CLS Built-In Equalization; A question

[risabet]

If you listen to any orchestral music, organ, synthesizer etc than a 40Hz limit is not low enough. The harp 30.9 Hz, contrabassoon 29.1Hz, the double bass 41.2 Hz all generate substantial infrasonic energy. Try Mahler, Saint-Saens, Durufle (organ) w/o the bottom octave. Maybe these aren't your cup of tea and if so great. If you only listen to guitar and flute more power to you, but the last concert I attended the basses generated palpable power even in the upper part of their range. Can you say infrasonics? I knew you could.

IMO the realistic reproduction of music in the home requires response to at least 30Hz and the best systems I've heard get down below 20Hz. I know there are few fundamentals (generally speaking) but the "power" of the orchestra is there. The Bosendorfer Imperial Grand is good down to 16 Hz, b-flat tuba to 25 Hz plus those mentioned above so there are instruments that generate bass below the 40 Hz limit other than the organ.

The only panel speakers I've heard that get down low with any authority are the big Apogees. Quads and CLS's don't come close to having adequate bass w/o subs but the best subs can be made to integrate nearly seamlessly with panels now.

The trade off IMS is between power and extension, i.e. I can get low bass to about 25Hz @ 85dB or higher volumes but not both. My 2 cents.

 

[IWalker]

HI Walker,
Thanks for you concern for my speakers but I am qualified to do the work in a professional manner (please read my response to Roberto). I have a much more capable electronics shop, including the necessary test equipment (all Tektronix), than is needed. What I do lack are the details of the equalization network. When I get to work, I should find the schematic of the network that Jim Powers sent me. My ISP's spam filter kept me from receiving the document at home.

I think I have not explained my current set up well enough to establish a starting point. Sorry, I thought it was clear but I can see that it was not. I have a pure bi-amped system. None of the amps or crossovers are built into the speakers. There are 2 signal paths that both originate at my preamp outputs. My ARC SP-11 preamp actually has multiple outputs, all with individual buffer amps so the destination loads don't interact with one another.

The CLS path goes from one preamp output to a home made passive hi pass filter (using MIT caps and very high quality Tiffany RCA's) to the D-250 power amp then to the CLS's. This is as simple as I could make it in order to not introduce the nasties caused by active filters and still have an adequate roll off. My goal is for the audio signal to be 5 dB (power) down at 35 Hz.

The other signal path goes from a completely separate preamp output to the Kinnergetics active crossover. I use only the low pass section. The crossover has several selections for filter type (Butterworth selected), slope (18 dB/octave selected) and cutoff frequency. The output of the active crossover drives the Levinson No. 23 power amp which in turn drives the dual subwoofers.

You are right when you say that my desire to alter the CLS equalization will cause a type of high pass crossover effect. If I could completely eliminate my home made high pass crossover by changing the CLS equalization I would do it. There are several reasons why this may not be possible from an electrical point of view. I need to know more. Hopefully, the schematic will answer some of these questions.

I think you have one misunderstanding and it’s important. My purpose is to increase the dynamic range of the panels in the low bass range, not sensitivity. Conceptually, these are two completely different things though it may appear they are the same. Minimizing the signal path, while desirable, is not the goal.

My original question in this thread was asking if anybody knows, for sure, if the CLS's had equalization built in for bass frequencies. This was speculation on my part. But knowing the cancellation effect, it seemed logical and necessary. If true, I had never heard of it before. Not in the specs, not in the reviews, not in the commentaries for any dipolar speaker. Since I am fairly well read on the subject, I found it odd that I had not seen it. Now, I believe it is not common knowledge. Really, if no one on this forum knows, except Roberto, who would? Well, bass equalization is now established as fact as my conversation with ML confirms. So, we can add this to our stock of interesting trivia. Hopefully, by manipulating the equalization, the performance of the speaker can be improved in a biamped subwoofer situation such as mine.

Sparky

Thanks for the clarification of your system. I was not questioning your ability...but merely the effect that the word *modified* might have on the resale value of the speaker...were you to ever decide to sell them. That's your call to make though.

Yes, I stand corrected on the dynamic range/sensitivity issue.

The only point I'll stay on is this: I would think it would be easier to modify your highpass to get you down 5db at 35Hz than to modify the CLS' to the same end...especially given that you seem to know the schematic of your high pass very well (as it is homemade), but haven't have access to the ML schematics.

I'm a tinkerer and love building and playing with things...so would be one to modify things just for the sake of "let's see what happens" so I'm not trying to convince you not to do it...just trying to present an alternative, and understand your thought process But yes, MLs boost the low end! If that's all you wanted to know, than it seems we can end the discussion here, as you got it straight from the horse's mouth.

 

[roberto]

If you listen to any orchestral music, organ, synthesizer etc than a 40Hz limit is not low enough. The harp 30.9 Hz, contrabassoon 29.1Hz, the double bass 41.2 Hz all generate substantial infrasonic energy. Try Mahler, Saint-Saens, Durufle (organ) w/o the bottom octave. Maybe these aren't your cup of tea and if so great. If you only listen to guitar and flute more power to you, but the last concert I attended the basses generated palpable power even in the upper part of their range. Can you say infrasonics? I knew you could.

IMO the realistic reproduction of music in the home requires response to at least 30Hz and the best systems I've heard get down below 20Hz. I know there are few fundamentals (generally speaking) but the "power" of the orchestra is there. The Bosendorfer Imperial Grand is good down to 16 Hz, b-flat tuba to 25 Hz plus those mentioned above so there are instruments that generate bass below the 40 Hz limit other than the organ.

The only panel speakers I've heard that get down low with any authority are the big Apogees. Quads and CLS's don't come close to having adequate bass w/o subs but the best subs can be made to integrate nearly seamlessly with panels now.

The trade off IMS is between power and extension, i.e. I can get low bass to about 25Hz @ 85dB or higher volumes but not both. My 2 cents.

Hola Risabet...yes, I understand that there are some instruments that have a lot of bass, but tell me how many notes are played when listening that go that deep. Usually at the works music for them, you don´t find that notes, the deepest ones. I am not saying also that the CLSs are the best at low frequency...my point is that most these heavy bass notes are above 45Hz, because also, these notes are very difficult to sound even through the instrument itself...most of them at very low (except the organ) frequencies have a drop in intensity due to the difficult to reproduce them...yes I do understand the infrasonic octaves too. If you read the specs of the CLSs they are capable to reproduce +-2 dBs from 35Hz to 20Khz. If you set them right, specially in a small room, the CLS are very good on bass too. I love bass, but usually we have too much energy in our rooms...it is just my liking. I do respect all of you that like deep bass energy is your rooms...my point is that when you have these deep notes, the stage gets smaller and puts you near that instrument for just a moment...listen to live symphonic music and tell me if you get these bass energy as we do with the subs in our rooms, usually we have too much. The bass energy in a symphonic is there, deep and with a dynamic that still is the challenge for any sound system. But is with the orchestra...not next to you...I am sorry that I can not explain myself better with these points...the good thing guys, is that we do enjoy our systems very much, and we can talk regarding how we got the results to enjoy the musician(s) in our own room. Happy listening,
Roberto.

 

[karma]

But yes, MLs boost the low end! If that's all you wanted to know, than it seems we can end the discussion here, as you got it straight from the horse's mouth.

HI Walker, Roberto and risabet,
Walker, yes my original question is answered and if I come up with positive results I will let you all know. Thanks all.

I don't mean to cut this discussion off. Keep it coming.

Sparky

 

[JonFo]

no substitute for displacement

The CLS extension into the bass region is pretty good, but as others have alluded to, what’s critical is the power curve.

That is, can they maintain 105 SPL at 40Hz?

Since they can play at that level with frequencies above 200Hz, then it stands to reason that a non-linear power curve in the bass is not a good thing.

Now sometimes the room gains compensate enough to bring it back into range, but generally, the answer is they do not.
The issue with power curves is one of the critical aspects of integration of various components come into play, whether it’s matting a sub to a set of dynamic speakers or to an electrostat.

Since low frequencies require moving lots of air to obtain high SPL, the total displacement (measured in cubic liters) is critical.
Therefore, let’s do some math:

A CLS panel is 24X48 inches or 8 square feet or 2.438 Sq Meters of radiating surface (per side).
Assuming a z-axis displacement of 2mm (more than that and it touches the stators) we get a total volumetric displacement of 0.49 liters.
Doubling up due to the panel having two radiating surfaces (albeit, out of phase) we get a tad less than a liter of displacement per panel.

Two CLS’s in a room will then displace roughly 2 liters of air at max excursion.
Now half of that displacement is indeed out of phase and will cancel as noted above. But let’s ignore that fact for now.

Compared to a decent sub, say a 15” or even a mighty 18” Velodyne, which has 2.15 liters of displacement, the CLS is in the ballpark for total displacement, however, that out-of phase stuff will catch up with ya and reduce the effective output of all that displacement.
I’m not quite sure what factor to apply for out of phase cancellation, but lets be generous and say it only costs 25%. Therefore, we now have 1.5 liters for the sum of both speakers.

Therefore, while a CLS can provide decent bass, it will not be able to maintain it at high SPL as compression and displacement limits will kick in.

If one applies a more realistic cancelation factor of 75%, then total displacement is barely above a liter or so. Which means there is no way its bass is as good as its upper frequencies.

As a point of comparison, I had two Velodyne 18’s (4.3 liters total displacement for both) in my room and they were not able to keep up with the Monoliths. I built an Infinite baffle sub (4x15” drivers) with a displacement of 15.24 liters and now I have enough bass to keep up with the Logans all the way out to 110DB at 30hz.
It still maintains 105DB at 20hz (or lower, but can’t measure accurately down there).

Bottom line, it takes a lot of displacement to produce high SPL of low frequency acoustic energy, either you have it or you don’t.

Other low frequency radiator integration aspects apply to makes this a success, but that’s a whole ‘nother thread ;-)

 

[Chuck Lee]

CLS built in eq

Try doubling up on the CLS. I place mine side by side.You will still have the sound of a single coherent CLS with the added radiated area of the extra panels and that means more bass will be provided. More bass in this case is not deeper,or louder bass, just more bass than with 2 panels.Sub woofers with the CLS are a mixed bag and those who support their use with the CLS are hearing more bass for sure. It is just not CLS bass,it is not cut from the same sonic cloth.Double pairs of CLS require nothing more than the extra room size, and an extra bit of cabling. In my set up I use 3- three foot single runs of solid core wire per speaker.This set up solves many of the short-comings associated with the CLS run without a sub. It certainly solves all the problems of running the CLS with a sub.

 

[DTB300]

HI DTB,
What is your problem? Are you trying to make this confrontational? Well, I'm not going to bite.

Problem??? I am being confrontational??? Chill out. And stop tryin to spin it back the other way.

I asked a question to explain your statement, and you did not answer it I will make it easy and post again:

"And BTW, real musicians on stage and great bass are not mutually exclusive"

No need to feel threatened as you seem to be....Just an explaination for the post. Yes, you were replying to Roberto, but such a statement needs further detail rather than just blurting it out.

BTW, you are doing a good job yourself at being confrontational. Telling people that their musical preferences are wrong, their opinions and statement futile, bringing "God" into explainations . Then, it wasn't enough with this thread, so you decided to start another thread, basically talking about the same thing....again.

Take a breath Pal.....and settle down. All of us here respect each others opinion on what we like and do not like, and we do not go around slamming each other for our preferences. If this is your way, and your ego is so large that only you are right, then this is not the place to be.

 

[risabet]

Hola Risabet...yes, I understand that there are some instruments that have a lot of bass, but tell me how many notes are played when listening that go that deep. Usually at the works music for them, you don´t find that notes, the deepest ones. I am not saying also that the CLSs are the best at low frequency...my point is that most these heavy bass notes are above 45Hz, because also, these notes are very difficult to sound even through the instrument itself...most of them at very low (except the organ) frequencies have a drop in intensity due to the difficult to reproduce them...yes I do understand the infrasonic octaves too. If you read the specs of the CLSs they are capable to reproduce +-2 dBs from 35Hz to 20Khz. If you set them right, specially in a small room, the CLS are very good on bass too. I love bass, but usually we have too much energy in our rooms...it is just my liking. I do respect all of you that like deep bass energy is your rooms...my point is that when you have these deep notes, the stage gets smaller and puts you near that instrument for just a moment...listen to live symphonic music and tell me if you get these bass energy as we do with the subs in our rooms, usually we have too much. The bass energy in a symphonic is there, deep and with a dynamic that still is the challenge for any sound system. But is with the orchestra...not next to you...I am sorry that I can not explain myself better with these points...the good thing guys, is that we do enjoy our systems very much, and we can talk regarding how we got the results to enjoy the musician(s) in our own room. Happy listening,
Roberto.

Roberto,

Come on, those specs are great in an anechoic chamber but in an actual room I doubt that CLS's will make 45Hz +-5dB and more - than + IMO due to dipole cancellation.

Yes, most of the instruments I listed are rarely used at their low end extreme. Mahler did regularly use the low end of the CB, but yes I agree that they are not often used. Where we diverge is in the idea that the infrasonics of all the orchestral power instruments demand reproduction to mimic, poorly I admit, the emotional impact of a real orchestra (laughing at the idea, actually). That won't happen with panels of reasonable size w/o woofers.

I think I understand what you are saying about the bass being with the orchestra and not next to you. In real life the bass forms an integrated whole with the music. Bass instruments are still specifically located but their power is integrated into the soundfield of the orchestra. You can't get that integration.

 

[roberto]

Roberto,

Come on, those specs are great in an anechoic chamber but in an actual room I doubt that CLS's will make 45Hz +-5dB and more - than + IMO due to dipole cancellation.

Yes, most of the instruments I listed are rarely used at their low end extreme. Mahler did regularly use the low end of the CB, but yes I agree that they are not often used. Where we diverge is in the idea that the infrasonics of all the orchestral power instruments demand reproduction to mimic, poorly I admit, the emotional impact of a real orchestra (laughing at the idea, actually). That won't happen with panels of reasonable size w/o woofers.

I think I understand what you are saying about the bass being with the orchestra and not next to you. In real life the bass forms an integrated whole with the music. Bass instruments are still specifically located but their power is integrated into the soundfield of the orchestra. You can't get that integration.

Risabet...agreed 100% with you too. And of course I do know that my CLSs are very bass shy if I compare them to cone speakers...but I rather have this than big bass energy in my room, making this to loose all what I had worked to get a stady stage and right size with the instruments. Of course I know that the bass infrasonic fundamentals are needed...I had a Pevey Sound Pressure Level Meter once, and I took it to our National Theatre. There I messure only 93 dBs at the higher passages of the music (Mahler No. 2) and I was in the third rod, only about 10m away of the musicians!...but live music is so different than the one that we play thorugh our systems. Also this is my liking...the stage, the soul of the musician(s) almost every note. I think it really is a matter of taste. I don´t see or find any harm if you (ML Lovers) like bass in your room, and I do know that many of you prefer the energy than what I like. It is ok my friend...and thank you so much for your recomendations...you are a very dedicated person to your sound Risabet!...it is a honor to be with you guys, where we can share our experiences in our beloved hobby...listening to music through the greatest ML sound on mother earth!!! Happy listening,
R.

 

[lugano]

For me, all this is a non-issue. I don't need no separate crossovers. I don't need no tweaking my CLS. All I need is a sub connected to the power amp's posts, a sub that knows what to keep and what to discard. The CLS gets the full enchilada, the sub too, and I tell him via 3 pots what to do - where to start listening, where to stop and how loud he must yell out what he gets. Full stop. And the whole works perfectly.

 

[karma]

HI lugano,
The secret is the enchilada. I prefer red.

Sparky