Podcast HomeTheaterUnited Podcast Episode 15 - Dave Upton on room correction and calibration with REW and Audyssey (1 Viewer)

[Dave Upton]

It looks like your crossover is set at 40Hz. Plus, I can't believe you're getting that kind of output all the way down to 10Hz.

Actually John this is very possible with room gain. Especially if the sub is corner loaded.

 

[John Dirk]

Well, my calibration stuff is here and we're projected to get as much as three FEET of snow through the weekend. So, I won't be going anywhere until Tuesday, once I get home this afternoon. Maybe I'll have a chance to try the stuff out. Hopefully the power stays on and my roof doesn't collapse.

LOL - I was just talking to a work colleague in your area and she said she same thing.

 

[John Dirk]

Questions that spring to mind:

What is your LPF of LFE set to in your AVR?
Do you have a lowpass filter set on the SVS?

Make sure Audyssey is off for your measurements - that is absolutely essential.

LPF for LFE = 120
Lowpass filter - Don't think so. Settings are as follows.
Gain = 50%
Phase = 0
Crossover = Disabled
Subsonic Filter = Bypass
Ports = 2 of 3 sealed

Actually John this is very possible with room gain. Especially if the sub is corner loaded.

Not sure what any of this means but the PB12 Plus/2 is a down firing sub. The ports are probably about 3ft from the front wall.

I'll be trying some new measurements later this evening with Audyssey off but the sub is almost certainly going to be replaced at some point anyway as it's nearly 15 years old. For the moment I'm just ecstatic at the idea of being able to finally see response curves. Lots to learn!

 

[JohnRice]

LOL - I was just talking to a work colleague in your area and she said she same thing.

Boulder by chance? The projection there is about the same as here.

 

[John Dirk]

Here are my measurements for today. I turned off Audyssey and also corrected my HTPC's speaker config as it was previously set for stereo. Since I'm almost always playing encoded formats or 2 channel music it doesn't usually matter but in this case it seems to have made a difference. Also tried a few different seats.

 

[John Dirk]

Boulder by chance? The projection there is about the same as here.

Evergreen, so not far.

 

[Dave Upton]

Here are my measurements for today. I turned off Audyssey and also corrected my HTPC's speaker config as it was previously set for stereo. Since I'm almost always playing encoded formats or 2 channel music it doesn't usually matter but in this case it seems to have made a difference. Also tried a few different seats.

View attachment 92036

So these sweeps are mains + subs? Have you taken sweeps with the subs off and the speakers running full-range?

 

[JohnRice]

I can envision myself spending weeks doing frequency sweeps.

 

[John Dirk]

So these sweeps are mains + subs? Have you taken sweeps with the subs off and the speakers running full-range?

These are the sub without the mains from each of my 3 front-row seats. I did capture the sub + mains. I'll plan to post those sweeps tomorrow.

 

[John Dirk]

I can envision myself spending weeks doing frequency sweeps.

I thought I'd been working on them for maybe an hour and then realized it had been 3 hours. REW is really quite fascinating. Just scratching the surface. I also have another app called TrueRTA which is pretty nice.

 

[Dave Upton]

I thought I'd been working on them for maybe an hour and then realized it had been 3 hours. REW is really quite fascinating. Just scratching the surface. I also have another app called TrueRTA which is pretty nice.

The other thing about REW, is that it has a ton of "hidden" features also.

Reading the help is a bit boring, but I've found some really cool stuff that way, like wavelet visualizations.

 

[John Dirk]

Here are the mains measured with and without the sub. The legend shows which curve is for each measurement.

 

[JohnRice]

Here are the mains measured with and without the sub. The legend shows which curve is for each measurement.

View attachment 92095

Clearly a room mode at 70Hz.

 

[John Dirk]

With the Pre/Pro market in somewhat of a state of disarray I've decided now may be the time to upgrade my aging SVS PB12 Plus/2 sub. Unless I'm measuring wrong in REW [see post #65] the sub drops off substantially after about 60 Hz.

After a good deal of research I've all but settled on dual SVS SB3000's but am definitely open to thoughts. A few of my own thoughts are below.

• My Legacy Focus SE's are rock solid starting at about 25 Hz and remain that way [70 Hz dip aside] throughout the lower range. The PB12 Plus/2 seems to lose considerable SPL at about 60Hz but does fine up to that point. What would the SB3000's [or similar] add? Is there much LFE specific content above 60Hz?
• Sealed vs ported - Since purchasing the Focus SE's I tend to disengage the sub for 2 channel listening. My understanding is the main advantage of sealed subs is they tend to be better controlled or more "articulate," but usually at the expense of some lower end extension. Since the Focus SE's are plenty articulate and controlled do I really need that from my sub or would I be better going with ported for the added SPL's below around 20 Hz?
• Please see pic. I've often heard the term "pressurize the room" in relation to what subs are supposed to do. Perhaps I'm taking that too literally but my room does not have an actual door, only an open entry way with blackout curtains, so it that something I should consider addressing?

 

[JohnRice]

With the Pre/Pro market in somewhat of a state of disarray I've decided now may be the time to upgrade my aging SVS PB12 Plus/2 sub. Unless I'm measuring wrong in REW [see post #65] the sub drops off substantially after about 60 Hz.

After a good deal of research I've all but settled on dual SVS SB3000's but am definitely open to thoughts. A few of my own thoughts are below.

• My Legacy Focus SE's are rock solid starting at about 25 Hz and remain that way [70 Hz dip aside] throughout the lower range. The PB12 Plus/2 seems to lose considerable SPL at about 60Hz but does fine up to that point. What would the SB3000's [or similar] add? Is there much LFE specific content above 60Hz?
• Sealed vs ported - Since purchasing the Focus SE's I tend to disengage the sub for 2 channel listening. My understanding is the main advantage of sealed subs is they tend to be better controlled or more "articulate," but usually at the expense of some lower end extension. Since the Focus SE's are plenty articulate and controlled do I really need that from my sub or would I be better going with ported for the added SPL's below around 20 Hz?
• Please see pic. I've often heard the term "pressurize the room" in relation to what subs are supposed to do. Perhaps I'm taking that too literally but my room does not have an actual door, only an open entry way with blackout curtains, so it that something I should consider addressing?

View attachment 92102

I would consult Dave regarding the 70Hz drop. I suspect that is due to the room and needs to be addressed with physical changes before any equipment changes.

I would suggest you stick with a sealed sub, especially with the Legacy mains. The last thing I'd want with that setup is any sloppiness in the bass. With such high performance main speakers, I'd want to try to go with a pair of SB-16s instead. I know, double the price, but remember your "no regrets" goal. I've lately been considering them as an option in my case.

BTW, the official LFE upper end is 120Hz. What is actually in soundtracks is another issue that's up to the engineer.

Oh, and the "pressurize" term is more of an expression of how it feels, rather than something literal. That one doorway isn't going to make a big difference.

 

[JohnRice]

I suspect Dave would recommend a pair of Rythmik E15HP2s. Another serious contender for me as well.

In fact, after going around in circles on the issue of new sub(s), and considering the space available in my room, I think a pair of those are now my front runner.

 

[John Dirk]

I suspect Dave would recommend a pair of Rythmik E15HP2s. Another serious contender for me as well.

In fact, after going around in circles on the issue of new sub(s), and considering the space available in my room, I think a pair of those are now my front runner.

I did take a cursory look at Rythmik but, to be honest, was turned off by their web site. First, they're still using Abobe Flash, which is End of Life as of December 2020. I know that has nothing to do with their actual product but it's still not a great sign for a tech guy like me.

I also couldn't find any warranty information in my brief look. I'll spend some more time on their site but, after recent experiences, Customer Service goes a long way for me and I don't have to tell you that SVS absolutely excels in that area.

 

[JohnRice]

I did take a cursory look at Rythmik but, to be honest, was turned off by their web site. First, they're still using Abobe Flash, which is End of Life as of December 2020. I know that has nothing to do with their actual product but it's still not a great sign for a tech guy like me.

I also couldn't find any warranty information in my brief look. I'll spend some more time on their site but, after recent experiences, Customer Service goes a long way for me and I don't have to tell you that SVS absolutely excels in that area.

Ask @Dave Upton . He has so much more experience with them than I do. And yes, their web site sucks beyond belief. The fact remains, their subs are very highly regarded, and you can get a pair of that model for $2,800 delivered. I think that might be your best choice. I bet they would put a pair of SB-3000s to shame.

They REALLY need to adopt a simple, turnkey cart like Shopify. Their store is extremely simple. I would know something about that.

 

[John Dirk]

Ask @Dave Upton . He has so much more experience with them than I do. And yes, their web site sucks beyond belief. The fact remains, their subs are very highly regarded, and you can get a pair of that model for $2,800 delivered. I think that might be your best choice. I bet they would put a pair of SB-3000s to shame.

They REALLY need to adopt a simple, turnkey cart like Shopify. Their store is extremely simple. I would know something about that.

Yes, it will be interesting to get Dave's take. On quick comparison here is what I see of interest.

Rythmik / SVS
Warranty == 2yr electronics,5yr drivers / 5 years unconditional
Free In-Home Trial == NO. Customer pays return shipping / Yes. 45 Days
Return Shipping == Customer pays / SVS pays
Service Method == Factory - Customer pays shipping/Insurance / Parts shipped free to customer
Support Method == Limited Phone/Email / Phone/Email/Chat
Web Site == Poor at best / Steller
Employees == 7 / 37


As for the actual subs, based on price anyway, the SB4000 would probably be the realistic competitor for the E15HP2. While I have never seen a sub in these price ranges with such an extensive control set as the E15HP2, I seriously doubt it would outperform the SB3000 or 4000 to the point of "putting them to shame." Not saying it isn't the better overall sub but it would have to be a whole lot better for me considering the price and anticipated support experience. At this point anyway, Rythmik would be a tough sell for me.

 

[JohnRice]

Forgive my hyperbole. It’s a hyperbolic world and I guess it rubbed off on me.