Single-ended triode amps

[acg]

Mani,

Lovely looking speakers and I think there is a lot to like about the design of them also.  I would be so tempted to go active with them, but to each their own of course.  Are you planning a sub at all?  You get so much "presence" with the lowest octave...personally I would try to integrate a lower channel (says he not having heard them - sorry!)

Cheers,

Anthony

[manisandher]

Hi Anthony, no... no changes planned whatsoever.

I've totally fallen in love with the SET sound, top to bottom, and going fully active would mean 3-4 SET monos on each channel. I'm simply not going to do this. And I'm not in the least bit interested in any other type of amplification now, so no mixing class-D (or whatever) for the bass, and SETs above. For me, it's got to be SET all the way.

I now hear a 'glare' / a 'sheen' that all the PP amps I have here seem to add to the sound. It sounds really impressive for a few minutes, and then fatiguing. The sound is too 'tight', too controlled almost. Actually, I'd say that the only PP amps I've ever heard that don't have this were the Sauermann monos I owned. I don't regret selling them though, because as good as they were, I still prefer the sound of my current (cheaper) SETs.

I reckon I'm getting a good response down beyond 40Hz (with a big dip at 50Hz still). That's good enough for me.

Mani.

[Scroobius]

I just wanted to give my impressions of Mani's sound with Orelo's as I have heard his system many times.  The sound of Mani's Orelo system was almost diametrically opposite to mine (essentially the same system as Mani's). In fact if blind folded anyone listening would have said they were totally different systems with maybe some very small similarities. Not only was the bass completely and totally different (that has been discussed many times) but just about every other aspect was different. The dynamics and "alive" quality of the sound here is similar to a live performance. Bass is simply amazing on live recordings, you can "feel" the stage moving on some recordings (Brubeck Time Further Out for example). From bass through mid range to top end totally different sound. It is inconceivable that it would have been possible to have made tweaks or even radical changes to Mani's system to have made the sound anything like mine.

This is absolutely not a boast, it is simply an observation and I regularly thank the almighty for gifting me the acoustics in my room. BUT I am sure that it was an accident and I am equally sure the almighty did not intend to do any such thing. That is because my room is an ABSOLUTE DOG and would be written off by any self respecting sound engineer as a ridiculous place to even attempt to reproduce music.

As an example with music playing walk the length of my room away from speakers toward the listening position and you will hear cancellations and reinforcements in the bass as you walk. Not just trivial small changes but wapping great big changes.

I have also heard Peter's system and it just does not happen at his which is in a very big room with lots of space between the outer edges of the speakers and the side walls. No such luck here there are lots of side wall reflections because so close.

So here are some quotes from Mani's and Peter's posts above: -

Orelos need a couple of meters of breathing space......

.....how else is it working out elsewhere, including my own room (say 80cm from the wall behind them)

........but which means that it comes to you without too many (early) reflections, especially not from the back.

Peter is (of course) absolutely right the Orelo's reduce rear firing bass. And I have measured that here - over much of the bass frequencies. But certainly not all. Lets take 50hz, in this room a very strange thing happens. Measured inside the throat close to the speakers of the Orelino's the response is very even measured 20 to 200 Hz. But move the microphone out of the throat of the speaker to the interface where the sound leaves the speaker and hits the room and a very strange thing happens. There is an almost total cancellation at 50hz. In the measured response there is a deep notch at 50Hz all around the listening space. If I play a test tone of 50hz and then walk all the way to the listening position you virtually cannot hear it at all. So where does the 50hz go? well the answer is that because it is not being cancelled by the forward going 50hz wave it travels backwards into the conservatory that is behind my speakers. If you stand in the conservatory right at the back whilst the speakers are playing you will find it almost painful to hear. You would not guess it by listening but it does appear to be a small range around 50hz.  There is a lot of sound energy travelling backwards from my speakers IN THIS PARTICULAR ROOM and that is proved by measurement and from the fact no one wants to sit in the conservatory while the speakers are playing  .

So the acoustics in my room are very far from ideal but you would never think it when you listen. The sound quality according to every one who has listened to them is simply astonishing. I really cannot imagine what it will sound like when the B'ASS and Phisolator mods are applied - my mouth waters in anticipation.

But no matter how good my system sounds at the end of the day the room acoustics have a massive impact on sound quality. And that applies even when the speakers minimise those problems as the Orelo's are designed to do.


Paul

[acg]

I have also heard Peter's system and it just does not happen at his which is in a very big room with lots of space between the outer edges of the speakers and the side walls. No such luck here there are lots of side wall reflections because so close.

The larger the room the lower the Schroeder frequency and the fewer room nodes...that is simple physics.  I would love a big room for audio, but that is not going to happen anytime soon.

[arvind]

Hi Mani,

Sorry to hear about the problems faced by you with the Orelo in your set up. My room size (8.5x5.6x2.7) is pretty similar to yours, except for the height.

The Orelo is placed 70cm from the back wall & 50cm from the side wall. About 4.0m between speakers (centre to centre). Practically negligible toe in. Listening position is 5m from the speakers.The low end is one of the best I have heard & mind you I have done no dsp settings.

As a matter of fact with my previous speakers, I was facing an issue of standing waves at 60/63Hz & to eliminate that I had bass traps installed. The first thing I threw out of my room, were these traps & now no standing waves.

Currently my only disappointment with the Orelo in my set up, are the upper mids, they are a bit harsh & smeared. Bert is working to find a way to solve this. At this point I would say that the tube amps work better in this area. More musical & involving.

However if your issue is related to room modes it's unlikely that it would differ from one speaker to another. I would think so.

Best regards,

Arvind

[manisandher]

I just wanted to give my impressions of Mani's sound with Orelo's as I have heard his system many times.

Thanks Paul, that puts a lot of things into perspective. Yes, I could have persevered with the Orelos, but I suspect it would have taken a suspended ceiling to really make progress, and I'm not about to ruin the great job the Victorian builders did 130 years ago (when British engineering led the way... how times have changed!).

My system will never sound like yours - yours assaults the senses (in the best possible way - the visceral impact really has to be heard to be believed), whereas mine massages them (but only when using a SET).

Mani.

[manisandher]

The low end is one of the best I have heard & mind you I have done no dsp settings.

Hi Arvind, that's really good to hear. Anyone looking for end-game speakers with decent bass should have the Orelos right up there on their list.

Currently my only disappointment with the Orelo in my set up, are the upper mids, they are a bit harsh & smeared.

I don't think I ever came across this issue with mine - perhaps with certain XX settings. Have you tried playing around with SFS and Q settings to see if you can tame this? Otherwise, I'm sure Bert will come up with something.

Mani.

[PeterSt]

Hi Mani, thank you for your help.

Although anything might be helpful to Arvind's situation, the problem is partially psychological because we (Arvind, Bert and me) know that something went wrong in there during production of this particular set.

Best regards,
Peter

[PeterSt]

If I play a test tone of 50hz and then walk all the way to the listening position you virtually cannot hear it at all. So where does the 50hz go?

Hi Paul,

Of course with the remainder of your long post as context :

I think you should run such a room mode calculator for the two parts of your room and most probably you will see that no voodoo is going on (I know you did not state that, but as long as we don't understand it often ends up as that ).
So what I dare predict is that all the longitudinal way the 50Hz is cancelled out because of the height of your room and then combined with the width. This makes shifting the back or forward the listening position not a solution. Btw, the same was going on with Mani's although I recall something else as 50Hz for that, but never mind.

Now run the same calculator through your conservatory of which you already know that at least the width is very different. With a bit of luck in there the 50Hz rules the other way around and instead of a notch because of cancelation you have a peak because of addition. It would be very coincidental, but it can happen.

Btw initially - when I read your post - I had the idea that the 50Hz would bounce back from the wall behind you and work out in the conservatory. But I don't think I can justify that together with the cancellation in that part of the room where also the bouncing back should occur.  A bit of a far sought option would be that the wave travels along e.g. the ceiling (or any of the other 3 surfaces) which you did not observe (measure) and works out to normal listening height in the conservatory. If you use a tool which can visualise where the wave of interest is audible, you will see it in there. So *if* you can see that the 50Hz is somewhere still for sure, it would be my bet that it works out in the conservatory. Thus not of what the back of the speaker is doing, but what bouncing back from the wall behind you implies.

This stuff is not to be underestimated. For example, Bert has had his large Orelo's in the middle of his room (similar to you, Paul). Well, if you did not first go to the normal listening position (with a nice flat / straight wall behind it and even corners) and listened from behind the speakers (face to the listening position), you would buy the speaker, so normally is that sounding all over. And mind you, that is in the face of the back of the (open) woofers !!
It is only that when later listening from the normal listening position you'll easily hear more highs. But actually you had no idea that they lacked and more importantly, all was in proper balance (distance from behind the speaker to the opposite wall is about 6 meters).

Regards,
Peter

[Scroobius]

Hey Mani

the visceral impact really has to be heard to be believed), whereas mine massages

So is what we are aiming for is a system that provides a "Visceral Massage" well maybe but I suspect that the two are mutually exclusive  .

It would be easy to get the impression that I only ever listen to music at silly high levels - that is not the case - my listening is mostly at very modest levels (really......... !!)

P

[arvind]

Hi Mani,

Thanks for the suggestion, although I have exhausted all permutation combinations of sfs, Q & filter to no avail.

Finally the only thing that partially works is reducing the slope & dip on the Orelo, though it's not the ideal method.

Hopefully Bert will fix the problem soon which could lead to solving this issue too.

Best regards,

Arvind

[manisandher]

... [my system] massages [the senses] (but only when using a SET).

I think for the first time ever, I've got a system that actually helps me to relax. Personally, I now think single-ended amplification is necessary to achieve this. I'm sure most people here would disagree, and I could certainly be wrong. But let me just quote something that Nelson Pass has written about this:

Given the assumption that every process that we perform on the signal will be heard, the finest amplifiers must employ those processes which are most natural.

There is one element in the chain which we cannot alter or improve upon, and that is the air. Air defines sound, and serves as a natural benchmark.

Virtually all the amplifiers on the market are based on a push-pull symmetry model. The push-pull symmetry topology has no particular basis in nature.

Is it valid to use air's characteristic as a model for designing an amplifier? If you accept that all processing leaves its signature on the music, the answer is yes.

One of the most interesting characteristics of air is its single-ended nature. Sound traveling through air is the result of the gas equation:

PV1.4 = 1.26 X 104

where P is pressure and V is volume. The small nonlinearity which is the result of air's characteristic is not generally judged to be significant at normal sound levels, and is comparable to the distortion numbers of fine amplifiers. This distortion generally only becomes a concern in the throats of horns, where the intense pressure levels are many times those at the mouth, and where the harmonic component can reach several per cent.

We can push on air and raise the pressure an arbitrary amount, but we cannot pull on it. We can only let it relax and fill a space as it will, and the pressure will never go below "0". As we push on air, the increase in pressure is greater than the corresponding decrease when we allow air to expand. This means that for a given motion of a diaphragm acting on air, the positive pressure perturbations will be slightly greater than the negative. From this we see that air is phase sensitive.

As a result of its single-ended nature, the harmonic content of air is primarily 2nd order, and most of the distortion of a single tone is second harmonic. Air's distortion characteristic is monotonic, which is to say its distortion products decrease smoothly as the acoustic level decreases. This is an important element which has often been overlooked in audio design and is reflected in the poor quality of early solid state amplifiers and D/A and A/D converters. They are not monotonic: the distortion increases as the level decreases.

Mani.

[Scroobius]

I've got a system that actually helps me to relax. Personally, I now think single-ended amplification is necessary to achieve this.

I have been there and spent a serious amount of time and money to get what I thought a SET system could deliver but ultimately it just didn't. Having said that I remain completely open minded and look forward to hearing your system.

Paul

[manisandher]

I have been there and spent a serious amount of time and money to get what I thought a SET system could deliver but ultimately it just didn't.

Hey Paul, you never used a full horn system with SETs though, did you? High efficiency (>105dB/W@1m) is a must to get the best out of a SET, I think.

Having said that I remain completely open minded and look forward to hearing your system.

Well, be prepared to be underwhelmed. It doesn't sound particularly impressive to my ears, mainly because it doesn't bring any part of the sound to attention. I haven't thought, "amazing bass", or "amazing dynamics", or anything like that. But what I have noticed is that I sit through whole albums just listening (no playing on the laptop) and am surprised when the album finishes.

And I can't even suggest that it sounds 'real'...

Mani.

[briefremarks]

Mani,

I've had the same experience as you in the past about being more "relaxed" listening to the radio, or even my in-wall speakers, than to "hi-fi" systems.  Once one reaches a certain level of quality, however--and this has been the case for me only recently with Stealth, RAM-OS, XXHE and Phasure--I find myself listening as if at a concert, not necessarily critically, and music is music again, without worry about the "system."  There is an unexpected quality to this experience, just as when one hears an unexpected sound in real life, a sudden "what was that?" feeling.  So the music does draw attention to itself, but not to marvel at the "system" but to be immersed in the piece itself and the performance.

Ramesh