One ML Summit is 4-9db quieter.

[paulsop]

I've been struggling with this for months. It turns out my right channel is quieter than my left -- substantially.

I searched the forum, and this seems to happen from time to time.

My room is treated, and I've got the speakers on pads. I've experimented with positioning and treatment for months, as well as trying different amplifiers and swapping the physical speakers.

Also, the one which is quieter has a bass port breakup at frequencies (test tones) where the other one is fine. That's very odd to me.

I performed three nearfield measurements at different heights of each speaker with white noise. Apart from the speakers sounding quite different, one speaker was significantly louder.

I'm going to take a few more hours to really measure extremely carefully, but something seems up. Check below, and look at the -30db level. One speaker has a lot above that, the other doesn't.

I've had my installer in, as well as the person who sold them to me and they agree something is up. We thought it could be the room, which is symmetric and rectangular except for a small bar dip at the back where I have equipment racks.

Does this sort of thing happen a lot with ML products?

(BTW, I've got another small system at the other end of the room, and it sounds very balanced and great)

 

[Gordon Gray]

Paul,

One member had a similar issue. Turns out there was a wiring error between the x-over unit and the dynamic drivers. Drivers connected to wrong terminals.

Perhaps, that individual will chime in. I forgot the name but the thread appeared a couple of months ago.

Check the past threads and I'm sure you will find it.

Assuming this is not a new problem, sounds to me like this is the issue.

GG

PS: Found it. See Page 6 / Main Discussion Forum / "Bad Summit" thread - Sleepysurf

 

[FISH_MAN]

sounds like the panels are messed up ! call customer support also in addition could be something electrical inside messing up your bass

 

[paulsop]

Thanks, that sounds like something simple I could fix myself.

It could be what you describe, in that I really don't get the same high frequency dynamics from the right channel. Whenever I listen to a voice, if I turn to the left, I hear the voice coming from that speaker. When I turn to the right, there is voice, but not as clear. It sounds like all the voices are panned left.

The image is sort of left of middle.

I'll filled in a support form on the main site.

Thanks,

P

Paul,

One member had a similar issue. Turns out there was a wiring error between the x-over unit and the dynamic drivers. Drivers connected to wrong terminals.

 

[Craig]

I searched the forum, and this seems to happen from time to time...
Does this sort of thing happen a lot with ML products?

Not really, but what frequently happens is that someone will post on a forum only when they have a problem. This creates a disproportionate amount of posts with service issues and leads to a perception that an item is problematic. Only the service dept knows the percentage of faulty items vs total sales.

MartinLogan service dept has an excellent record with resolving customers issues and you should give them a try.

Something wired out of phase can sound like one speaker is weak and throw the image off to the weak side. It could be an internally wire crossed inside the speaker or a component out of phase or wired out of phase. Those would be areas to check if you haven't already.

By the way, Summits do not have bass ports and therefore port noise shouldn't be an issue. The bottom woofer is low and could possibly touch the carpet if the speaker is sitting low.

Are your speakers the same distances from the side wall as they are from the wall behind them? This can cause peaks and nulls from the waves lining up and colliding within the room boundaries. Just a thought to consider.

Again, the ML Customer Service team has a top reputation for taking care of thier customers and you may want to give them a chance to work with you.

Good luck,
Craig

 

[paulsop]

Duh. I should have known they don't have ports. All the stranger for this bass breakup.

To your question: The speakers are the same distance and angle from the wall, down to less than 1/4 cm. The room, while small, has a lot of correction (bass traps, first reflection absorbers, diffusers, etc...). I move the correction materials around depending on the speakers I'm using at the time, and right now everything is symmetric there as well. I've owned CLS's so I'm used to positioning electrostatics.

The only thing that destroys symmetry in this room (basement) is near the back, where there's a 3' depression that leads to equipment racks. Right now though, I've put some panels to cover the depression, but it could couple at some frequencies. I don't think that would account for the measurable difference in loudness between the two.

Hope it's that crossover, or something else! I tore down the boxes and put them in my Garage.

I searched the forum, and this seems to happen from time to time...
Does this sort of thing happen a lot with ML products?

Not really, but what frequently happens is that someone will post on a forum only when they have a problem. This creates a disproportionate amount of posts with service issues and leads to a perception that an item is problematic. Only the service dept knows the percentage of faulty items vs total sales.

MartinLogan service dept has an excellent record with resolving customers issues and you should give them a try.

Something wired out of phase can sound like one speaker is weak and throw the image off to the weak side. It could be an internally wire crossed inside the speaker or a component out of phase or wired out of phase. Those would be areas to check if you haven't already.

By the way, Summits do not have bass ports.

Are your speakers the same distances from the side wall as they are from the wall behind them? This can cause peaks and nulls from the waves lining up and colliding within the room boundaries. Just a thought to consider.

Again, the ML Customer Service team has a top reputation for taking care of thier customers and you may want to give them a chance to work with you.

Good luck,
Craig

 

[sleepysurf]

'Twas I that had the mis-connected woofer issue (see thread... http://www.martinloganowners.com/forum/showthread.php?t=9648). However, that only affected the bass response, not the highs.

I'm curious though, what source are you using for the white noise, and exactly how are you measuring it? If it's from a CD, or d/l, are you entirely sure both the left and right tracks are exactly the same? You also should bypass your preamp, and eliminate any other variables in your measurement technique.

What I'd suggest (although it takes a little effort), is to nearfield measure one speaker using just ONE channel of your amp, then move the other speaker to that exact room position, and measure again at the exact same height, using that same amp channel. If you are still seeing a major disparity, then something is definitely wrong, and as folks have pointed out, Jim Powers and his service staff are excellent resources.

Keep us posted!

 

[paulsop]

Hey there,

I used Logic Audio's test oscillator on a Mac Pro that's in my equipment rack. The test oscillator can generate white and Pink test audio at various calibrated levels, as well as the usual SIN, SQUARE, sweeps, etc... It's used to calibrate audio consoles. Here's an image someone took of it: http://compusition.com/img/tutorial/livelogic/logic_dummy_signal.png

This is a good tool, as you can also drop in a parametric EQ to check specific cross-over frequencies.

To measure an Earthworks measurement microphone was used. URL at http://www.earthworksaudio.com/26.html and this was mounted in a shockmount, and recorded with an Apogee Duet to Audacity on a separate computer, recorded nearfield, at 3 heights, 19" from the speaker, recorded one speaker at a time.

I like recording from battery power, with a powered audio interface as it lets me be free from any mains contamination. Usually I use something like Spectrafoo ( http://www.mhlabs.com/metric_halo/products/foo/ ) to perform the measurements, but today I was just messing around, and I'd have to bring some other equipment downstairs to use Spectrafoo.

I agree with you 100% that I might have something wrong with the pre-amp, amp, cables, etc... I'm going to need to perform a more rigorous systematic test when I have a free day. I started drafting the test plan today. Who knows!?

As for ML Support, I'm sure it's great. I hope I don't come across as ML bashing! I've owned ML products for over 10 years (CLS, CLSIIZ, and now the Summit). There are a few other systems in my house (a horn loaded Klipsch system, a large HT with Reference 3A La Suprema's, a Flea-watt SET/Lowther, a little Rega system, and a music/recording studio).

Thanks again for the suggestions,

Best,

Paul

I'm curious though, what source are you using for the white noise, and exactly how are you measuring it? If it's from a CD, or d/l, are you entirely sure both the left and right tracks are exactly the same? You also should bypass your preamp, and eliminate any other variables in your measurement technique.

What I'd suggest (although it takes a little effort), is to nearfield measure one speaker using just ONE channel of your amp, then move the other speaker to that exact room position, and measure again at the exact same height, using that same amp channel. If you are still seeing a major disparity, then something is definitely wrong, and as folks have pointed out, Jim Powers and his service staff are excellent resources.

Keep us posted!

 

[Horchem1972]

If you have a db meter,play a test tone through each speaker separately.While the test tone is playing hold the db meter a foot in front of the speaker.If one speaker plays louder than the other you will be able to tell.Holding the db meter that close,will completely remove any room anomalies you may have.

 

[RoboRob]

Sounds like one of the panels is End Of Life...

 

[sleepysurf]

Well, you certainly have the tools and knowledge to definitively measure them in a controlled fashion. Looking forward to seeing the results!

If there is indeed a problem, it'll be interesting to hear what ML suggests. I think it's a bit early for (legacy) Summit stat panels to be going bad, but it's certainly a possibility. However, I'm more inclined to think it might be something else. Has the original owner been forthright about any prior issues? ML has a step-by-step guide for DIY replacement of the woofer power modules, but I don't know if replacing the power supply for the panels is also a DIY option.

 

[MrBT]

Did you finally find what's wrong?

I'm currently having the same issue with one of my VISTAs. All troubleshooting lead me to foulty panel. Did almost everything: swap speakers (LR>RL), PSU boards, even panels and problem still followed the same panel. Right now my panels are drying up from yesterdays bath . Will see if this helps. If not than couple of hundred $ for a new panels.

 

[ronenash]

Hi all,

I had this problem a year ago with my Ascent i. It turned out that one of the power supply boards was faulty. As strange as this seems the board that was faulty was on the speaker that was loader. Talk to Jim Power at ML and he can assist. Don't rush into replacing the panel.

Ronen

 

[Jungle Jack]

Hello,
I was able to get a brand new pair of panels for my Vantages because of a 1-2 db disparity between channels free of charge. So long as you are the original owner, you might want to try to get the panels covered under warranty if that is the case or the power supply. Whichever is causing the issue.
Cheers,
ML

 

[MrBT]

It looks like the worst case scenario. From 500Hz and up there is 5db difference between panels. Washing panels didn't help. :-(

By qkizz at 2010-01-11

 

[sleepysurf]

Notwithstanding the difference between the two speakers, that's a pretty irregular frequency response! Not even close to being smooth (very bass heavy, and treble rolling off).

However, if you conducted the measurements in the controlled fashion mentioned above (each speaker in the exact same room position), then there's clearly a problem with one (or both). Time to call Jim Powers at ML. Given your testing capability, he'll probably suggest a few more diagnostic measurements.

 

[MrBT]

irregular frequency response.......well, I'm during setting up my new temporary listening area (which is very far from being perfect) and driven by curiosity I just plugged in sub in the system. Also experimenting with room treatmets etc.