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First time with DSP on Subs

Mike_S

Well-Known Member
Purchased 2 Martin Logan Abyss 10 subs. Theses 2 new subs have been in use for almost 2 weeks now. Put them in almost the same spots as my old subs. They sound so much better, you can't even compare. They sound HUGE! Ton of texture, punch, impact, slam, dynamics, they go deep. Started off at 80hz @ 50% volume (following instructions). There were a bit boomy to start, but calmed down a ton during break in (ML says 50hrs). As they have broken in the volume has gone way down, currently sitting at 26%.

Vintage setup, stereo subs, running off the main speakers using speaker level inputs. Running main speakers full range. Tried doing RCA splitting the signal, cutting low end on my mains. It was a wireing mess, and sounded bad.

These have built in DSP, didn't think I would use it. But after a week, ordered the mic, downloaded the software. Took about 20min to do both subs. Thought there was a little bit of a standing wave at my listening spot, but didn't realize it was that bad. Might move the subs around a bit later. After DSP, man, that is a flat curve, did not expect that. Started with the left one, you can see, the right is far less jagged after doing the left. It would be nice to do both at the same time, but can't figure it out.

The 1-2k bump was my other half on the phone and playing with the dogs, there is never any piece.

What can I do better? What needs to be fixed? Do I need to mess with placement a bit?subs.jpg

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That's not a horrendous before- curve. 10dB variation is nothing over small bandwidth ranges, in the bass. I don't see anything that looks like a giant cancellation, so you're probably good. You might find a location that's slightly better, but don't expect huge improvements from that.

Do the subs have the ability to do time delay adjustment? I've had some cases, where even a millisecond or two, here and there, made a huge difference, blending with the main speakers. That can be a rabbit hole to fall into, but it can give astonishing results, if you're diligent and determined to find out where the best time alignment is.

Regards,
Gordon.
 
What I discovered in my room which is pretty heavily treated- if I move most anything I can see it when I take a new measurement. I put a 4x8 4" panel behind mine and the curve improved so I put another panel with it- response suffered. Pointing my sub just 5-10 degrees differently has effects. BTW- your room is a open environment- mine is closed. A open room like yours will pose challenges that I don't have. My sub is actually behind me equal distance as my mains. I have mine in a corner. I tried it in the middle of the room, on it's side, right side up and upside down, and with more and less fill. I am not sure what is behind you but you may not have a bunch of options for location. Keep experimenting. Lastly that pot in front of the left one, try measuring without that there. Your ports should be able to breath, no closer to a wall or obstruction than the diameter of your port. My port is 6" so mine just happens to face out into open space.

Edit: I see this is a sealed enclosure so in your case, never mind regarding my port direction comment.
 
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That's not a horrendous before- curve. 10dB variation is nothing over small bandwidth ranges, in the bass. I don't see anything that looks like a giant cancellation, so you're probably good. You might find a location that's slightly better, but don't expect huge improvements from that.

Do the subs have the ability to do time delay adjustment? I've had some cases, where even a millisecond or two, here and there, made a huge difference, blending with the main speakers. That can be a rabbit hole to fall into, but it can give astonishing results, if you're diligent and determined to find out where the best time alignment is.

Regards,
Gordon.
Yeah, you can tell there was a big boost somewhere. Sadly just purchased new wires for the subs, don't have a lot of room to play with. There is no time delay on the subs, they do totally disappear, almost asking myself "are these on" but I can feel them.
Does it sound any better to you?
At first, there was less bass, it felt wrong. But listened to it for a while, noticed that things were tighter, more defined, more detail. After a day, turned down the sub gain a little.
What I discovered in my room which is pretty heavily treated- if I move most anything I can see it when I take a new measurement. I put a 4x8 4" panel behind mine and the curve improved so I put another panel with it- response suffered. Pointing my sub just 5-10 degrees differently has effects. BTW- your room is a open environment- mine is closed. A open room like yours will pose challenges that I don't have. My sub is actually behind me equal distance as my mains. I have mine in a corner. I tried it in the middle of the room, on it's side, right side up and upside down, and with more and less fill. I am not sure what is behind you but you may not have a bunch of options for location. Keep experimenting. Lastly that pot in front of the left one, try measuring without that there. Your ports should be able to breath, no closer to a wall or obstruction than the diameter of your port. My port is 6" so mine just happens to face out into open space.

Edit: I see this is a sealed enclosure so in your case, never mind regarding my port direction comment.
I know there is a need for panels behind the speakers, that is in the works once I recover from the sub purchase. That plant was there before the sub, and it needs a new home, but I use the plant lights for my system. Will figure that out. Yes, no ports, they are sealed 3x10. The subs do have wireless, but would need to buy a bunch of cables to run in between my pre & power amp.

Right now it sounds great, and think the DSP line is smooth, but will move things around, play with the software to see what happens. Might be able to test each sub now in around 5 min each.
 
It would be interesting to see the curves on a 1/3 or 1/6 octave scale vs the 1 octave scale.
Not sure it can be changed, this is from the PDF it spits out when your done. Might be able to change the graph when testing. Will play around with it.
A tasteful blending of your socks with the area rug.
LOL, my socks, they were wet, just got back from taking my Blue Healer to the dog park. You can see all her murder also on the rug, she loves to see what's on the inside of any toy.
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One thing that's different now, is that with the compensation- the subs were actually effectively rolling off at a lower frequency, than they are now. The compensation looks to have cut some of the lower bass, and added some upper bass.

That said- it MIGHT be beneficial, to try a lower crossover point. Given those speakers should easily go down to 50Hz- that might be a good test point.

Regards,
Gordon.
 
I have this big smile. I saw the socks and said those be mine most days. Good looking dog you have there!!! Strong looking animal! My dogs are called cute- strong is much better!
 
One thing that's different now, is that with the compensation- the subs were actually effectively rolling off at a lower frequency, than they are now. The compensation looks to have cut some of the lower bass, and added some upper bass.

That said- it MIGHT be beneficial, to try a lower crossover point. Given those speakers should easily go down to 50Hz- that might be a good test point.

Regards,
Gordon.
Was not alone when doing the test, there was a meeting going on the other room, the dog was fetching a ball. That is what the upper stuff is from. Am going to do it again when I'm all alone. As soon as you ask anyone in the house to be "quiet" for 5min, that is the only thing you DO NOT get!!

XO is set at 66hz right now, main speakers go own in the 38hz range. Tried cutting the subs over at 35-45hz, it just didn't work. Bringing them up sounds so much better.
I have this big smile. I saw the socks and said those be mine most days. Good looking dog you have there!!! Strong looking animal! My dogs are called cute- strong is much better!
She is a 5yo Blue Healer, still has a ton of energy, so we get out everyday, so I don't kill her. She is 35lbs of pure muscle, she lacks grace, but has all the power. She is both cute and strong.
 
Yeah, you can tell there was a big boost somewhere. Sadly just purchased new wires for the subs, don't have a lot of room to play with. There is no time delay on the subs, they do totally disappear, almost asking myself "are these on" but I can feel them.

At first, there was less bass, it felt wrong. But listened to it for a while, noticed that things were tighter, more defined, more detail. After a day, turned down the sub gain a little. <<snip>>

This is exactly what so many people miss about a proper subwoofer integration, they SHOULD disappear! Nice work.

I think I’d try the plant on a piece of Sorbethene or Dynamat on top of the sub instead of in front of it, but I do understand that aesthetics are important and the height would be wrong then, … looks very nice the way you have it arranged.

Don’t worry so much about the graph, if it sounds great then I’d run with it, the graph shows that you’re very close if not there within most people’s ability to perceive flat, and although delay matters, it matters less at subwoofer frequencies (within reason) due to the long wavelength to your ability to locate a source. As hard as I have worked to tune my systems and space over the years I don’t yet have a separate program for where the dog decides to plant herself in front of the speakers, whether I have an open laptop screen on the table in front of me, whether the blinds are open or closed on the sliding glass door, other things that cause reflection and damping in the room when real life is happening. I have done that in the past and I honestly don’t feel that it added anything to the enjoyment of the music (even though the tinkering part is fun).

Sit back and enjoy.
 
This is exactly what so many people miss about a proper subwoofer integration, they SHOULD disappear! Nice work.

I think I’d try the plant on a piece of Sorbethene or Dynamat on top of the sub instead of in front of it, but I do understand that aesthetics are important and the height would be wrong then, … looks very nice the way you have it arranged.

Don’t worry so much about the graph, if it sounds great then I’d run with it, the graph shows that you’re very close if not there within most people’s ability to perceive flat, and although delay matters, it matters less at subwoofer frequencies (within reason) due to the long wavelength to your ability to locate a source. As hard as I have worked to tune my systems and space over the years I don’t yet have a separate program for where the dog decides to plant herself in front of the speakers, whether I have an open laptop screen on the table in front of me, whether the blinds are open or closed on the sliding glass door, other things that cause reflection and damping in the room when real life is happening. I have done that in the past and I honestly don’t feel that it added anything to the enjoyment of the music (even though the tinkering part is fun).

Sit back and enjoy.
Yeah, once you can no longer tell that all the speakers are working, they are totally working!
Subs are on spikes right now, going to place some egg crate foam behind them, just to see what it does. Each sub is 56lbs, they are not light.
Appears there is phase adjustment. Not exactly the same as time delay, but kinda.
it's kind of cool, can dial in phase 1 deg at a time, also invert it. Right now running 0 phase but inverted. Played around with it a ton, this sounds best. Closest match was 90deg.
 
Think they are totally broken in now, say there are around 100 hours on them. As they have been breaking in, I keep having to turn down the gain. Started at 50, and now at 26-28. Adjusted the crossovers a bit, have my pre-amp tone controls set bypassed.

New Blue-Jeans cables have been installed. Running speaker wire to the speakers, from the speakers to the subs. Not if anyone has noticed, but BJ cables are no longer "budget" Spent over $400 on 6 cables. Their prices have totally gone up!

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What's the extra stuff on the speaker terminals (wires to the sub notwithstanding)?

And, why double feed a single channel to each sub?
 
“What can I do better? What needs to be fixed? Do I need to mess with placement a bit?”
***
I’d lower your left foot a little. Maybe go with two different colored socks (complementary colors, of course). I’ve found that that helps considerably with time alignment.
 
What's the extra stuff on the speaker terminals (wires to the sub notwithstanding)?

And, why double feed a single channel to each sub?
Music Purifiers and litz ground wire, it cleans up the sound, hard to describe.

I did it both ways, only doing L/R for each sub, when I doubled it, the subs puts out a more more bass. I think when I only do one L/R it does not use both voice coils on the sub. Sadly, these little jumper wires cost a ton of $$. But totally worth it on what comes out of it.
 
I think when I only do one L/R it does not use both voice coils on the sub.

I doubt that's the case. All but certainly it's simply a summing network. Double feed can give a bit more input signal but nothing a tweak of the level control woudn't accomplish to get the same output.

I only have one sub with speaker level inputs. Did a comparison one time and found when dual feeding the relative output increased about 5dB. So, I had to turn down the level a bit to get back to same level it was single feed. In the end I left it single fed and simply turned the level adjustment a little higher.
 
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Nice system Mike. I would agree with whoaru99 about the phase alignment. Have you adjust it yet? I am not familiar with Arc Genesis but I use Rational Acoustics but for other purposes in the field. I also use REW but I use it for other parameters. If you are tech savy about tuning, REW or what the pros use, Rational Acoustics. If it sounds great to you already, great! You can probably improve your response even more if use trial and error and various measurement positions. If you want more coherence and timing with sub and speakers, I would suggest moving the subs closer to you close to the same horizontal plane of the speakers(if your space permits of course). Again, I would check the phase too.

BTW, I have data to proof how it worked in my difficult small near cube room. I only use one sub.
 
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