[dallaire1]

Peanut gallery here

Could be wrong but if that is mlp you and or the subs could be in a suck out and trying to compensate with correction could easily cause what your issue is.

Try moving the subs a few (5-6”) inches forward and back and see how it helps. Sounds stupid but works.

You are correct about Dirac or any room correction software. I pull down the correction in Dirac if it is trying to compensate for a black hole.

[Bingenito]

Move the sub like 5-6” closer and away from the walls and reshoot and see if the correction is less to begin with. I would not boost anything 30hz or below. Easy way to chew up power and run out of xmax.

[SoCalWJS]

Yeah, I think it’s a pretty safe guess that the dip is being caused by Room cancellation at the MLP.

Even if it’s temporary, try moving the subs further away from the Front wall and measure again.

My 2 cents….

[dallaire1]

That broad valley around 50hz is not good.   You need to do the following by plotting 3 plots:
1)       M3 alone
2)       Subwoofer alone
3)       M3+subwoofer
 
All plots on the same graph.
 
-Brian

BRIAN'S RESPONSE

[dallaire1]

I think I'm going to have to carve out some time to track this all down. I am however going to run a 9v battery test at the input wiring on the subs to verify their correctness.

Thanks

[dallaire1]

Battery test checks out. The lower woofer IS pushing from the back of the cone forward into the MLP and the upper woofer IS pushing from the front off the cone forward into the MLP. I think I did in fact wright that incorrectly earlier.

[77SunsetStrip]

This suggestion assumes it can be done successfully without confirming the servo wiring is correct.  Maybe can disconnect the servo temporarily as high volume will not be needed.

Take advantage of some of the other features of REW.  Open the Generator function.  You can send any frequency to the NAD.  For example, start at 100 Hz.  Run only the main speakers, no subs.  Listen at the MLP.  Turn the NAD volume to zero.  Switch the polarity of the wires to 1, only 1, of the main speakers.  Turn the volume back up to the same level as previously and listen at the MLP.  The 100Hz should be clearly louder with one of the wiring configurations.  You can do this process at other frequencies also.  I know, this is basic and you may have done it already.  Just suggesting eat this elephant one small bite at a time.

Next perform the same checks with only one of the subs without driving the main speakers.  Change the drive wire polarity on one of the sub drivers.  Again, one of the wiring configurations should be louder indicating the drivers are in phase. 

Next do the same for the other sub.  Once that sub unit is phased properly, repeat the process driving both units to verify the two subs are in phase.

Then, run the main speakers and subs together to confirm everything is in phase for low frequencies.  Would then be left with confirming servo wiring. 

 

[Danny Richie]

That broad valley around 50hz is not good.   You need to do the following by plotting 3 plots:
1)       M3 alone
2)       Subwoofer alone
3)       M3+subwoofer
 
All plots on the same graph.
 
-Brian

BRIAN'S RESPONSE

That is exactly what I would start with.

Also, never try to shoot both channels at the same time. Do only left channel speaker and woofers separate and apart from right channel speaker and woofers.

[dallaire1]

Okay, it will take a bit to find the time right now but will definitely get it done and posted as described.

Do you have a simple FR shot of your system you can post ? Just want to know if I'm grossly off on what you consider a good looking low end ?
Vince

[dallaire1]

Huh ??

[Danny Richie]

Okay, it will take a bit to find the time right now but will definitely get it done and posted as described.

Do you have a simple FR shot of your system you can post ? Just want to know if I'm grossly off on what you consider a good looking low end ?
Vince

I've used measured responses to dial in phase and crossover points on Super V's and Super 7's. I did the same with the Line forces and many others, but never saved the responses as they really just applied to my room.

It was always pretty easy to get a flat response with the controls on the amps, and with my treated room I never had to use the EQ feature.

[77SunsetStrip]

Listened to Black Lotus previously mentioned as a bass torture track.  Very similar tracks with very low bass can be found from Freya Ridings, Mammal Hands, and way back Sarah McLachlan.  A Keiko Matsui track brings in several very large Japanese style drum strikes that are very low and resonate.  Other tracks with very low synthesizer bass.  Looking at all those with a spectrum analyzer, there is some content down to nearly 20 Hz detectable produced by my open baffle subs.  Four 10" drivers powered by a 250W amp.  Can crank up the subs to rattle pictures on the walls, but that ruins the rest of the music.

Took almost 6 months of experimenting, measuring, and listening to find the best overall setup.  Room based nulls and peaks are really difficult to tame.  Open baffle bass takes time and may ultimately just not be your cup of tea.  Took a while to get used to better depth, texture and detail instead of single sealed or ported sub one note room mode boom mistaken for great bass.

[Early B.]

Took almost 6 months of experimenting, measuring, and listening to find the best overall setup. 

This is essential -- time. Kudos 'cause 6 months is quick. OB servo subs ain't for the plug & play people. And it's a never-ending battle. A component change usually requires tweaking the subs. A few months ago, I was tweaking my No Rez!

[dallaire1]

Based on hearing all this, I can definitely get into playing with these subs ! But I feel real sorry for people that don't have the ability to measure with software, unless they were born with golden ears... Trying to find the time to dedicate.

[Early B.]

But I feel real sorry for people that don't have the ability to measure with software, unless they were born with golden ears... Trying to find the time to dedicate.

No need to feel sorry. I don't use software. Software can measure, but it doesn't detect clarity, nuance, detail, imaging, etc. Ears work better for that.

[dallaire1]

Perhaps Danny should point out in his kit literature "these subs will take at least 6 months to dial in" LOL, sorry just sounded funny.

[dallaire1]

Took a while to get used to better depth, texture and detail instead of single sealed or ported sub one note room mode boom mistaken for great bass.

This I have for certain noticed that I never "heard" how detailed the bass actually is, If I sit dead center its as though the bass itself at low frequencies has imagining qualities'. I think I'm going to have to implement amp boxes or I'm never going to be able to fix my dip in response that I'm told is making the amp clip. If I can't move them around, I can't fix the clipping.

[77SunsetStrip]

Based on hearing all this, I can definitely get into playing with these subs ! But I feel real sorry for people that don't have the ability to measure with software, unless they were born with golden ears... Trying to find the time to dedicate.

Measuring is definitely helpful, but does not provide a complete solution.  I found REW sweeps, 20 - 200 for example, not that helpful.  Using the Generator function with the RTA function provided the most helpful information.  The Generator gives you complete control to vary frequency over time.  You can slowly increase and decrease frequency and pause on a specific frequency as long as you want.  The RTA function will tell you the SPL level.  Easy to check SPL at 20, 30, 40, 50, etc.  Slowly moving up and down in frequency you can find the peaks and dips.  Found that process most effective to make adjustments that pleased my ear.  I had to fight a room mode peak at 50 Hz.  Following that process at your MLP will tell you if that spot is in a peak or dip.

Open baffle bass takes adjustment if you are coming from sealed or ported boxes.  I would never go back.

[Early B.]

Perhaps Danny should point out in his kit literature "these subs will take at least 6 months to dial in" LOL, sorry just sounded funny.

This isn't a Danny issue. Sometimes it takes many months to dial in a pair of speakers. For tube lovers, it could take a year or two to find the right tubes. Plus, your personal listening preferences constantly change, so round and round we go. Once you dial in your subs, your ears will "grow." (that sounds funny!)

[dallaire1]

I'm sure.