Another Amp / Impedance / Bi-amp question

[Mark F]

The only problem is that if they are worn out, your amp is going to be forced to work extra hard to drive them. I had bought a brand new Aragon amp and was unknowingly pushing it very hard all of the time. Having it set to +14 db all of the time. Whatever amp youre using, its having to work extra hard to obtain the same volume level that a new panel can achieve. Youre adding wear and tear on that amp. My Aragon did hold up, although I once blew a fuse on one channel, and it was then that I realized how hard I had been pushing it. Shortly after that I replaced those panels.
If you found both sets of serial numbers on the speakers, then youll know if those are the original panels. Its possible that the previous owner might have replaced them, and if they did then the serial number on the actual panel would reflect a different date than the speaker cabinet.

Serial numbers on panels and cabinets match. Panels are original on both used SL3s and my 25 year old Sequel IIs.

Posts discussing tired panels always seem to mention a drop in some particular frequency. Highs are soft. Voices are muted. Is it possible that all frequencies might drop off evenly such that speakers sound great but efficiency drops way off?

EAD PM1000 amp has no power meter or other indication of output so if it were consuming 100WPC to play background levels, it would not be obvious. Speakers do play concert levels but I have no way of knowing the power necessary to drive them to that level.

 

[Robert D]

Serial numbers on panels and cabinets match. Panels are original on both used SL3s and my 25 year old Sequel IIs.

Posts discussing tired panels always seem to mention a drop in some particular frequency. Highs are soft. Voices are muted. Is it possible that all frequencies might drop off evenly such that speakers sound great but efficiency drops way off?

EAD PM1000 amp has no power meter or other indication of output so if it were consuming 100WPC to play background levels, it would not be obvious. Speakers do play concert levels but I have no way of knowing the power necessary to drive them to that level.

Well, with my Prodigy speakers, if Audyssey was turned off, the woofers would overpower the panels and the overall sound was muffled and lacked treble. With Audyssey turned on, it would lower the volume of the woofers so that the panels were no longer overpowered. Since I had a nice BF 210 sub, the bass was still good. Audyssey adjusts the frequencies so that it sounds best and is balanced. I use a Marantz Atmos receiver that then has output to my Aragon amp. The Marantz I noticed had the front two channels turned up +14 db. Now with the new panels it is set at -2 db! So about 16 db difference in level, wow. With yours, im guessing youre using an integrated amp perhaps? Im guessing there is still a gain settings for those channels? Ive actually never used an integrated amp because I use my system for 2 channel music and as a home theater. It might be the only way you can tell if youre having to push your amp hard to drive the speakers is if the volume level is pretty high for the actual volume you are getting.

Perhaps someone else with more knowledge might be able to tell you to figure out how hard you are having to push your amps. I gave my old panels to Russ Knotts and he tested them, and he told me they were down about 14 db or so. Im not sure how he measured that. It matched what my receiver was set at after running Adyssey.

Id say that theres about 0% chance that your panels arent worn out now, but I could be wrong. Most on here agree that 20 years is about the max, if you use them all 20 years. Guys that put them in bags and just store them will have them last longer. Russ Knotts knows these speakers well, and if I remember right he said 20 years is about the max.

Some on here washed their panels. I was going to have Russ redo mine, but he said he didnt think he could separate the stators without damaging things. So i just ordered new panels from ML. Best $ I ever spent on audio. My Prodigy speakers were made in 2000. I bought them used back around 2018 I think. Kinda lost track of time.

 

[JonFo]

Is it possible that all frequencies might drop off evenly such that speakers sound great but efficiency drops way off?

Efficiency might drop if the diaphragm has deposits on it, such as oily water vapor getting on it, then dust sticking to that. One guy had a set where the left speaker was close to the kitchen, and after years, his set (SL3's IIRC) had a large level imbalance, with the left being much lower than the right.

The other way to tell if a panel is losing efficiency is if the balance with the bass driver tilts in favor of the low end.

However, the major issue is high-frequency roll-off if the panels are clean and simply old (like my 30-year-old Sequel IIs). Honestly, this is not a problem (in my case), as it matches the usual Audyssey roll-off.
So if you are happy with the sound now, you could defer the panel purchase. One usually comes out ahead by taking care of room acoustic issues first.

 

[JonFo]

Hi Jon, If I'm interpreting the thread correctly, the Crown XLS1002 provides includes an adjustable crossover and built in amplifier for a few hundred dollars? That would be a steal. You are correct that x-overs in Sequel are not ideal... muddiness on the lower end has always bothered me. Biamping and more power seem to help. It seems like the panel and woofer could be slightly out of phase with each other? The SL3s sound considerably better to my ear. Thanks for the link and tip on the Crown amp. Will read up on it a bit more and perhaps give it a try.

Yep, the XLS line is a fantastic bargain (especially lightly used or open box) for dealing with Gen1 ML ESL bass drivers and the inefficient and rather poor bass passive XO.
The phase relationship is indeed less than ideal with the factory passive, so an active XO will help clear that up. Getting a perfect match requires a full active setup like I use on my Monoliths, where impulses are aligned to the fraction of a millisecond.

Remember that using the active XO in the XLS requires bypassing the passive bass XO inside the speaker. This is easily done on an SL3: just pull off the panel with the terminals and power feed, cut the wires from the bass terminal to the XO, and use fresh wire and spades to wire up to the woofer (disconnecting the older feed). IIRC, the existing wires from the woofer to the XO were not long enough to connect to the terminals with the panel removed for access. But check, it might save some effort.

 

[Mark F]

Efficiency might drop if the diaphragm has deposits on it, such as oily water vapor getting on it, then dust sticking to that. One guy had a set where the left speaker was close to the kitchen, and after years, his set (SL3's IIRC) had a large level imbalance, with the left being much lower than the right.

The other way to tell if a panel is losing efficiency is if the balance with the bass driver tilts in favor of the low end.

However, the major issue is high-frequency roll-off if the panels are clean and simply old (like my 30-year-old Sequel IIs). Honestly, this is not a problem (in my case), as it matches the usual Audyssey roll-off.
So if you are happy with the sound now, you could defer the panel purchase. One usually comes out ahead by taking care of room acoustic issues first.

There are two pairs of panels to consider.
1. My 25+ year old Sequels IIs - I just changed amp wires back to these and they sound worse then the new-to-me SL3s. Highs are slightly muted, voices aren't quite as crisp and bass is slightly exaggerated. Unfortunately, these are the panels with no perforations, just 25 wonderful years of use. Vacuumed them (they have never been cleaned) and it helped a bit. May try the shower wash trick. Sequel IIs are positioned out of sunlight and our furnace has an electrostatic air filter which likely contributed to them going this long.
2. The new-to-me SL3s - By comparison, these have more detail and the bass is more balanced. The previous owner mentioned his cats damaged the panels while stored in his basement so they are newer, have improved crossovers and have seen less use.

Previous plan was to gift the SL3s with suitable amp to a good friend. Might need to re-think my generosity. Of course, the money-is-no-object solution is to purchase new panels for the Sequels and gift the SL3s to my buddy. Will wash my Sequel panels... hopefully that helps.

 

[Nuri58]

Wow, thanks for all the thoughtful replies! Given the many threads suggesting bi-wiring and bi-amping,

Bi-wiring is in reality just to put the binding post closer to the amp. The magic happens at the cross-over in both cases. You of couse need a cable twice a big.

Bi amning seems to make some sense to me for ELS as the low impedance is at the higher frequencies. At least for the ELS 9 and below.

 

[Mark F]

Bi-wiring is in reality just to put the binding post closer to the amp. The magic happens at the cross-over in both cases. You of couse need a cable twice a big.

Bi amning seems to make some sense to me for ELS as the low impedance is at the higher frequencies. At least for the ELS 9 and below.

 

[Mark F]

Yes. Group consensus seems to be that an amp which keeps its composure at low impedance is more important then bi-amping. Getting a 5 channel amp that is happy with low impedance loads (like Sunfire Cinema Grand 200x5 or similar) is best of both worlds if four of the channels can be devoted to main speakers.

My current EAD PM1000 amp is capable of 200x5 at 8 ohm and 375x4 at 4 ohms so is well suited. Will need another similar amp for new-to-me SL3s and Sunfire amps can drive low impedance loads, are readily available and are at the low end of the price range.

Since SL3s and amp will be gifted to a friend, keeping costs reasonable is preferred.

 

[Mark F]

Thanks for all the feedback and suggestions. A Sunfire Symphonic Reference 2x250 amp was purchased to drive the new-to-me SL3s and the combo sounds amazing. Incredible soundstage and detail. Its now clear why ML owners migrate towards Sunfire and/or other low impedance amps. This system will be given to a good friend. That's the good news.

The bad news is my legacy Sequel IIs with my EAD PM1000 amp sound like box speakers by comparison. A small part of it is the amp but ultimately its because the Sequel II panels are 29 years old with almost daily use. Funny part is that I was pretty happy with their sound until playing the newer SL3s.

Its now apparent why folks invest in new panels and have nothing but praise for the improvement. The exercise will end up costing me $1,400+ at some future date. Why waste money on frivolous things like food and housing when you can have new ML panels instead?

 

[Tmort]

I'd go for the Stereo Sunfire; it's a beast. I have three Sunfires, a Stereo, CG 5ch, CG Signature 5ch, and a Sanders ESL amp. The Sunfires are really good match for ELS.

If you want to bi-amp, I suggest going active bass crossover, as the XO in the Sequel II and SL3 is not that great and miles behind what a modern active XO can deliver. A Crown XLS1002 has built-in crossovers that can be set to match the passive XO and has gain controls so you can level-match to the panel. Many here have done that, and all rave about the significant improvement in the quality of the bass and mid-bass. See this thread: https://www.martinloganowners.com/threads/how-to-active-bass-section.19237/

How’s your Sanders amp in that mix? I’m considering the Magtech for my classic 9’s as an upgrade from Anthem MCA 225 mk2?

 

[JonFo]

How’s your Sanders amp in that mix? I’m considering the Magtech for my classic 9’s as an upgrade from Anthem MCA 225 mk2?

I love the Sanders, and will be replacing the Sunfires that drive panels with more Sanders amps. The Magtech would be an upgrade over the MCA line. The Sanders can deliver awesome amounts of amperage and voltage, and ESLs love that.

 

[Tmort]

I love the Sanders, and will be replacing the Sunfires that drive panels with more Sanders amps. The Magtech would be an upgrade over the MCA line. The Sanders can deliver awesome amounts of amperage and voltage, and ESLs love that.

Got one coming!

 

[Robert D]

Got one coming!

Let us know your thoughts in it once you've given it some time!

 

[Tmort]

So the Magtech is in and the results were shockingly impressive!
Roger Sanders clearly knows what he’s doing.
I believed I had clarity and good sound staging / imaging before, but upon listening to a couple of diverse tracts of music back to back with the Anthem amp the difference was profound, much more than I was expecting!
The clarity improved markedly which lead to an incredibly focused soundstage. It was so dramatic I had a quick “oh damn!” Moment with the pinpoint focus of a particular instrument that just wasn’t there with the Anthem. Beyond this, when driving the speakers to a loud volume the sound was effortless and not at all strained, a fact I quickly realized I’d been experiencing with the Anthrm amp.
Don’t get me wrong, the Anthrm had been doing a very decent job with the classic 9’s but obviously they weren’t getting the most of the panels.
This has been with the speakers bi-wired to the Magtech amp.
Next I’m going to try bi-amping using the Anthem for the bottom end and the Sanders Magtech for the panels (of course!).
Stay tuned!