Subs to mains

[matt houser]

Trying to figure out why my mains are measuring so poorly in my room, I have been told that my ascend acoustics 340s are really nice speakers, The subs will measure pretty decently on their own but for some reason as soon as I add the means at an 80 Hz crossover they become an absolute nightmare, when I measured the fronts by themselves I realized that they are more than likely the cause as they are all over the place, as I raised the crossover point the System seemed to measure better and better as I crossed over toward 120hz, I am currently set at 120 Hz crossover which seems a little high and the system might be a tad bit boomy because of it but it was the only way I can measure anything somewhat smooth around the crossover

 

[lovinthehd]

Can you share more about your measurement methods and results, and share the measurements themselves? Maybe even more information about system/tools and what you did to setup to begin with. What's an absolute nightmare mean?

 

[matt houser]

This is A comparison of my mains and subs measured together with an 80 hurts crossover versus 120 Hz crossover

 

[matt houser]

Can you share more about your measurement methods and results, and share the measurements themselves? Maybe even more information about system/tools and what you did to setup to begin with. What's an absolute nightmare mean?

I use the Dayton audio umm-6 with rew, I will say right off hand that I am a newbie to this stuff but I have researched quite a bit recently to gain a little bit of an understanding, I am not using a mini DSP just the processor in my receiver but I have taken measurements after I’ve tweak any setting I even measured before and after odyssey, what I meant about absolute nightmare is the frequency responses were everywhere I had massive peaks and Knowles between 70 hurts all the way out through 140 Hz, from what I have learned it seemed like the front speakers poor responses were dragging down the subs responses with them, I have all these measurements saved on my laptop but I didn’t take screenshots of just the mains by themselves but before I introduced the mains the subs were measuring decently

 

[matt houser]

This was a final measurement with a crossover at 120 Hz after audyssey had been run, i’m not sure if this would be considered a good measurement or not

 

[William Lemmerhirt]

I would go back down to 80hz. Then add a couple feet at a time to the sub distance and see how it changes. It might shore up the dip, but at some point will get worse, so then bring it back to a good setting.
Also, the camera icon allows you to save a jpeg of the sweep and it’s much easier to read than a pic, which aren’t bad but...

 

[lovinthehd]

By gear and setup I meant more what avr, subs and other speakers are involved and where they're positioned and what steps you did to setup subs? Is a room correction routine involved?

I'm assuming this is a single mic position? Or multi averaged ? Where particularly? Blue trace is the 120 xo? Does look better but not if it creates sub issues (not localizable, just boomy?)

Like William said about using the tools for a screenshot rather than taking pics.

 

[matt houser]

My avr is the Denon x3500H, I have 2 HSU VTF-3MK5 subs and 3 ascend acoustics CMT 340SE’s in the front, 2 cbm 170se’s in the rear, I am limited on sub locations, I have one sub in the front left corner pulled out slightly, The second sub is behind the listening position on the mid back wall, I moved the subs around a bit and took measurements with rew before I ever implemented any type of room correction, I pulled the front left sub 2 feet away from the corner because I was getting cancellations when it was pushed all the way into the corner, all the measurements I did in REW were from 1 mic position in the primary listening seat which is all I really care about, The primary listening seat is just behind the center of my rectangular room lengthwise, I am in somewhat of a small room so the subs are fairly close to the listening position, about 7 to 8 feet away, I will also mention that it’s not an enclosed rectangle there are two doorways that are wide open two The rest of a pretty good size home, right now my only method of setting up the subs was by using Audyssey, I carefully took all eight measurements but focused on a pretty tight area of about A 4 foot bubble, I run the reference Odyssey curve with dynamic EQ enabled to try and get the house curve type of affect

 

[matt houser]

I would go back down to 80hz. Then add a couple feet at a time to the sub distance and see how it changes. It might shore up the dip, but at some point will get worse, so then bring it back to a good setting.
Also, the camera icon allows you to save a jpeg of the sweep and it’s much easier to read than a pic, which aren’t bad but...

I would go back down to 80hz. Then add a couple feet at a time to the sub distance and see how it changes. It might shore up the dip, but at some point will get worse, so then bring it back to a good setting.
Also, the camera icon allows you to save a jpeg of the sweep and it’s much easier to read than a pic, which aren’t bad but...

two questions the first one when I try and take a photo it keeps telling me the file size is too large, secondly and I am very curious on this one, I don’t have a mini DSP yet I do intend on getting one in the future but for now I am relying on odyssey to hopefully get me close, I have always read not to mess with odysseys distance settings after it is ran, If you could be so kind to offer a little bit of insight on this topic

 

[lovinthehd]

From an AH article on sub integration:

Distance

Seriously, how important can this be? You let auto-calibration take care of this for you, or if you’re feeling particularly hands on, you might whip out the tape measure, right? A word of wisdom: don’t underestimate the power of the distance setting in your A/V receiver. Obviously the primary job of the distance setting is setting a delay relative to your other speakers. Note, the distance reported by your receiver’s auto-calibration will be inclusive of any delay caused by signal processing happening inside the subwoofer (EQ, low pass filtering, etc.), which can add several feet to the distance per your tape measure. Above and beyond this, the distance adjustment functions as a phase control of sorts. Adding or subtracting a couple feet from the distance of your subwoofer is a viable way of getting rid of an ugly peak or dip around the crossover point. Again, to make the most out of this tool, one does need the ability to take measurements. Still, who would have ever thought such an innocuous setting could have that kind of power?

 

[William Lemmerhirt]

two questions the first one when I try and take a photo it keeps telling me the file size is too large, secondly and I am very curious on this one, I don’t have a mini DSP yet I do intend on getting one in the future but for now I am relying on odyssey to hopefully get me close, I have always read not to mess with odysseys distance settings after it is ran, If you could be so kind to offer a little bit of insight on this topic

Ok. The photo thing is frustrating, but it’s something with the site/server as far as I can tell. It has always had an issue with large photo files. I use Tapatalk on my phone and it asks me what size file I want to use. It’s much easier for posting regular pics but for rew screen caps it’s different I guess. I haven’t had a problem that I remember with posting from my laptop. Sorry, can’t help...
In general, I would say to trust Audyssey for distance and levels, but sometimes it misses just a bit. Think of phase and distance as kind of the same thing. When you run audyssey it uses the closest “measured” speaker. So all speaker measurements are based off that. When it measures subs, it does so acoustically as it “sees” them. When you factor in processing from dsp, and delay caused by the room and seating distances it rarely lines up with the tape measure. So if a sub is actually 8’ away, it can sometimes “measure” by audyssey differently. Audyssey adding distance shortens the delay it uses to time align(or phase align) with the mains. So what it’s doing is making them play in phase. Or in other words, at the same time.
So. When you add distance in the AVR to the sub channel, it makes it/them fire sooner because your telling it that it’s farther away than it actually is. So it wants to correct that. This can help with impulse response and group delay, and can “tighten” up the response. It can also fill in dips caused by out of phase(time)cancellations. That’s what you see when you measure subs and mains separately, and then when you combine them they get weird.
I haven’t read the article that @lovinthehd linked so if I’m talking crap then I’ll resign from giving advice lol. I have no doubt it covers whatever I said in a more granular way. Hope that can give some insight. Or at least confuse the hell out of you! Lol

 

[William Lemmerhirt]

From an AH article on sub integration:

Distance

Still, who would have ever thought such an innocuous setting could have that kind of power?

Totally agree. I wish it wasn’t so confusing. To the anointed it’s something else, but I feel like it’s like the “large/small” setting for speakers. Wtf!!!

 

[lovinthehd]

Then there's just flipping the phase switch on perhaps the sub behind you and see if that gives you stronger bass....

 

[matt houser]

I have flipped the switch on the back sub to 180, I lose quite a bit of response though