My system has had a series of alterations over the past few years that seem to have made some substantial cumulative changes. Now I seem to need some help retweaking it. Let me say at the outset, I'd like to avoid another "digital-now-is-so-much-better" or "such-and-such-is-mismatched" conversation about buying new stuff. Please work with me here and resist recommending some new gear (or a new house!) as the fix. So, that said, here's the story.
Equipment and setup
Speakers are MGIIIa's per post title. Yes, very old. However, they were rebuilt by Magnepan about 6 years ago - new membrane, wires, ribbons, socks and some other unspecified changes. They are now as new. At the time Magnepan said that all this made them the equal of the MG 3.7's. Maybe even better in the low end. I don't know, except that they were certainly improved greatly. The listening area is shown below and pretty much to scale. Although the room itself is large there's limited flexibility in changing it too dramatically. The door on the right side puts the home theater setup on the left side (which, incidentally, uses Maggie MMG's and a MMG C). Reversing the speakers and chair would put the back of the right speaker partially blocking the hallway. So, I'm kind of stuck with moving the speakers around the general region that they're in. The blue circles are tube traps, and they could be moved easily. The ones behind the TV are 16"x36" and do sonically improve matters on that end. The ones on the right are stacked 9"x37" + 11"x37" units. Their placement may or may not make sense, that's just where they fit best physically with best WAF.
The source is a Lumin U1 Mini feeding a Sonic Frontiers SFD-2 MkIII via BNC coax. It can also be routed through the Assemblage D2D-1 via AES/SBU. I'm not yet sure which I like better. The SFD-2 was further upgraded a few years ago by Parts Connexion (ex SF) and is tip top. This feeds a Krell KBL. The KBL's power supply was recapped and fixed a few years ago. A month or so ago the preamp itself was completely recapped during another repair in which a few transistors in the phase splitter were replaced . I mention this cause the KBL fixes did seem to have a significant effect on the sonics. More on that later. All this feeds a recapped ML No. 332. Though old, overall the system is in excellent shape electronically and sonically - extremely resolving, revealing, holographic and impactful. It's not clinical or harsh in any way, it just draws you in and raises the hair on your neck. I think I'd have to spend a LOT more $$$ to make a meaningful improvement, though more likely not, no real improvement just some kind of small difference.
![listening[506].JPG](https://www.diyaudio.com/community/attachments/listening-506-jpg.1021992/ "listening[506].JPG")
What's the problem?
Basically the bass was improved. Too much in fact. After the Maggie rebuild the system was substantially deeper and better controlled. The recent switch from the Node 2i to the Lumin greatly improved system detail and resolution in general. But the KBL rebuild seemed to have the most profound effect. It seems like the bass suddenly went an octave lower. It's also tighter and incredibly impactful. I suspect that the KBL now sounds like it did when it was new but the decay was so slow that it wasn't noticable. It's like the bass tone control got turned up, except there isn't one. Or, maybe, I've gotten used to less bass and now I'm just getting what I should have had all along? There's certainly a sense of hearing new stuff that I never heard before (we've all had that feeling at times, I'm sure).
So, what I want to do is fish for some ideas on how to tame the bass a little. I can rearrange the tube traps up to a point. Obviously the system is closed on one side and open on the other. I don't know what effect that might have. I've started moving the speakers around a little but any informed advice would be great. It wouldn't be too hard to slide the system to the left a foot or 2 if that would help. I'd also consider another tube trap or 2, but which ones and where would they go? Looking forward to ideas and lively discussion. Thanks and cheers,
Equipment and setup
Speakers are MGIIIa's per post title. Yes, very old. However, they were rebuilt by Magnepan about 6 years ago - new membrane, wires, ribbons, socks and some other unspecified changes. They are now as new. At the time Magnepan said that all this made them the equal of the MG 3.7's. Maybe even better in the low end. I don't know, except that they were certainly improved greatly. The listening area is shown below and pretty much to scale. Although the room itself is large there's limited flexibility in changing it too dramatically. The door on the right side puts the home theater setup on the left side (which, incidentally, uses Maggie MMG's and a MMG C). Reversing the speakers and chair would put the back of the right speaker partially blocking the hallway. So, I'm kind of stuck with moving the speakers around the general region that they're in. The blue circles are tube traps, and they could be moved easily. The ones behind the TV are 16"x36" and do sonically improve matters on that end. The ones on the right are stacked 9"x37" + 11"x37" units. Their placement may or may not make sense, that's just where they fit best physically with best WAF.
The source is a Lumin U1 Mini feeding a Sonic Frontiers SFD-2 MkIII via BNC coax. It can also be routed through the Assemblage D2D-1 via AES/SBU. I'm not yet sure which I like better. The SFD-2 was further upgraded a few years ago by Parts Connexion (ex SF) and is tip top. This feeds a Krell KBL. The KBL's power supply was recapped and fixed a few years ago. A month or so ago the preamp itself was completely recapped during another repair in which a few transistors in the phase splitter were replaced . I mention this cause the KBL fixes did seem to have a significant effect on the sonics. More on that later. All this feeds a recapped ML No. 332. Though old, overall the system is in excellent shape electronically and sonically - extremely resolving, revealing, holographic and impactful. It's not clinical or harsh in any way, it just draws you in and raises the hair on your neck. I think I'd have to spend a LOT more $$$ to make a meaningful improvement, though more likely not, no real improvement just some kind of small difference.
What's the problem?
Basically the bass was improved. Too much in fact. After the Maggie rebuild the system was substantially deeper and better controlled. The recent switch from the Node 2i to the Lumin greatly improved system detail and resolution in general. But the KBL rebuild seemed to have the most profound effect. It seems like the bass suddenly went an octave lower. It's also tighter and incredibly impactful. I suspect that the KBL now sounds like it did when it was new but the decay was so slow that it wasn't noticable. It's like the bass tone control got turned up, except there isn't one. Or, maybe, I've gotten used to less bass and now I'm just getting what I should have had all along? There's certainly a sense of hearing new stuff that I never heard before (we've all had that feeling at times, I'm sure).
So, what I want to do is fish for some ideas on how to tame the bass a little. I can rearrange the tube traps up to a point. Obviously the system is closed on one side and open on the other. I don't know what effect that might have. I've started moving the speakers around a little but any informed advice would be great. It wouldn't be too hard to slide the system to the left a foot or 2 if that would help. I'd also consider another tube trap or 2, but which ones and where would they go? Looking forward to ideas and lively discussion. Thanks and cheers,
Have you tried moving your chair away from the wall behind it? Having the chair close to the wall tends to enhance bass. Making an equilateral triangle of you and your speakers is a quick and easy test.
Do you have any measurement capabilities? If not, smartphone apps for RTA are pretty easy/cheap now. Apple microphones tend to be more consistent/accurate than Android, but if you want a little more flexibility, the IMM-6 from Parts Express is handy and includes calibration data which can be imported by some apps.
https://www.parts-express.com/Dayton-Audio-iMM-6-iDevice-Calibrated-Microphone-390-810
While you can position speakers through trial and error, having an RTA at your disposal helps speed things up and highlight issues.
Do you have any measurement capabilities? If not, smartphone apps for RTA are pretty easy/cheap now. Apple microphones tend to be more consistent/accurate than Android, but if you want a little more flexibility, the IMM-6 from Parts Express is handy and includes calibration data which can be imported by some apps.
https://www.parts-express.com/Dayton-Audio-iMM-6-iDevice-Calibrated-Microphone-390-810
While you can position speakers through trial and error, having an RTA at your disposal helps speed things up and highlight issues.
Excellent idea, thanks. You jogged my memory. I do have a sound meter, completely forgot about it. Used it years ago in another house and it was very helpful. I'll get on it. Cheers,