You don't use any bass management? Think we discussed that already but without bass management (routing all low frequency content to one channel) any room calibration becomes unreliable. Mixing engineers mix low frequency content to any channel they like, rendering your calibration useless because it relies on all low frequency sources playing the same signal.
Best, Markus
Markus
As I have told you before, my receiver does that. Not all do. My experince with recordings is that the LF is monon and equally blended in all channels. That makes the most sense and it is the most common. But the mixing engineer is always free to do something stupid.
That all doesn't change the fact that your calibration is unreliable even with that special kind of routing your receiver provides which is not supported by other receivers and probably never will be.
An audio engineer takes a helicopter sound and pans it wherever it needs to be. This results in low frequency content that is not equally distributed to all channels although the sound itself was mono. Even worse: the helicopter might fly over from back right to front left (I posted proof of that). That would bust your low frequency calibration.
Most studios have bass management implemented. I know that Mi Casa didn't have it in the past but now they have. That means they care even less about what is mixed to which channel because bass management routes low frequency content to a monophonic subwoofer channel anyway. Furthermore LFE channel frequency content over 80Hz (or whatever crossover frequency the studio uses) will never be heard in the mixing process but ends up in your set up.
You'd get broader and more reliable support for your calibration by using bass management with speakers set to small.
Best, Markus
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The surronds are set to small and with the Pioneer, All lows are routed to the subs in multichannel IN ADDITION to the speakers not set as small. So the only difference in what I have and what you suggest is that there are lows from the mains. The calibration issue that you talk about is a small one.
These facts remain:
1. Only certain receivers are capable of routing low frequency content from ALL speakers set to "large" to the subwoofer out. Even your Pioneer does not route low frequencies from the surrund channels to the subwoofer, only from L, C and R.
2. LFE content is not distributed back to all speakers (but it should because the calibration is based on that assumption)
3. Low frequency content that is mixed to only one of the channels is not distributed to all loudspeakers (but it should because the calibration is based on that assumption)
4. LFE content that was not audible in the mixing process (when mixed with bass management) will wrongly become audible
The solution to all these problems is simple (switch all speakers to small) and should work with your calibration solution. What I like about your approach is that your optimization includes the mains. That's where all other solutions like Audyssey fail.
Best, Markus
1. Only certain receivers are capable of routing low frequency content from ALL speakers set to "large" to the subwoofer out. Even your Pioneer does not route low frequencies from the surrund channels to the subwoofer, only from L, C and R.
2. LFE content is not distributed back to all speakers (but it should because the calibration is based on that assumption)
3. Low frequency content that is mixed to only one of the channels is not distributed to all loudspeakers (but it should because the calibration is based on that assumption)
4. LFE content that was not audible in the mixing process (when mixed with bass management) will wrongly become audible
The solution to all these problems is simple (switch all speakers to small) and should work with your calibration solution. What I like about your approach is that your optimization includes the mains. That's where all other solutions like Audyssey fail.
Best, Markus
I understand, but I do think that the LF in the surrounds IS sent to the sub when they are set to "small".
I will have to try "small" on everything, but my theater is down with a failed projector.
Markus, I'm not following you on 4., and your last sentence; could you please explain?
The LFE is basically a full normal channel. A low pass filter might most likely be applied in mastering. But while mixing you can route anything you like to the LFE.
When your mixing console is wired to a bass managed monitoring, then the LFE gets low pass filtered. You'll only hear frequencies filtered by the bass manager but the LFE itself can and will contain higher frequency content on the final master. That content was never part of the mix but will be heard in Earl's setup because he doesn't apply any low pass to the LFE.
Best, Markus
When your mixing console is wired to a bass managed monitoring, then the LFE gets low pass filtered. You'll only hear frequencies filtered by the bass manager but the LFE itself can and will contain higher frequency content on the final master. That content was never part of the mix but will be heard in Earl's setup because he doesn't apply any low pass to the LFE.
Best, Markus
A room's modal field changes with the number and position of sound sources. So any working optimization needs to be based on each and every relevant low frequency sound source.
There will be overlapping regions between the mains/surrounds and subwoofers when the standard 80Hz home theater crossover is applied. Therefore the optimization needs to incorporate the transfer function of all loudspeakers.
It's not enough to smooth the frequency response of a single subwoofer by EQing. When adding the mains, frequency response within the overlapping region will deteriorate.
There will be overlapping regions between the mains/surrounds and subwoofers when the standard 80Hz home theater crossover is applied. Therefore the optimization needs to incorporate the transfer function of all loudspeakers.
It's not enough to smooth the frequency response of a single subwoofer by EQing. When adding the mains, frequency response within the overlapping region will deteriorate.
Fs = 22 for the LAB-12:
Parts-Express.com:*Eminence Lab12 Generation II 12" Subwoofer | subwoofer sound horn driver driver bass 12" woofer 12" subwoofer car automotive
Not sure what you all are trying to prove here; this is not directed at Earl - I
know you are an expert.
It is fairly obvious that once you choose a sealed box size, the cone mass is
what determines Fc, and high mass is required with small boxes when a low
Fc is required. The only other alternative is assisted alignments or an LT.
This assumes a loose suspension, or Vas >> 3 x Vb.
If you are looking for low Fs to get a low Fc, even if you get one with 20 Hz Fs the box would have to be huge to not have Fc significantly higher than Fs. Vented is another story once you realize that you can tune below Fs, however vent velocity is an issue which usually leads to the need for passive radiators or else a very large box and port.
For traditional sealed and vented types including assisted variants the small signal volume/bandwidth/efficiency trade-off is well defined by Small's K factor.
Efficiency suffers with increasing Xmax for large signal considerations, however this can be offset with more magnet (cost) and good thermal design and is not locked to any fundamentals other than practicality.
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But then that's an error in the mix since there shouldn't be HF in the LFE. And I was under the impression that the LFE channel had a lower sample rate.
80Hz was just an example and I didn't mention Audyssey in my last post
But honestly I don't recommend using anything higher than that.
Very interesting - thanks for that link Markus. You really have to keep up on tis stuff since it changes so fast. I was shocked at how fast my Home Theater book was obsolete. The Audio Transducer book has some obsolete stuff, but most of it is still valid, but the HT stuff changes by the year.
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