Sequel II improvements?

[Eppo]

My Sequel II's are 14 years old, and I used to be very happy with the sound. But now the panels sound dull, and the bass is muddy. I wonder what to do, go for new speakers, or upgrade the old ones. I hope someone can advice me.
The panels are 7 years old, and I will clean and shower them before replacement, a lot of information is available about this on this great site.
For the bass, I heard it is an improvement to change (after >10 years) the capacitors that are in the signal line. Does anyone have the schematics of the crossover? I see two quality Martin Logan capacitors with 15.0 -250 written on it. Does this mean 15uF/250V?
The rubber of the woofers still looks quite flexible.

Any more suggestions?
(I run the speakers with Krell KAV 300i and MIT Terminator 4 biwire).

Thanks,
Eppo

 

[JonFo]

Hi Eppo,

Welcome aboard!

Surprising that the panels would sound dull after only 7 years, but depending on conditions (light exposure, humidity, dust or smoke), they might be due for an early refresh.

The latest Sequel/SL3 panels are very nice and feature the new ClearSpar technology, so they look great. They sound very, very good as well, as the new vapor depositing technique for the mylar is better than before. I find these new panels play ‘louder’ out of the box than the old ones did out of the box.

When you state the bass is muddy, then the woofer is very likely in need of an update.
But then my 13 year old Sequels are not showing much strain. However, they’ve never been pushed in the bass, as they’ve always been crossed over at 60 or 80hz. I’m planning on updating tem next year.
I’d recommend an update. Not sure yet of which driver. If you really want to push forward on that, we can look into it on this thread.

I’ll let others reply to the crossover update. My approach has always been to just bypass the passive crossover anyway as the best means of updating the crossover is to go active and bi-amp.
If you’re willing to go in and mess with the crossover, then switching to active is a much more rewarding path. Let me know if you want advice on that.

If you haven’t yet , see some of the threads on panel updates, woofer updates and crossover tweaks on this forum for more discussion on this topic.

Cheers,

 

[raphant69]

Hi, Eppo and Jonfo,
I also have the project to refurbish my Sequel II's.
I mean I'm going to dismantle them completely, make a new glossy black "piano finish" on the boxes (this will be done by a professional coater), change the panels for the latest ones. I'm also going to take a look at the crossovers to see if it's interresting to change some capacitors on the signal path and test the woofers (a friend of mine is a kit speakers seller) to see if it's worth mounting modern(maybe aluminium)ones.
Anyway I will try to take a maximum of pictures and will start a new thread for this. I hope that I will have enough time to do all this before the end of the year!
Any woofers suggestions are welcome.

Kind regards
Raphaël.

 

[Eppo]

Thanks Johathan,

Do you know how to find out if the woofers are really causing the muddy bass?
I searched all over the forum, also in the archives, but I cannot find information about upgrades concerning the crossover and woofer specific for the Sequel II. Does anyone have this information?

Bye,
Eppo

 

[JonFo]

Thanks Johathan,

Do you know how to find out if the woofers are really causing the muddy bass?
I searched all over the forum, also in the archives, but I cannot find information about upgrades concerning the crossover and woofer specific for the Sequel II. Does anyone have this information?

Bye,
Eppo

A quick test you can do is:

1, Disconnect the bridge between woofer and panel inputs on the rear of the Sequel.
2. Connect the amp to just the bass section input
3. place a decent sounding speaker with similar sized woofer (10”) next to the Sequel for comparison. If you don’t have one, then borrow one from a friend.
Some of us are weird and have 16 or so speakers in the house, so it was easy to find a set that matched for me,

Play some pieces that have decent low and mid-bass. Dance music has a lot of low energy, but is frequently mixed poorly, so beware. Test on headphones first so you get a true sense of how it should sound.

Play the test tracks thought both systems, if the Sequel sounds ‘muddy’ then the driver definitely needs updating.

More later on which driver might be appropriate for this, as I guess I need to start the research on options for mine as well.

 

[MPS]

Hi Eppo

Since you mentioned dull sound on panels IMHO you should fix this problem first. If there is electrolytic capasitors in Sequels crossover these could be in need of replacement. Next step check power supply to stators ( contact professional service person). Maybe even new panels? Once you have fixed high frequency problems, it's more easy to hear if there actually is a problem with low frequency sound. Without proper higher harmonics the lows do sound muddy or soft.

 

[Eppo]

Hi,

I vacuum cleaned and showered the panels, and the result is that one panel is sounding very well now (ahhh, the famous ML sound is back again), but the other is still very moderate, so it seem that the panels need to be replaced (or repaired). I will swap the panels (L-R) to be sure the electronics are OK. Indeed it seems to be a matter of balance; if the panels are not right, the bass is also influenced.

But apart from this, I also took a closer look to the bass section, and I was surprised, and to be honest, also disappointed about the design. It is a very simple, straight forward setup. I used to build speakers my self, years ago, and always a lot of attention was paid to panel vibration reduction, cabinet design, resonant frequency damping, crossover correction, standing waves, etc. But the Sequel has a simple, straight forward cabinet with some damping wool only. The crossover is 12dB/oct, with only a coil in series, and a capacitor in parallel with the woofer (and a resistor+switch for bass output level). I never found that the bass quality (and a lot of people agree) was matching the sound quality of the panels, and now I understand why. This is really a beginners design, I hope ML paid more attention to this topic in their later models (I am sure they did because the reviews report much better panel-woofer integration).

Replacing the capacitor has no big improvement, I guess, since it is not it series with the woofer.

So I still have to decide what to do, upgrade the Sequels, and improve the bass section (if possible since the design is very basic), or switch to another system. If I choose for the last, I will look for second hand speakers. Can someone advice me what would be a good replacement (with better low section)? I also have to consider the WAF, so bigger than Sequel is not allowed. I did not follow the new developments and models for the last years, is ML still the best? Can 'normal' cone systems deliver the same quality now?
Please let me know (I know I may get shot by asking such questions in this forum, but I 'll take the risk)

Bye,
Eppo.

 

[DTB300]

So I still have to decide what to do, upgrade the Sequels, and improve the bass section (if possible since the design is very basic), or switch to another system. If I choose for the last, I will look for second hand speakers. Can someone advice me what would be a good replacement (with better low section)? I also have to consider the WAF, so bigger than Sequel is not allowed. I did not follow the new developments and models for the last years, is ML still the best? Can 'normal' cone systems deliver the same quality now?
Please let me know (I know I may get shot by asking such questions in this forum, but I 'll take the risk)

I will take a shot at this...

1. The new models, IMHO, have a better integration of the panel and the woofers with the Vantage and the Summit - sorry to say but I am not a Vista fan - but it is there for a price point below the Vantage. With regard to the older ML's the Aeon i and the Odyssey were two of my favorite sounding models - but the Odyssey will be larger than your Sequels. The Aeon i could be augmented with a sub for better bass.

2. Can cone driver speakers deliver the same quality as ML's? That is a personal preference item and cannot be positively answered. You will get as many "yes" answers as "no". FYI - If I were to buy a cone driven speaker, I would probably buy the Wilson Sophia's or the Aerial Model 9's, based on my listening sessions with them - not cheap speakers.

3. With regards to WAF...I upgraded from Sequel's to CLSIIz's which definitely pushed the WAF...but after a bit, she got used to the new speakers and the issue was over.

4. JonFo had some good ideas for you to pursue for an improvement in bass for the Sequel

Dan

 

[raphant69]

Bass improvement

Hi, Eppo and Jonfo

IMHO, there are many ways to improve these muddy bass on the Sequel II's.

I also used to built speakers myself, and there are two things to do first.
Remove the bass unit and swap the cheap damping wooll for modern sorbothane or "Deflex" plates. This will resolve a lot of standing waves problems.
Also, sticking battens between the front and the rear, and between the left and the right of the bass cabinet will increase its rigidity. You can also stick and screw the battens if you plan to make a new finish on the cabinetry, that's what I'm going to do.
These two things are cheap and easy to do and can improve consequently the "performance" of the bass cabinet.

Changing capacitors on the crossover won't do a lot but it will make a little plus.
Then, the big question is, for you and me, which new driver can be used?
I'm in the process of this research but I already think that it's better to use a very fast driver, with modern diaphragm materials like aluminium or aerogel.

I'm optimistic and certain that all these changings will transfigurate the bass integration of our good old Sequel II's.

Then, there is something else that can be done. I sometimes think that if I did not have a Mark Levinson monster to drive these babies, I would add a digital amp whith active crossover module at the back of the bass cabinet, just like on subs, and would have (almost) the same bass contol and integration you can have with the Vantage's and their digital icepower module. But this is another step...

Kind regards from France
Raphaël.

 

[Eppo]

Hi,

You gave some good suggestions.
There is already a batten between the front and back panel (glued). I bought my Sequels second hand, but I suppose this was done in the factory by ML. Indeed a second one between the side panels will make the cabinet more rigid.
On one speaker, I fixed bituminous damping pads on both side panels. This reduces panel vibrations, but the total bass output is also lower and this is not good for the balance between the ELS panel and the woofer. And although the quality of the bass it better now, it is still much too slow compared to the electrostatic panel.
So I agree that changing the woofer for a much faster unit, in combination with better cabinet damping and switch to active (as Jonfo suggested as well) will enhance the bass a lot.
But this is quite a bit investment (I have to change the panels also), so I will still consider buying other units.
Any comment on how to reach the high quality for the best budget is appreciated.

Bye the way: A local supplier can repair the panels, and instead of 12u Mylar (ML), he is using 5u thickness, and claims that this is an improvement. Any experience with this?

Thanks,
Eppo

 

[JonFo]

Hi,

...
Bye the way: A local supplier can repair the panels, and instead of 12u Mylar (ML), he is using 5u thickness, and claims that this is an improvement. Any experience with this?

Thanks,
Eppo

Eppo,

I’d be very wary of that approach resulting in better sound. For one, the factory panels have a very sophisticated vapor depositing method of putting the conductive surface on the Mylar. Also, the factory tensioning jigs and vacuum stretching are hard to replicate.

For $550, the new panels from the factory are very reasonable. I’d not risk my money on alternatives. If after buying new panels you wanted to play around with the old panels, then fine. But the best results will probably only come from a factory panel.

Now, woofers, that’s a whole other game. There, I do believe that DIY and third-party suppliers can play a significant role as many of us on the board can attest to.

I still need to go investigate the driver alternatives and do some modeling on them to see what would be a good match not only to the cabinet, but to the transfer point to the ESL.
Also, if one already has a Subwoofer, you can plan on getting a driver that is more focused on mid-bass performance than trying to reach ultra-low. I went that route on my Monoliths and it has worked out great.

In my opinion, a tricked-out and tweaked Sequel will sound better than a stock later-gen model in the same price range. Fundamentally, there is nothing wrong with this unit that some of the tips being discussed won’t cure.

 

[raphant69]

Hi, I completely agree with you Jonfo, it's risky to try alternate mylar replacement, especially regarding diaphragm streching.
Also, I think like you that some good DIY work on Sequel's and the latest clearspar panels will give a better result than a stock Ascent(for example).
Please, let us know the result of your investigations regarding woofers, I will share mine.
Ah, I forgot something, lucky guys you are: 550 dollars for a pair of brand new panels...that makes me dream! Here, in France, I had to pay 1230 euros, around 1580 dollars, for the same thing. The importator must be richer than me!

Bye
Raphaël.

 

[Eppo]

Hi,

Since only one panel got better by the shower, I also washed an old panel that I did not throw away after the last panel replacement, and this panel also sounds great now again!
I also cleaned the PCB's and all the contacts, and I glued one of the damping rings on the front of the woofer that had nearly come off. The good old Sequel II sound is back now!

But the bass is not the strongest point of this speaker, so I am very interested in an upgrade on this point. It is a good idea to share the results.

I live in the Netherlands, and here the price of replacement panels is 1250 EURO, like in France. Indeed someone is earning too much money. This is also a disadvantage for ML; if people consider to buy this speaker, they could get second thoughts.

Thanks for all your advice,

Eppo

 

[olive]

Hi Eppo,

I'm aslo searching for improving the bass of my Sequel and I think that an aluminium woofer like the Ascent i one should do the trick ;-)

By the way, are you working for ECT?
If yes, it means that we know each other :bowdown:

olivier
;-)