Q1: amp that does not like bellow 2 ohm impedance Q2: LF driver of the Monolith III

[TheHun]

Hello All,
I'm new to the site so apologies if I'm bringing up what has already been discussed.

I have a Monolith III for a couple of years now (active xover, non-balanced). Panels have been changed approx 2 years ago – a move that persuaded me that it wasn’t my ear failing me after all, and removing artifacts and obstacles from around my eardrum was in fact successful.

When I have become a family man with all it’s effects on one’s budget and priorities I did have to stop improving my musical system but now I’m back on.

NB: Although Jim Powers personally was really veeeery helpful (thanks again) in answering my recent distress signal - when my 4 years old daughter has rubbed some chalk in the panels as an Easter present - I would not want to bother him with all this sort of questions.

So to cut the long story short;
Q1: Do I take a small or important risk buying a class A 40W/ch amp that does not like impedance loads bellow 2 ohms?
I’d like to buy an A class amplifier, fairly decently rated 40W/ch in class A mode, approx 120 W/ch in AB. That would, I’d assume, sufficient for the purpose, but the manufacturer (Etalon Acoustics) said I’d better ask if the panels do go bellow 2 ohms in any frequency. Of course it will drive it fine at low to normal levels (which is the way I use it) but the wide dynamic range of a grand orchestra can kick back heavily in a crescendo, for example.

The amp works with a wide frequency range, and to my knowledge electrostatics do go bellow the 2 ohm impedance, but I’d like to ask your opinion with such amps.

Is it risky or not so?

Note: The cases it that the beefy US amplifiers do not make it often to the old continent and whenever something (heavy) crosses the ocean it’s price performance ratio usually drops drastically anyways, so we have to cook with what we find locally.

Q2: Is there a point in replacing the low freq driver of the Monolith – from which one is not the original anyways? Does it significantly add to the handling low frequencies? With what dirver, if any?

Thanks in advance for any feedback.

 

[Kruppy]

TheHun,
First off, welcome. I believe you are the second member from Hungry. Ungaro, being the other member, is in Budapest.

JonFo is the resident Monolith expert. I would search the site for his posts. You should be able to find quite a bit of Monolith information that he has posted. He has replaced his drivers with very positive results, but his system is very "special" (and I mean that in a very positive way).

 

[johnwa]

I was going to suggest the same thing as Kruppy as JonFo has instructions on the site on how to replace the drivers and has helped me dial in more bass from my Monolith III's with the same active XO as you. He really is the source.

 

[JonFo]

TheHun,

:welcome: to our club, great to see more and more international participation.

To your first question, I’d be careful with any amp that was warnings about low impedance abilities, as the actively crossed-over Monolith panel is essentially presenting the raw impedance of the transformer and panel together to the amp (no passive resistors or caps to increase impedance somewhat as in other units).
I believe it goes to just slightly below 2ohms at the highest frequencies. It’s not quite as bad as the original CLS, but close.

My recommendation is to find a Sunfire amp and try that first. As they are able to handle the very low impedance curve with absolutely no problem. They pass plenty of current, which is what’s needed here. Also, they are very lightweight for their ratings, and since they need very little heat dissipation, they are not weighed down by heatsinks either.
The question is are there 240v version available in your country?

Another European amp I’d recommend is the TacT Millennium. Not cheap, but also able to deliver the required current.

As for the woofer, my recommendation is to update it. Links to that are in my system description.

Kruppy, JohnWA, thanks for the kind words.

 

[TheHun]

Dear Kruppy and Johnwa,

Thank You very much for your kind and quick response to my question. I had already looked and found a lot of useful information concerning the sub replacement in JonFo’s posts, not to mention the thrilling pictures of his system. (Holy watts and waves, call that commitment!) :bowdown:

Dear Jonathan,
I really appreciate your response concerning the topic as well as the welcome sign; it’s good to meet the community!

For the amp: Sunfire’s are rare; apart from a few subs and a receiver I haven’t found a trace of them. I’m looking at a TacT now, but yes, the price is a bit out of reach. I’ll see what I can make out of it. I can feel that it’ll be a longer process.

For the sub; I’ve been looking for the replacement sub, and I have found the Peerless 830669 model you have used. The price is really a bargain but I was wondering that there are also a number of other similar sized Peerless drivers that are claimed to be, let’s say, more elaborate according to their price.

Manufacturer Description ID USD/pc
Peerless Coated paper cone AL shorting ring in magnet system 830669 75
Peerless Coated paper cone, 76 mm voice coil 830867 210
Peerless long stroke woofer with die-cast basket 830500 200
Peerless long stroke woofer with die-cast basket 830845 205
ETON Hexacone 12” 500 + wow
(eh, I have a feeling that my table is going to look crappy...)

Since, judging by the measurement pics on the posts you have had a professional approach to the replacement of the driver I was wondering what was the reason for not selecting a somewhat more expensive driver.
It wouldn’t have given more for the bucks? Or even less?
Or apparently the 830669 has the lightest moving mass, so probably gives the best controlled bass?
(Though I must admit I did not check the obvious yet; what fits in the place of the original?)
Thanks again,
Miklos

 

[JonFo]

...
Since, judging by the measurement pics on the posts you have had a professional approach to the replacement of the driver I was wondering what was the reason for not selecting a somewhat more expensive driver.
It wouldn’t have given more for the bucks? Or even less?
Or apparently the 830669 has the lightest moving mass, so probably gives the best controlled bass?
(Though I must admit I did not check the obvious yet; what fits in the place of the original?)
Thanks again,
Miklos

Miklos,

Cost was not a constraint, I actually looked at some >$500 units from the Netherlands. But correct frequency response, low mid-bass distortion and of course fit for the volume we have in this box were.

Remember that my goal was a driver that could play clean well past 500Hz, and I moved my crossover from 125Hz up to 315Hz (and doubled the slope of the X-over as well to LR 24db/octave).Also, that I cross over to my sub at 60Hz (again 4th order X-over).

Most 12” drivers out here assume you have decent mid-bass already (some 7” driver in a three-way) and don’t attempt to go high. They are all competing on how low the can go and compromise on the upper bass range.
For my application, I wanted the lowest mass driver, which the 830669 is (recheck the specs, it’s half of what the 830867 is).

The results are quite good, not perfect, but very good. And definitely a huge improvement over what was there before in terms of mid-bass support.
In many ways, a higher quality 10” driver would probably be a better choice, but that would entail more wood-working than I was up for.

If you cross over to the sub at 60Hz or so, then this should be a good driver and the cost is pretty friendly

 

[TheHun]

Hello Jonathan,

Thanks again for the very helpful info. Sincere appreciations, really.
Somehow I missed the change of crossover point; the choice is clear enough now.
Since I think I do not yet want to venture into changing the crossover unit which I guess is required to change the crossover point, so I’ll reconsider the issue. :meditate: Still, I think, replacing the woofer will serve the Monos right.

For the amp, strangely enough I have found a Tact Millennium at an acceptable price. Incredible but I’m realizing right now that since - as I understand - it is a digital amp, I do not know how would I stick it in the system?
1) After the x-over? Not really, I’d also need another colossally priced unit to accept analog source.
2) Replace the DAC + preamp and use the analogue output to feed the x-over for the woofer? OK, but how do I prevent the sub 125 Hz going to the panels?

Ah, sorry for posing so many questions and concerns; that is what happens to me when I feel like getting back to upgrading the system… :banghead:

Thanks and have a nice WE to all!
Miklos

PS: I did have a problem that the grounding on one of the ICs going to one woofer was slight loose and the amp did throw the 50 Hz at the bass driver with different intensity (at one point so loud that I considered wetting my trousers). I was looking for the problem for a while until I found it! Ah, this is the sunny side of having 5 equipment + 5 cables within the signal path. (An as I can see this is simple considered to what some people have.

Soo, I have re-checked the cables and the amps with some pro help and I reassemble the system during the weekend. Yes, yes, yes! :musicnote:

 

[JonFo]

...
Somehow I missed the change of crossover point; the choice is clear enough now.
Since I think I do not yet want to venture into changing the crossover unit which I guess is required to change the crossover point, so I’ll reconsider the issue. :meditate: Still, I think, replacing the woofer will serve the Monos right.

As I noted in my woofer update thread, of the suitable drivers there is a great choice for your needs, the AudioTechnology Flexunits model.

The Flexunits seems like a good choice if you do not use a sub, as it has better LF response and a better motor. However, it’s more expensive and does not quite go as high as the Peerless, but definitely goes high enough for the factory x-over points or even higher. This one should be plug and play and easily available in Europe (as it’s a Danish company).
I still recommend using a sub and crossing over between 40 and 60Hz. It adds complexity to integration, but results are quite worth it.

...
For the amp, strangely enough I have found a Tact Millennium at an acceptable price. Incredible but I’m realizing right now that since - as I understand - it is a digital amp, I do not know how would I stick it in the system?
1) After the x-over? Not really, I’d also need another colossally priced unit to accept analog source.

Oops, sorry, big fan of all TacT items, so I forgot that it’s normally used with a TacT front-end. An RCS 2.2x will do both room correction and crossover, but the cost and setup complexity starts spiraling.

Forget this path unless you want a lot of changes. Results would be great, but, the Euro’s spent would be as well …

Just look for a nice Analog amp, a Plinus or something. Plenty of amp recommendations on the board.

For the woofer amp, don’t go overboard. Any decent amp with >100 Wpch will do. It’s the panel that takes special care to get right.

Yep, active systems tend to incur complexity, but the payoff is worth it.

 

[TheHun]

Well, this TacT solution got my imagination going. (And I mean galloping; when you are rolling in the bed late at night sleeplessly, thinking on how to go on, taking into account different solutions and their promises; phewww. I have heard the Magic Flute from Mozart (oh, God, that IS a long piece) in the opera, and I was just wondering how many tickets would I be able to buy from the bucks I have spent on the equipment. And how far is almost any system what I heard from the live sound. OK, it’s not a good comparison, since it would be kinda impolite to sit down in shorts, having a beer or glass of wine with the feet on the seats of the next row in the opera. Not to mention to ask the musicians to switch from Mozart to a mellow jazzy tone or call Steve Tyler on the stage just cause I feel like it.)
Anyhow, I let go of the Millennium MK1 opportunity, but looking at the Lyngdorf homepage and reading about the Millennium I have found the TDAI 2200. It seems to be the big bang chez Lyngdorf (4450 USD?) with the optional RoomPerfect module (a whopping 2300 USD for a rather small circuit board). However, people apparently say it does some magik.
I’ll still have to do some calculus to persuade myself. I do not even try to persuade my wife. Just try to sneak in with the amp…

At this stage I have reconnected my existing amps, and I must say that I’m far from happy; the hummmm is gone, but there is still some kind of noise clearly audible on the panels, and though resolution appears to be good, I have practically not spatial extension. I have a L / R channel test and indeed I’m listening to stereo, but space is nearly non existent. I dunno what has happened. The speakers are fairly close to each other, ~4 feet between their inner sides, but at least from near field it should be better then what I get now. It used to be anyhow.

So I need to start checking the components for the noise first; I’ll replace them one by one to see who’s cheating. I’m wondering if placing the x-over directly on the power amp is a good or not so good idea. Anyhow, all these components with all their own (sometimes twisted) personality and deviations are pushing me towards the Lyngdorf solution … Then, I could go as well be playing with the x-over frequency and how it’d affect the low end fidelity and go for a better bass driver. Living room has a stupid shape as well. Hmmm.
I have a feeling that I’ll succeed in persuading myself to the TDAI 2200, at least for a demo.

OK, sorry. Just some last advices;
Behind the ML’s I have a plane plastered brick wall; they are about 1,5 – 2 feet from the back wall. I’m looking at member’s systems but I do not see that anyone would actually put a carpet behind to prevent sound reflecting back from the wall. Does it help in any way or not really?

Jonathan, thanks again for your ideas!

 

[TheHun]

hey my room is in for a treatment

Well hello again to everybody who might read this post.

I left off this thread somewhat unhappy :think:, lamenting over a Lyngdorf (TDAI 2200) amp with the room correction system. Since I consider it as a major investment, I have decided to give my living room acoustics a chance and ask for pro advice to improve it.

The really nice fellow who built the DAC that I’m using (and who also makes room acoustics elements) came equipped with a PC, mike and some software to objectively and more important with his ears to subjectively evaluate the system and environment.

We started off by pulling the MLs out from approx. 2 feet from the back wall to about 3.5 feet (1/5th of the length of the room), also pushed them apart from about 4 feet to 5 (distance between the inner part of the bracket).
Then we started measuring the frequency response. He said that in the upper region it was one of the best that he’d seen , really within a few dbs of fluctuations.
Yeah, 5 points to the Monolith panels!
After pulling the MLs from the back wall the lower frequency response was not so bad (in the listening position) then what I have expected, but since I’m still planning to change the LF driver so we did not go much further. I’ll get some tube traps from him to experiment with.

However, the reflections from the back wall (plane plastered, painted 5” thick (or thin) brick wall) were not helping out with the image, so we did place three diffusors (approx 2x3.3 feet) behind the two panels and in the middle. It really helped to clear up the image and vocals.
Hey an improvement again. Now they start to sing like I expect them to.

Well after all we still have some time left till the ganb-gib and it appears that life ain’t such a putty, so let’s enjoy it! We fired up foobar and invited some singers and orchestra on the stage. Yeah, there they were!:musicnote:

Only drawback is that I can’t leave the speakers pulled to the front; my daughter would certainly find it amusing to play hide and seek behind or “catch me if you can” around them. Nor do I want to lift/pull them to their position every time I’d like to listen to music, so the next project is to construct a stand with rolling feet (I wonder what is the proper name for that) to pull them in and out more easily when needed. OK, it is a compromise, but better then either MLs stuffed to the wall or family running over them.

There is a recent thread about how much endorphin do you get from your 2 channels. My system has just climbed on my subjective scale from 6 to 7. Yep, yep.

So, to conclude it so far, I have experienced the meaning of what people - who went all through this - keep sermonizing in forums; room treatment and positioning; try it before using snake oil and hopelessly changing your components. You might end up happy.

I’ll keep you posted with the news…

 

[MotorToad]

GREAT NEWS! Glad to hear you're making progress.

If it makes you feel any better, at the moment I'm facing trying to make improvements to what might be the worst acoustic room I've ever been in. My friend who is adopting my older equipment (mid-fi at best to most here but some fine stuff IMO!) just bought a house and the listening room is HUGE, asymmetrical, vaulted ceilings, with hardwood floors and no curtains. . . . And his wife has the worst WAF factor I've ever seen, she's absolutely nuts and thinks that I'm an idiot for suggesting ways to improve the sound.

I would rant... but I think I'll just start another thread. I need help with artful room treatments. Good luck with your room!

BTW, this is far from helpful, but wheels are the worst way to couple a speaker to the ground. Certainly it's a lot better than having the speakers too close to the wall, but it's a poor mount for something that moves as much air as your speakers do. I wonder if I could make any money selling a spike system that has wheels that only touch when the speaker's tilted so you can roll it and it sits properly when upright.... (TM) MotorToad!

 

[kwr]

Only drawback is that I can’t leave the speakers pulled to the front; my daughter would certainly find it amusing to play hide and seek behind or “catch me if you can” around them. Nor do I want to lift/pull them to their position every time I’d like to listen to music, so the next project is to construct a stand with rolling feet (I wonder what is the proper name for that) to pull them in and out more easily when needed. OK, it is a compromise, but better then either MLs stuffed to the wall or family running over them.

...they are called casters - been there done that

BTW, this is far from helpful, but wheels are the worst way to couple a speaker to the ground. Certainly it's a lot better than having the speakers too close to the wall, but it's a poor mount for something that moves as much air as your speakers do.

I do agree but the improvement obtained by getting the speaker away from the wall is far greater than putting the speaker on to spikes. With family considerations it seems a good thing to do.

Kevin

 

[TheHun]

So the next act unfolds as I had some friends coming over to give their verdicts

First of all:
MotorToad and Kevin, thanks a lot for your comments!

Since I’m still taken by the drift to improve my system I have invited over a former colleague and his friend to listen and comment it. I did not know that he is / they are quite involved in tweaking / building audiophile equipments.

I’d like to highlight in advance, that they did not came to sell anything; they came with some good ideas and brought some good stuff with them; I think they were just as curious to hear the Monolith IIIs (majestic, but not a very common beast in these realms) as I was curious about their subjective judgment.

Apart from the placement and tweaking ideas they also came with two absorbers, a few granite plates, a set of (3) equipment support feet, two interconnects, a passive preamp and DIY DAC (1541 based).

I have a Marantz DV 9500 lent by a colleague so we let it start the show and listened to music on the system as it is today. We did not have a lot of time (3 hours) so we played a disc or two they know and some that I do to be able to compare differences.

I do hear that different equipment sound different; some fit more to my taste and others less. Same with cables; I know it is a delicate matter, but in my system different cables do sound different. I have 4 interconnects and two set of speaker cables. We have changed one (source to preamp) and the sound changed; improved.
I do hear the difference with room acoustic elements placed behind the speakers. Absorbers were more convincing then diffusors in my case.
I did not very much believe in placing special equipment support feet (under) or heavy granite plates (under / over) the equipments. To my surprise it did improve sound when we put the feet under the DV 9500 and the granite plate on top.
Yes, probably with a good equipment stand the returns of such extras are diminishing, but its working in my present system.

Then we changed the interconnect running from the source to the preamp. More detail, more precise spatial positioning. Then the same IC from the preamp to the active xover. The first IC replacement had a more defined effect.
Then came the passive preamp. Ouch, I thought of my preamp as being transparent. Well, the term has been redefined by a deceptively small box…
Next the DAC. It is not a very recent design but I’m afraid it did beat my locally made DAC as well as the DV 9500. Refined, excellent, articulated bass and other improvements.

We had a dinner and had time to listen to some music without switching equipments. That’s the goal after all. I’d say that if the last time my subjective scaled climbed from 6 to 7, today it has hit the 8 mark or even above that.

I ask myself; did I want to hear the difference?
I do not think so; I did not have any motivation to actually want to hear it. We tried to keep the listening level more or less constant. I did not buy or wanted to buy anything, nor do I fall for the pressure to hear the difference just because somebody else says so. (not as if this would have been the case). I just simply heard it. It is especially evident when switching back to the less capable equipments.
Also, I was not in case of each modification very clearly convinced if the difference meant improvement or if it was just different, but in general the changes did improve the sound.
So what did I hear? More detail, better imaging, more believable vocals, more defined bass, more focused instruments and vocals - the balloon sitting on the neck of the singer turned out to be her head - to name the most important ones.

Life ain’t easy; I can see that I’ll upgrade but while I was rather desperate to take the digital path and room correction with Lyngdorf (TDAI 2200), I can see that there are other ways to musical nirvana.

I did not write any brand name yet as these were all made or assembled by these guys and the products do not have a name yet. Well they do but it's neither published nor commercially available.
I can just hope that they will make it to being able to commercializing their intellectual assets one day.

Why did I write this down? I dunno. If you have got this far, it was not entirely useless.
OK, if I think it over, I guess I wrote all this down, because I was really discouraged by investing in a system and then getting a good-for-nothing (OK, bit of exaggeration there) sound. My relation with the different equipments of my system is somewhat bumpy. I purchased most of them on auctions and via private ads at 30-40% of their original price hoping that used hifi can still be good hifi. Some were good and some others weren’t but if I add up, time, effort and money, I would have expected something that I can live with happily (almost) ever after.
And when I finally (pretended to) have the time to put it all together; boooo, I’m disappointed by what I hear. Messy, narrow, undefined soundstage, unconvincing vocals, muddy bass. That was about when I started this thread.
I can see that it’s happening with one of my present colleagues (who bought and lent me the DV 9500 because he thinks that he bought a piece of goo and wanted some reassurance that it’s not so crappy after all) and I think it’s not the path to take all alone and I’m trying to help him.
Today, I’m a lot happier with the mods (room acoustic elements, placement) and the possibilities (preamp, DAC, cable) that confirmedly make the system worth the efforts and I think I just wanted to share this with others who might, one day, be in a similar situation.

Heads up, hope ain’t lost yet.

 

[sebrof2000]

Thanks for sharing.
I think we're all looking for ways to improve the sound of our systems, so reading about other people's trials and errors is always helpful. Someone might list 10 things they did, and out of that I might do 1 thing that really improves the sound...or not But, hey, that's what it's all about, trying different things, playing around. To me, it's a hobby. The path is the thing, not the destination.
It sounds like you heard enough in the short time to pursue some options. Good Luck!