Single-ended triode amps

[manisandher]

Hey Anthony, thanks for the insights - very interesting.

But I don't think I'll be messing around with the Orelo speakers. The DSP and servo-assisted bass is an integral part of the design and can work incredibly well - anyone interested should just take a visit to Paul's place to hear this, with his slightly smaller Orelino speakers (if Paul's willing, of course). The 211 SET amps totally transformed the sound of my Orelos overall, but had little affect on the bass, which suggests to me that the 'quality' of the bass is being determined by the DSP and the servo-assistance. No matter what I try, I can't seem to get the low end right in my room with the Orelos.

Mani.

[PeterSt]

No matter what I try, I can't seem to get the low end right in my room with the Orelos.

Of course you will.
All it needs is a bit of "complaint" so we can work on it. Only the other day I had an idea but it appeared practically difficult (so I didn't announce myself while you don't even complain ).

Peter

[PeterSt]

I can confirm that it is possible for SET amps to have zero noise on high efficiency horns.  I am talking put your head in the horns and hear not  whisper.

Hi there Anthony,

If you know the efficiency of your horns (I'm sure you are referring to those ... what is it ?

The beauty of SET's is that their level of distortion decreases as their output decreases,

Isn't it so that you bring this a bit the other way around : these amps (means of amplification) are full with distortion but with some lower load they are fine ("better" would be more realistic).

THD ?
I'd be careful, because the THD could be higher than even a speaker (I am not sure any more, but I recall something like 0.02% THD from the (Orelo) mid/1KHz at 120dBSPL - maybe it was 0.2% but it doesn't matter really when we start out with tubes. Or ?)

Anyway, it is difficult for me to be part of the discussion, especially when noise is so high that it can only be destructive while people claim it sounds better.
Well, I don't need to say what's next, right ?

I suspect this post will ruffle a few feathers,

True.

haha

[acg]

Hi there Anthony,

If you know the efficiency of your horns (I'm sure you are referring to those ... what is it ?

113dB one watt one metre [EDIT: and with AC filaments which are generally considered noisier than DC]

The beauty of SET's is that their level of distortion decreases as their output decreases,

Isn't it so that you bring this a bit the other way around : these amps (means of amplification) are full with distortion but with some lower load they are fine ("better" would be more realistic).

THD ?
I'd be careful, because the THD could be higher than even a speaker (I am not sure any more, but I recall something like 0.02% THD from the (Orelo) mid/1KHz at 120dBSPL - maybe it was 0.2% but it doesn't matter really when we start out with tubes. Or ?)

Yes, some SET's have quite large 'distortion', pretty much all second order, but it seems to fit with our physiology somehow and sound fine/not there.  I have seen SET measurements at speaker loads (ie. not running flat out) where the distortion is less than good SS at the same levels, but the key is high sensitivity and matching the amplifier to drivers that are not impacted by the shortcomings of the topology.  It sounds like the horn on the Orelos is a good match.

If low distortion was the sole metric by which to measure amplifier performance we have been at the pinnacle of audio amplification for a quarter century...haha...not true...but it certainly low distortion is very important.

Cheers,

Anthony

[acg]

No matter what I try, I can't seem to get the low end right in my room with the Orelos.

Mani.

As you are no doubt aware Mani, good low end is mostly about positioning.  Positioning of the speakers and positioning of the listening chair...both should be positioned with consideration of measured SPL for frequencies below the rooms Schroeder Frequency, usually somewhere near 250Hz.  Walking around with an RTA finding the room nulls and peaks for various frequencies is probably the best place to start...shift the speaker...get out the RTA...and iterate.  Once the speakers and chair are placed for best bass response then fine-tune the positioning to get the sound and imaging you want in the higher frequencies.

It takes a lot of effort to get right.  Have you read Jim Smiths book?  That is a good place to start.

[manisandher]

As you are no doubt aware Mani, good low end is mostly about positioning...

... It takes a lot of effort to get right.

Yeah, sure Anthony. In the old days, I used to spend hours/days with 'golden ratios', etc. My Orelos, with their currently sand-filled wings, weigh in at about 150kg each. Also, they're quite big in comparison to my [approx.] 6x5x4m room. So by necessity, they have remained sitting relatively close to the corners of the room since I received them.

In any event, I'm not sure if OB speakers can be treated in the same way as IBs, ported, etc.

Mani.

[acg]

In any event, I'm not sure if OB speakers can be treated in the same way as IBs, ported, etc.

Mani.

Where the wavelength is longer than any room dimension, the room is the instrument, not so much the speaker.  IB has to obey the same rules of physics as any other topology.  My horn stacks when they are finished will be about 500kg each...I still plan to move them around to find where they best 'play the room'.

[PeterSt]

But Anthony, you are out of space anyway !

[manisandher]

There will be a permanent SET setup in my office and in my main room by the end of the year. I cannot listen to anything else now.

Done!

Mani.

[acg]

wow!

[manisandher]

wow!

Yeah, and to my ears, they sound as good as they look. They certainly seem to match the room (sonically and aesthetically) better than any other speakers I've ever had in it.

And now to that NOS1 upgrade we've all been hearing about... 

Mani.

[briefremarks]

Mani,

I saw these Tune Audio "reproducing machines" as they call them when I was researching speakers.  As I understand there is a downward firing bass horn, and the mid and hi horns.

These seem to be in the same spot as the Orelo's were.  How do they compare?  The reviews on the website are in Greek and French, so not accessible to me.

I am, of course, awaiting the arrival of the Orelos.

Ramesh

[manisandher]

How do they compare?

Hi Ramesh, there's no question in my mind that the Animas are better suited to my reasonably small listening room (~6x5x4m) than the Orelos. The Animas respond well to being placed pretty close to the corners, and I think this is where they differ mainly - I am now convinced that the Orelos need a couple of meters of breathing space behind them to perform well in the LF. Paul has a lot of breathing space behind his Orelinos, and they sound superb.

Certainly, I have absolutely no issues with bass in my room with the Animas. I'm getting a beautifully balanced sound, which I never achieved with the Orelos without some serious DSP in the LF, which brought along a whole new host of problems, as I discovered over time.

If I were typing this a few hours ago, I would have said that the Animas are way more laid back and less dynamic than the Orelos. But I've just connected my BD-Design mono amps to the Animas to give the speakers a bit of a continuous thrashing (get them loosened up a bit) and I'm hearing quite a few similarities now. I still doubt that any amp on the planet would get as much drive out of the Animas as you can get with the Orelos with their built-in amps.

If you can get a sound even half-way approaching that of Paul's set up, you'll be in for a real treat. If I could have gotten the Orelos to work in my room, I absolutely would have kept them. But I have to say, I am really enjoying the SET sound with the Animas. I just know this SET/speaker set up is the end game for me.

HTH.

Mani.

[PeterSt]

Hi Mani,

Very nice looking ! really so.

I am now convinced that the Orelos need a couple of meters of breathing space behind them to perform well in the LF.

Allow me to tell you "better not be", because how else is it working out elsewhere, including my own room (say 80cm from the wall behind them). If only we would have worked this out then we would have know (and solved it), but we did not ...
The above is only the necessary lead-in to an observation :

As you know, the Orelo's explicitly fire less backward than forward because of the wave guide set up. This is also the reason they are allowed to be very close to the wall behind them. They just are and they are everywhere where I listened to them myself. Now :

The Animas have a downfiring woofer. So, not even forward firing (say without port) but explicitly downfiring, which means thay radiate 360 degrees and thus also right into the corners. And now something else happens (outside of phase stuff which I wouldn't like for theories, but that's me ...

So as we both know you suffer from these room modes. I forgot by now how or what, but together with your "odd" high ceiling, that did not work out as you would have wanted. But what is a room mode ?
Well, let's say it is a tight/small area where waves meet and cancel (your situation) or add. Why is that area tight ? well, WHEN the beaming as such is that in the first place. So as we know the bass from the Orelo design is the most directive but which means that it comes to you without too many (early) reflections, especially not from the back. And this now is crucial ...

Let's assume that your speaker is 1 meter from the corner. Or that the middle of the bass driver / opening is. This means that before the wave hits the corner (or wall) it has travelled 1 meter. Next it travels one meter back to the speaker opening where it meets with the next cycle without phase difference. Well, this is idle hope of course (is that Dutch ?), but let's say it works out. If it does ... same problem as with the Orelo ! haha. Well, some time smear, but that is all.
The idle hope though predicts that this is not going to happen at all, and most certainly not for all frequencies at the same time. And most of all not for the wavelengths longer than 2 meters, which are about all of them coming from there (I'd say, without doing any math). So ...

What you nicely created is some heavy smear for that tight area from before. That tight area is not that at all now and it allows the waves which met not to meet at all (read : they still do, but 15cm away they do not and the next effect is not a full cancellation).
That meanwhile it is quite messy is something else (you should be able to hear that by means of a lower bass (say more dark) but not as tight. Btw this could be harder to experience because the bass doesn't go as low as the Orelo to begin with, so even for me it is hard to predict in comparison.

But see ? now your problem of the cancellation is solved.
And when I am right on this, you could have solved the issue by means of moving one of the speakers a bit forward or backward (let the top horn stay in position). Well, sort of, for proof. It is not a real solution of course.

What's for sure is that they look seriously nice ! (thanks to that great finish I'd say ?)

Best regards,
Peter

[manisandher]

Very nice looking ! really so.

Thanks Peter.

If only we would have worked this out then we would have know (and solved it), but we did not ...

[snip]

And when I am right on this, you could have solved the issue by means of moving one of the speakers a bit forward or backward (let the top horn stay in position).

Over the two and half years I had the Orelos here, I tried a lot of different things, including different positions. I actually had them 1m from the rear wall in the beginning, and only moved them closer over time. Going from 1m to nearer the rear wall really didn't seem to change much here. Filling the wings with 240kg of sand didn't help the sound (nor my back!). The only thing that 'worked' was using severe DSP, but that turned out to be too much of a 'sledge hammer' approach and introduced other issues that I discovered later.

In any event, the ultimate test is using your own ears. And my ears are clearly telling me that whatever the issue was with the Orelos in my room, I don't have it with the Animas. To my ears, the bass sounds as clean as it did with the Orelos... just way more of it! What's not to like?

Edit: I want to make it absolutely clear that I'm talking about the performance of the Orelos in my specific room, with a 4m ceiling.

Mani.