. I don't listen at 1 meter and it is really too close for proper integration of the various components.

I think the point Rob is making and I agree with him, is that your system is most likely not actually time aligned, but it doesn't matter since it works well and pleases you.

Very few systems are truly time aligned and it is very difficult to achieve even with very precise and careful digital correction.

FWIW: If you want to find out if it is time aligned ask someone to come over with software and a mic that can measure your impulse response using either FFT or MLS measurement techniques.


Widget

[Robh3606]

Mic in the sweet spot. I don't listen at 1 meter and it is really too close for proper integration of the various components.

Hello Toddalin

The point isn't to listen there? You get a good look at the integration of the mid and tweeter on the design axis.

When you measure at the sweet spot you typically are off the design axis and you see how much HF loss you have with distance and with mine slightly below the design axis.

I like to have both points.

Hello Widget

Yep that's about it.

Rob

[toddalin]

My speakers are 7.5 feet center to center. The panned Rhodes spans beyond the full 26 feet of the room, even with eyes open.

https://youtu.be/tvaGNfk3Ipg

[Robh3606]

My speakers are 7.5 feet center to center. The panned Rhodes spans beyond the full 26 feet of the room, even with eyes open.

https://youtu.be/tvaGNfk3Ipg

OK so is this with changes? Have you changed anything or just going with smoothest FR response like your prior set-up?

Rob

[toddalin]

OK so is this with changes? Have you changed anything or just going with smoothest FR response like your prior set-up?

Rob

Smooth response, but really no changes here. The track is not from my stereo. The camera mic would never capture that much localization in the room for subsequent publication on YouTube.

The post is to show what is attainable with good imaging and the Rhodes on this track provides a really wide image. I've never been able to get to this level with the L200/300s, or anything else for that matter.

Does the Rhodes fill the entire "front of the house" or does it stay pretty much between/just beyond the speakers on other people's systems?

[Robh3606]

Hello Toddalin

That's a wild effect! It goes across the front wall well beyond the speakers almost like it's wrapping around. Tried it on 2 systems off the CD my M2's so 15 and 4" CD and F206's cones and domes. Better on the M2 probably because of set-up.

Reminds me of Q Sound. If you have not all ready try Roger Waters Amused to Death, lots of wild stuff, fun listen.

Rob

[rusty jefferson]

Well, it's a multi-track studio recording to start with, and according to some people on the interwebs (take that for what it's worth) it's either a Korg, or a Rhodes that's using a phase shifting effects pedal. I'm not near a stereo to listen to it, but if its got phase shifts it isn't a good track to show how well your system recreates a natural soundstage. I imagine it was made to sound cool to folks who may have altered their consciousness just prior to dropping the needle. :-)

[Robh3606]

Well, it's a multi-track studio recording to start with, and according to some people on the interwebs (take that for what it's worth) it's either a Korg, or a Rhodes that's using a phase shifting effects pedal. I'm not near a stereo to listen to it, but if its got phase shifts it isn't a good track to show how well your system recreates a natural soundstage. I imagine it was made to sound cool to folks who may have altered their consciousness just prior to dropping the needle. :-)

Hello Rusty

Ever listen to the Q Sound material? It's manipulated for sure but still a fun listen. That's what it sounds like almost out of phase as the song continues the effect is turned off and it collapses into the middle of the speakers.

Rob

[rusty jefferson]

Hey Rob, yes I'm familiar with the Roger Waters recording you mentioned. That's the only Q Sound I'm aware of hearing.

On a favorite Joni Mitchell recording, Blue Motel Room they put the guitar out of phase and hence way outside the speaker boundaries. Not the same as having a big soundstage. :-)

[Mr. Widget]

Does the Rhodes fill the entire "front of the house" or does it stay pretty much between/just beyond the speakers on other people's systems?

Waaaaay beyond.

I just played the Sheep track on two systems. My Project Widgets and my HT Meyer Sound Ultra-X20s. I haven't bothered to verify if the Meyers are time aligned, but they probably are since the geometry and DSP make it pretty easy to do. My Project Widgets are totally old school like a 43XX... different arrival times for the different drivers (and it's a 4-way)

Both systems created a nicely 3D soundstage for the sheep and birds with the piano extending far off to the left and right of the speakers. For this track at least, time alignment doesn't seem to be necessary.

Rob, I agree it does seem to almost wrap around. I've heard that effect on a couple of other stereo recordings where they seem almost surround sound.


Widget

[toddalin]

The stereo panning effect was actually built right into the later Rhodes without the need for external equipment other than a stereo amp and speakers to really take advantage of it.