Issue with Sequel II's Woofer (TORN)

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Chippieboy

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I had a torn woofer cone about halfway up. (not at the surround or the spider, in between them)
I called Martin Logan tech support looking for a replacement woofer. They suggested the only compatible replacement. It was: Scanspeak Discovery 26W/4534G 10" Aluminum Cone Woofer 4 ohm.

These were slightly bigger and I had to modify the enclosure hole to fit them.

The Scanspeak’s were very well built. I could not wait to hear these things. After I fired them up, the speakers sounded terrible. They have this boomy sound that I can’t get rid of. Really peaking around 100HZ. I have tried to equalize them down a bit but am losing all the good stuff above and below that 100HZ. I can’t stand to listen to these things anymore. Any suggestions from the group?
I know used speakers that age have issues. I can not afford anything decent that is new. I'm looking for other used ML's but have no idea what to do. I hate to say it, but I even previewed some used SoundLab's. I did like them but they are used as well and I know I will have future issues. I really miss listing to music. It's been a few months now. Please HELP

Here is more to the story if interested:
A few years back I purchased a used pair of Martin Logan Sequel II’s

They were at a Pawn Shop at a very good price and I could do a 9-month Layaway plan. I could not resist.

After about a year, they sounded a bit dull. I washed the panels in the shower and it brought them back to life. A few months later, the same thing. I read somewhere that Martin Logan supports their products for a lifetime. I ordered new panels. Installed the new panels and was very, very satisfied. Months later I heard some popping from the right speaker. I decided to have Power Amp serviced thinking premature clipping as it is circa the 1990s. They were some minor issues but nothing that would cause the popping issue. While the amp was being serviced I decided to rebuild the crossovers. I was using a Bryston B3 Amp while the main amp was being serviced. That amp had sufficient power if I did not drive the ML’s too hard. The new caps in the crossovers really brightened them up. But still random popping. New caps in the crossovers, different amp, and still the popping. One day the bass was really weak on the right side. I rang out the woofer and it was infinite ohms. Upon careful examination, I noticed the woofer was torn about halfway up on the cone. That must have been the popping. I called Martin Logan tech support looking for a replacement woofer. They suggested the only compatible replacement. It was: Scanspeak Discovery 26W/4534G 10" Aluminum Cone Woofer 4 ohm.
 

JonFo

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The Scanspeak’s were very well built. I could not wait to hear these things. After I fired them up, the speakers sounded terrible. They have this boomy sound that I can’t get rid of. Really peaking around 100HZ
This could be a couple of things, starting with the fact that maybe now that the woofer is actually working as intended, it is now energizing a room mode based on location. If you move the speakers further from the edges of the room, does that lower the peak?
BTW- Invest in a UMIK1 (~$100) and a copy of REW (free), as it is a required tool for setting up a serious audio system.
Audiophiles without a measuring system are like 'carpenters' without a tape measure nor a square-edge.

Secondly, could be a driver to crossover slight miss-match, as this is not the 100% same as the original. Some external EQ will address that.

Thirdly, it could be how the speaker is connected to the amp. From your other post, you now have a Sunfire Cinema Grand amp.
Since that amp has two flavors of output, part of the issue might be that you are powering the Sequels with the Current source output, which includes a 1 Ohm resistor in the path. This will skew the bass XO and is rather a sloppy sound. Try using the Voltage source output.

Or better yet, bi-amp the sequel, using the Current source to power the panel (as that will reduce the high-end a bit, which with new panels might be a bit bright) and the voltage source (no resistor) to drive the woofer input. Remember to remove the binding straps on the Sequel inputs.
 

msimanyi

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JonFo, can you recommend a resource for the UMK1? It appears the company itself is based out of Hong Kong, and I don't know if ordering from them becomes a hassle with U.S. Customs.
 

Chippieboy

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Okay JonFo, thanks for all your input.
First: They sounded pretty good for a number of years where they were placed in the room. About 30 to 35 inches from the wall behind them. I can not move them out any further as they are in the direct path from the front door entry to the rest of the house and the other walls will not work for placement, my 2 bedroom house complete with living room, dining room, and a good size kitchen is only 750 square feet. I will give it a try moving them out further just out of curiosity. It was the last few months that the popping started when I replaced the woofers. I know they are not an exact match but it was the best ML techs and this forum could do.
I just purchased the UMK1 and Mini DSP from Amazon. As stated above, I was skeptical of the Hong Kong website even though they were almost half price. I will give that a try when it arrives next week. (I can't wait)

Second: I do believe it might be a crossover miss-match. I did replace all the caps in the Xover but it's the inductors that filter out the higher frequencies from the woofer. I hoping that the Mini DSP will fix that miss-match issue. Your opinion on that?

Thirdly: I do have the ML's bi-wired. Current side to the panels and the voltage side to the woofers. The binding straps were missing when I received the speakers that is what prompted me to try the bi-wire method.

Fourthly: yes the new woofers are getting a good seal, I increased the hole size with great precision and am using the original "T" Nuts to secure them. Should I put some sort of sealer, weather stripping etc.....under them?
Thanks again, you might have saved me from spending the price of a good used car again.
 

AlmostHome

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JonFo, can you recommend a resource for the UMK1? It appears the company itself is based out of Hong Kong, and I don't know if ordering from them becomes a hassle with U.S. Customs.
I'm not JonFo, but Parts Express has the mike I think.
 

Chippieboy

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I thought the same thing about the Hong Kong issue so I ordered a combo package from Amazon, it will arrive in a few days.
Here is the URL for the combo, you can just get the mike separate as well. I must say that the Hong Kong site was almost half price.

 

Heyfey

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Hi Chippieboy,

I had a pair of Sequel IIs that I did a woofer replacement for and I kept and still have the originals, which were in good visual and operational condition. I had just replaced the caps and got new panels, so I was doing an almost full refurbish. They are 31 years old, but if you want them (and if they still fit given the cabinet modification you made) you can have them. If so I'll send to you and email a copy of the shipping receipt and just send me a check for shipping after you get them. You're in the Bay Area and I'm in So Cal (city of Orange), so shipping should be $30-40. And I'd verify they are working before shipping. Or if you'll be in So Cal just pick them up, they're in the Scanspeak boxes and two would fit in a carry-on suitcase.

Bob Fey
 

Mirolab

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Hi Chippieboy,

Interesting to hear your experience with the Scanspeak woofers. I have a pair of SL3's, and while my woofers are fine, I was wondering if the Scanspeaks would be an UPgrade to the originals. Now I'm thinking maybe not.... I should just be happy that my original woofers still sound fine. I've just installed brand new panels, so that's why I'm looking into it.

That said..... I've never been a fan of bi-wiring. Every time I've tried it, on many speakers, it has messed up the sound of an already good speaker.
A jumper is just a piece of wire..... jumper your inputs together, and try the speaker as the M-L gods had intended, and see if the sound is more coherent.
I'm willing to bet it will sound better......... Miro.
 

JonFo

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I do believe it might be a crossover miss-match. I did replace all the caps in the Xover but it's the inductors that filter out the higher frequencies from the woofer. I hoping that the Mini DSP will fix that miss-match issue. Your opinion on that?
OK, if the XO has been modded, there might indeed be some mismatch.
A miniDSP will do the job much better, especially in the low-end.

Are you planning to go full active-XO, or just use the DSP on the bass?

One benefit of a full-active setup is that you can now tweak delay parameters for each output to time-align the impulses, which really helps with the panel to woofer transition as well as overall 'tightness' of sound. On my setup, I wind up delaying the panel by 0.6s (IIRC).
The other benefit is a much steeper crossover slope on the panel. Some people leave the passive elements in place and set the XO a bit higher (340Hz) than stock.

Do spend some time watching videos of REW usage and read some of the guides on how to measure speakers (vs the system), but realize that most of that is geared towards monopole point-source, and what we have is a dipole line-source speaker. To measure it requires some adjustments, such as ensuring the measurement mike is capture mostly the direct energy from the front of the panel, so when capturing the impulse response for the panel alone, the mic should be at roughly the mid-point of the panel and about 3' to 4' away, not further. For the woofer alone, traditional advice would apply, as, on the Sequel, it is a monopole point-source.
 

JonFo

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Thirdly: I do have the ML's bi-wired. Current side to the panels and the voltage side to the woofers. The binding straps were missing when I received the speakers that is what prompted me to try the bi-wire method.
So just bi-wiring, not bi-Amping?

One thing you can try right away is to use the Voltage source to feed the panels, as that removes the added resistor, and will not only brighten the top-end, it also lifts the overall output by a dB or two, which maybe will re-balance the low end better.
 

JonFo

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Fourthly: yes the new woofers are getting a good seal, I increased the hole size with great precision and am using the original "T" Nuts to secure them. Should I put some sort of sealer, weather stripping etc.....under them?
I assume the Scanspeaks came with a gasket for the basket to cabinet seal, and it is in place, right?

If you just have metal speaker basket to wood cabinet as the seal, that is not enough.

The screws generally self-seal if the t-Nut is fully inserted and locked.
 

JonFo

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A jumper is just a piece of wire..... jumper your inputs together, and try the speaker as the M-L gods had intended, and see if the sound is more coherent.
While I'm with you on the futility of simple bi-wiring, what Chippieboy is doing goes a bit further, as he is using two different outputs from his Sunfire amp to feed each segment of the speaker, one of which has added resistance (1-Ohm), which does indeed measurably change the frequency response of the panel.
 

Chippieboy

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Miro, To tell you the truth, I can't hear much difference between Bi-Wire and not Bi-Wire. I had the Bryston as a single pair of wires, it sounded great but did not have as much punch as the Sunfire. I used the bryston while the Sunfire was getting a tune up.
I did try both ways of wiring with the Sunfire.
Thanks for the pointers.
 

Chippieboy

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JonFo, I'm not sure about going full active-XO, or just use the DSP on the bass. I really like the options, I thought about doing the Xover thing before I recapped the ML's.
Seems a bit complicated and some work but winter is coming so I will have some time. Since I'm in my 60's. My hearing is falling off after about 12K
The doctors say about 7K but I just did an online tone generator and I'm good to 12500 hz Not sure if that matters but I guess the graft will show the defects.
Thanks for the suggestions
 

mentorron

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Miro, To tell you the truth, I can't hear much difference between Bi-Wire and not Bi-Wire. I had the Bryston as a single pair of wires, it sounded great but did not have as much punch as the Sunfire. I used the bryston while the Sunfire was getting a tune up.
I did try both ways of wiring with the Sunfire.
Thanks for the pointers.
I have a pair of used (bought in 1999) original Aerius. The outputs were strapped when I got them, but thought I'd try bi-wiring (12 gauge) soon afterwards (to the same amp posts). Although I cannot prove there is any difference, I tried reinstalling the straps again at one time, and seemed to be less impressed by the sound output, so went back to the bi-wire. So to me it's psychological: as long as I know the bi-wiring is in place my brain seems to be happier with what I hear. However, my hearing is now on the decline as I'll be 80 years soon: my upper hearing limit at about 10Khz and tinnitus to boot. Luckily I have had no issues with the Aerius at all, so being in a smoke free, no grease-cooking environment and living in the NorthWest away from humidity and heat probably plays a big roll in their longevity. My components are just above "middle-of-the-road" and of late 1980s-90s vintage, so I can't compete with some of the systems you lads own ;-) Hope you all are enjoying your audio journeys ! I have, over the last 6 or so decades since my 1st tabletop RCA hi-fi !! :)💿🎼
 

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