Too much bass/room resonance issues?

[revah]

Hello everyone.

I just found this forum while poking around yesterday, and I'm hoping the collective wisdom of this group can give me suggestions for a new problem I'm experiencing.

I've been upgrading my (2 channel only) system piece by piece. I've had a pair of ML SL3s for a few years now, but I've been driving them with a mediocre old preamp and power amp. I upgraded my CD player last year to an Arcam DV-79. A couple of weeks ago, I finally took the plunge and got new gear that is worthy of the SL3s, a Conrad-Johnson PV-14LS2 preamp and MF-2500A power amp. The good news is the system overall sounds 1000% better than before. The bad news is that I now have too much bass - wild, wooly, uncontrolled bass between about 50 and 150 hz. Bass I never knew I had before because the amp couldn't deliver it. It seems it's a room resonance issue, but maybe there's something else I'm overlooking.

Things I've already done:
1. moved the speakers all over the room. Finally left them exactly where they were before - 54" from the side walls, 43" from the front wall, about 7' apart. Incidentally, I settled on this spot by ear, then did the calculations in the manual and it was within 1/2" of the theoretical optimum.

2. installed the speaker spikes. I know, I should have been doing it all along, but just hadn't gotten around to it. This helped tremendously.

3. set the switch on the speakers to the -3dB bass position. This also helped.

issues:

1. the side and front walls are quite irregular, with many doors, windows, and alcoves. Don't know if that's a good or bad thing acoustically.

2. the speaker wires unfortunately have a long run - 25'. Can't really do much about this because of the room layout.

3. the system is in my living room, so traps, panels and other acoustical treatments are just not an option.

I'd love to hear any and all suggestions and other people's experiences- speaker cables, interconnects, equipment stands, spikes, etc.

Thanks.
Sami

 

[kach22i]

I'll assume you are not on a concrete floor.

Sprun floors on houses constructed out of wood, may act as a diaphram. This diaphram will vibrate and heave (mechanical energy) with the bass until the sound is absorbed.

This will muddy the bass, and make too much of it at certain frequencies.

Products from Brightstar or Townshend (sand innards) placed under the speaker will absorb the excessive energy. You can make your own sandbox/base platform or try concrete padio pavers if low on time and cash.

Look at these two member systems:

NO. 2
http://www.martinloganowners.com/~tdacquis/forum/showthread.php?t=163

NO. 42
http://www.martinloganowners.com/~tdacquis/forum/showthread.php?t=531

 

[beanbag]

Radio Shack SPL meter
BFD equalizer

 

[C.A.P]

having to much bass is not necessarly a bad thing with Logans , you can tame bass better than you can try to make it , you would bee suprised at the room treatments that will fit in your decor these days ,

 

[kach22i]

Energizing the room with sound energy can be a tricky thing, nipping it in the bud (or base) might sound drastic................but it works like no other fail-safe method.

 

[roberto]

Hello everyone.

I just found this forum while poking around yesterday, and I'm hoping the collective wisdom of this group can give me suggestions for a new problem I'm experiencing.

I've been upgrading my (2 channel only) system piece by piece. I've had a pair of ML SL3s for a few years now, but I've been driving them with a mediocre old preamp and power amp. I upgraded my CD player last year to an Arcam DV-79. A couple of weeks ago, I finally took the plunge and got new gear that is worthy of the SL3s, a Conrad-Johnson PV-14LS2 preamp and MF-2500A power amp. The good news is the system overall sounds 1000% better than before. The bad news is that I now have too much bass - wild, wooly, uncontrolled bass between about 50 and 150 hz. Bass I never knew I had before because the amp couldn't deliver it. It seems it's a room resonance issue, but maybe there's something else I'm overlooking.

Things I've already done:
1. moved the speakers all over the room. Finally left them exactly where they were before - 54" from the side walls, 43" from the front wall, about 7' apart. Incidentally, I settled on this spot by ear, then did the calculations in the manual and it was within 1/2" of the theoretical optimum.

2. installed the speaker spikes. I know, I should have been doing it all along, but just hadn't gotten around to it. This helped tremendously.

3. set the switch on the speakers to the -3dB bass position. This also helped.

issues:

1. the side and front walls are quite irregular, with many doors, windows, and alcoves. Don't know if that's a good or bad thing acoustically.

2. the speaker wires unfortunately have a long run - 25'. Can't really do much about this because of the room layout.

3. the system is in my living room, so traps, panels and other acoustical treatments are just not an option.

I'd love to hear any and all suggestions and other people's experiences- speaker cables, interconnects, equipment stands, spikes, etc.

Thanks.
Sami

Hola Sami, welcome to the club. Just thinking loud with a problem that I had sometime ago with a pair of SL-3, too much bass. The problem was the stat panels...they were almost dead. You could hear them working, but they lost their sensitivity. As soon as I changed the panels, the problem was fixed. Perhaps you could do the "shower" cleaning before change them, or try to demo another ML speaker to verify if the problem is the room or the speakers...hope this can help, happy listening,
Roberto.

 

[kach22i]

You could hear them working, but they lost their sensitivity.

Funny thing is just after I built my sand boxes, I changed the stat panels and entered a new world of balance..........................that was about eight years ago, had forgotten about that.

Vac first.

Wash as last resort.

Replace panels when all else fails.

 

[C.A.P]

now that you fellas mention it , I too had a bass boom before changing panels ,I never thought about it ! ( wow It just dawned on me as roberto said that) , because after I changed them I called Jim Power at ML and asked him about thier sensitivity and if new panels were more efficiant, he said wait a few weeks (it was like going through puberty again ) and last week it just seemed to start to bloom and all come together and WOW it is getting better every day !!!

good call guys

 

[revah]

Thanks, everyone, for your suggestions so far.

Roberto, it's been a while since I vacuumed the panels, so I'll definitely try that first. I don't really understand the "shower" comment. Do you actually remove the panels frrom the rest of the speaker and wash them? How do you disassemble them? I hope I'm not at the point where I have to actually replace the panels. The speakers are 1998 vintage. How much life should I expect from a panel? Also worth mentioning is that I live at the beach. The salt air is definitely a factor as well. I've just had to accept as a fact of life that all my electronics age faster here.

I'm also intrigued by the sandbox (or equivalent) idea. Kach22i, as you noted, I'm on hardwood floors, on the third floor of my house. Construction being what it is these days, it's not the most solid of foundations. I looked into the Brightstar stuff, and it might be worth a try. The dealer who sold me the c-j amps also carries Brightstar, so I'll see if I can try them out.

The BFD equalizer idea won't work for me because it's for subwoofers only as far as I can tell. I would not consider putting an equalizer into the main signal path.

Sami

 

[roberto]

Thanks, everyone, for your suggestions so far.

Roberto, it's been a while since I vacuumed the panels, so I'll definitely try that first. I don't really understand the "shower" comment. Do you actually remove the panels frrom the rest of the speaker and wash them? How do you disassemble them? I hope I'm not at the point where I have to actually replace the panels. The speakers are 1998 vintage. How much life should I expect from a panel? Also worth mentioning is that I live at the beach. The salt air is definitely a factor as well. I've just had to accept as a fact of life that all my electronics age faster here.

I'm also intrigued by the sandbox (or equivalent) idea. Kach22i, as you noted, I'm on hardwood floors, on the third floor of my house. Construction being what it is these days, it's not the most solid of foundations. I looked into the Brightstar stuff, and it might be worth a try. The dealer who sold me the c-j amps also carries Brightstar, so I'll see if I can try them out.

The BFD equalizer idea won't work for me because it's for subwoofers only as far as I can tell. I would not consider putting an equalizer into the main signal path.

Sami

Yes, you have to take the panels apart. Just follow Dan´s instructions at the tweak section of this forum. You can´t tell how long the panels last. As an example of this, here in Costa Rica, I have customers with original panels and they have over ten years old...and others that I just have changed them, with less than two years...and we don´t know what makes the panels to go dead.
Cheers,
Roberto.

 

[Shoe]

Bass issues

This is my fist post I am no longer hanging around the side lines. I have a similar set up. Sl3's power by CJ mf2500 and Premire 10 pre amp. Running two Rel Strata lll subs in stereo. My dedicated listening room is 13X30 with a concrete floor, double wall which makes the room 90% sound proof. As you can imagine bass was a huge problem. The bass issues were address by using bass traps in all the cornors and at the mid point of ceiling and wall on both sides and along the rear back wall. I must say that I no longer have any bass problems. The bass is very deep,clean and very articulalent The bass notes can easily be followed. This in turns brings the mid range and upper frequenices into complete balance with the lower frequencies. Image and focus is sharp with a 3 D to die for. The front and side walls all but disapear. Therefore I am a huge fan for bass trapping. I will post pictures when able. Thanks, Sam

 

[revah]

Shoe, I fear you may be right, that bass traps may ultimately be the only answer. However, I'm still holding out hope for another solution because the SL3s are in my living room and big 'ol tube traps in the corners and along the walls are just not an option.

I still intend to try the sandboxes, Brightstar or otherwise; haven't had the chance yet. I also need to go through the vacuuming/showering routine. I'll report back after those attempts. If those don't work, I don't know what I'll do. The sound above 100 hz is beautiful, but the bass is nearly unbearable.

Sami

 

[Statman]

If it's the WAF what about just using the Bass traps when you listen and remove them when you're not? Or is it just a decor thing? Just wondering. Shop Vacs work great on Logans.

 

[revah]

update on my bass problems

Hello again. I thought I'd give an update on the bass/room resonance problems I've been having.

Since my last post, I've done several things, with interesting results. First, I vacuumed the panels. I realized it's probably been too long since I last did it, as it helped the sound quite a bit. It also seemed to tighten up the bass, though I'm not sure why this should be the case, as the woofers are handling everything below 250Hz.

Next, I talked to the dealer where I recently bought my new c-j amps. I asked him what would be most effective at taming the bass problems I'm having. His response: 1) upgrade the power cords on the ML speakers and 2) try the Brightstar Big Rock isolation platforms under the speakers.

The Brightstars were an obvious choice; I wanted to try them anyway. As for the power cords, his answer was 'I can explain every piece of gear I sell here, why it works, etc., except the power cords. They work, but I don't know why.'

So I took home 2 Brightstar Big Rock 2 platforms and 2 Tara Labs Prism Reference AC cables, and got to work. I also stopped at Radio Shack and got a Sound Level Meter. After downloading test tones, I started running tests through the system to look at frequency response. BTW, thanks for the suggestion about the BFD equalizer. Even though I couldn't use their product, their web site has test tones and a spreadsheet for correcting and calibrating the Radio Shack meter.

Results.
1. The baseline test confirmed what my ears have been telling me. I have a siginificant bump of 5-10 dB between 55 and 120 Hz, with a secondary peak around 40 Hz.
2. The Big Rocks made a difference, which while not appearing significant on the frequency response, really helped tighten things up.
3. The power cords also made a difference, which I just don't understand at all. My engineering background is telling me this just shouldn't be so. While the difference in the bass was relatively small, the power cords did sharpen the overall focus of the system, making each instrument more clearly defined in space.

Conclusions.
1. The Big Rocks, at about $200 each, are worth keeping for the improvement they've made.
2. the jury is still out on the AC cables. At $500 for the pair, I haven't decided if the benefit is great enough to justify the cost. I'll listen for another week before deciding.
3. The problem is better now, but still not fully satisfactory. I'm going to keep looking for other solutions to try.

If anyone's interested, the frequency response data and graph is posted below.

Sami

	Baseline   With BR2   With Power Cords   With BR2 and Tara	
FREQ	SPL	SPL	SPL	SPL
16	81.5	85.5	82.5	85.5
18	85.0	86.0	85.0	86.0
20	84.5	85.5	84.5	85.5
22	83.5	84.5	82.5	84.5
25	87.0	89.0	87.0	89.0
28	88.0	89.0	88.0	89.0
31.5	89.0	89.0	89.0	89.0
36	92.5	92.5	92.5	92.5
40	93.5	94.5	93.5	95.5
45	87.0	88.0	87.0	88.0
50	91.5	91.5	91.5	91.5
56	99.5	98.5	99.5	97.5
63	100.5	100.5	100.5	99.5
71	99.5	99.5	99.5	98.5
80	95.5	95.5	95.5	95.5
89	94.5	94.5	94.5	93.5
100	98.0	98.0	98.0	97.0
111	98.0	97.0	98.0	96.0
125	91.5	90.5    90.5	91.5
142.5	93.5	92.5	93.5	92.5
160	90.5	90.5	90.5	90.5

Well shoot, I can't figure out how to paste an Excel chart into this message. The data above has 2 sets of numbers for each test, the raw reading and the corrected reading for the baseline, with Big Rocks, with AC cables, and with both. Sorry for the formatting, or lack thereof. If anyone can tell me how to post the chart, I'd very much appreciate the help.

 

[kach22i]

$500 for power cords is too rich for me, many people swear by them.

$400 for sandboxes, how is your carpentry work?

If the Brightstar's should ever suck too much high frequency energy or "toe tapping" energy from the speakers, you can add a steel plate under one cone.

You will have to adjust the angle on the speakers once you raise them, otherwise the high stuff shoots over your head a little.

Late in the day, what does that chart say again?

 

[revah]

Yes, $500 for 2 power cords is giving me pains as well. I'm just not convinced I'm getting enough bang for the buck here. I think I'd rather buy another $500 of CDs and get much more pleasure .

Unfortunately, my carpentry work is pretty much nonexistent. I couldn't take wood shop in high school because I was in the band, and it's been pretty much downhill from there.

I'll have to experiment with the tilt angle. The Brightstars add about 3" to the height. I thought that sitting or standing I was still in the plane of the panels, but I'll have to play around with it a bit and see if it makes a difference.

Sorry about the messy table before. I've cleaned it up a bit now. There are 5 columns of numbers. The first is the frequency, and 2-5 is the measured sound level at that frequency for baseline, with the Big Rocks, with the fancy power cords, and with both.

Sami

 

[Craig]

So I took home 2 Brightstar Big Rock 2 platforms and 2 Tara Labs Prism Reference AC cables, and got to work. I also stopped at Radio Shack and got a Sound Level Meter. After downloading test tones, I started running tests through the system to look at frequency response. BTW, thanks for the suggestion about the BFD equalizer. Even though I couldn't use their product, their web site has test tones and a spreadsheet for correcting and calibrating the Radio Shack meter.

You previuosly mentioned downloading test tones. Can you tell me/us a good web site or source for downloading test tones? I have the Radio Shack meter but lack a test CD.

Thanks

 

[DTB300]

You previuosly mentioned downloading test tones. Can you tell me/us a good web site or source for downloading test tones? I have the Radio Shack meter but lack a test CD.

www.realtraps.com has a nice one that you can download for free. I think they are MP3 Tones.

 

[Andre]

I had boomy bass when using Vampire speaker cable (single run), and when I changed to Audioquest heavy gauge bi-wire, bass and everything else improved!
Also try reversing the + and - on the bass terminals to make sure that it is not out of phase......
Lastly, check electrical polarity of spkrs and equipments and that you have a good grounding (no ac leaks on ground terminals)

 

[revah]

test tones

I got the Excel worksheet that includes the correction factors for the Radio Shack Sound Level Meter at this website:

http://bfdguide.ws/

The test tones were at this link:

http://bfdguide.ws/sinewaves/

The test tones are 1/6 octave tones from 160 Hz to 18 Hz. They are mp3 files, which I then converted to WAV and burned to a CD.

Sami