Subwoofer 2.2 vs. 2.1 REW measurements

[dallasjustice]

That's a single sweep correction. I don't trust multi seat music listening since I don't understand how the time domain can be optimized from multiple seats. I'm very happy with the music in my room!

I agree Acourate is more flexible and I plan to crack it open again. AL is great because I can get really sweet filters very fast. I can try out various setups and create zones in Jriver in just a few minutes. I don't need to worry about cfg files. I am a happy owner of both.

I bet your system sounds great. Have you tried rolling off the bass below 20hz? I have been having some interesting email exchanges with Mitch Barnett about rumble filters.

do you do a single seat measurement in audiolense or multiseat?

I use acourate & have been playing with trying to correct the phase response of a passive speaker recently. The thing I like about acourate is the seemingly bottomless pit of things to experiment with (albeit if you know how to experiment with it). FWIW my current response is as follows, my room is untreated (except for normal furnishing) hence the somewhat wriggly mid range.

View attachment 19128

 

[dallasjustice]

I tried to set up a loopback for the time reference. It's not going to work in this setup. The reason is that subs are 2.2 mono so that the signal will get sent to both subs, no matter right or left channel. My time reference must pass through my convolution filter to be accurate, since most of the delay is from the filter. If I send the time reference through the unused left or right channel, the time reference signal ends ups adding to the log sweep on both subs. I can't think of a way around it. It's not that important anyway, since I don't need to measure in absolute time.

that sounds like it should work yes. Note that the only limitation is that the timing is based on the impulse peaks so if you try to match a low pass against a high pass then you'll just get fail as your end product

to give a concrete example, I run a 5.1 setup where

output 1-6 = physical outputs
output 7 = REW signal output channel
output 7-8 = jriver asio line in
output 12 = set to copy one of the jriver output channels and looped back to input 12
input 12 = REW timing reference

 

[3ll3d00d]

I tried to set up a loopback for the time reference. It's not going to work in this setup. The reason is that subs are 2.2 mono so that the signal will get sent to both subs, no matter right or left channel. My time reference must pass through my convolution filter to be accurate, since most of the delay is from the filter. If I send the time reference through the unused left or right channel, the time reference signal ends ups adding to the log sweep on both subs. I can't think of a way around it. It's not that important anyway, since I don't need to measure in absolute time.

remember that once you have such measurements then you can accurately sum them after the fact (i.e. use trace arithmetic in REW) which means you are normally measuring one channel (which could be multiple subs but still) at a time. The convolution problem can be dealt with by simply routing the channel you intend to loopback through the filter as well, e.g. in jriver just use mix channels to copy the channel you're measuring to another unused channel and don't route that to a physical speaker.

 

[dallasjustice]

remember that once you have such measurements then you can accurately sum them after the fact (i.e. use trace arithmetic in REW) which means you are normally measuring one channel (which could be multiple subs but still) at a time. The convolution problem can be dealt with by simply routing the channel you intend to loopback through the filter as well, e.g. in jriver just use mix channels to copy the channel you're measuring to another unused channel and don't route that to a physical speaker.

Okay. So, I think you are saying I can use the Jriver room correction tab to copy a used channel to an unused channel. Then I can patch that unused channel in the Lynx back to the selected REW time reference input channel?

Also, if I use this strategy, does Jriver room correction tab happen before or after the convolution process? Would the order of events be shown in the Jriver audiopath? Does Jriver allow me to re-arrange the order of events so that the copied channel happens AFTER the convolution?

Thanks for all of your help!

Michael.

 

[3ll3d00d]

Yes that's right. JRiver has 2 Parametric Equaliser stages so you can drag one to execute before convolution, i.e. on the input (source) channels, and one to execute after convolution, i.e. on the output channels.

Audio path does show it yes, for example this shows my use of the 2 PEQ stages for bass management