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In Reply to: RE: General speaker design characteristics for a 2A3 amp posted by saki70 on April 11, 2017 at 11:59:39
Most of the comments so far have been fairly detailed. So I will attempt to take a broader (and more technical) tack.
First, a SE 2A3 amp will give you no more than 4 watts (and that with a tailwind). That would normally call for 96dB/watt efficiency, which is fairly rare - your choice of speakers is quite limited. Without going into excruciating detail, this is what I call satisfactory to most audiophiles, most of the time. Many will be satisfied with 1/4 the efficiency (90dB/watt efficiency), especially if you don't need full symphonic or big band loudness. Since efficiency and bass extension both require large cabinet volumes, you probably need big cabinets unless you are listening only to sopranos with acoustic guitars. :^)
Second, an SET amp usually has no feedback and thus a damping factor in the range of 2-4. Few speaker systems are designed for that; most assume a high damping factor in the range of 10 to infinity. Therefor most SETs will produce more or less uneven deep bass, and many speakers will also have uneven response in the crossover region. This is an interesting technical point, but the marketplace offers little or no relevant data - the best approach in my mind is to listen to them yourself, preferably at home with the amp you are interested in, or at least a similar one.
Everything I have said above is of course grossly simplified. I expect there will be many expansions/corrections/etc, and that's fine with me.
Your assessment is admirably objective, right down to (and including) the conclusion.
One should listen as much as possible and decide what one likes.
(or be prepared to do a fair amount of 'flipping' -- acquiring components, evaluating, and then de-acquiring the ones that don't meet one's own aesthetic standards).
The bottom line is that, ultimately, one's preferences are generally very personal and subjective; as they say (and I don't mean this perjoratively) "de gustibus non est disputandum". I know what I like; but it's hard for me to predict what "you" will like.
all the best,
This isn't meant to be argumentative, so bear me
out-- just take it as a glimpse into Theatre-Style Hi-Fi.
4 watts is a LOT of POWER! I have yet to hear a speaker--
regardless of cost- that needs over about 1/2 watt that
can even remotely approach delivering real-life dynamics,
musical energy that can follow the musical "grooves", etc.
If you can find one-- regardless of price or amp power,
then show me..... I've never heard it happen.
You start losing music when you need more power.
More power can deliver the needed power and bandwidth.
What it can't deliver is connection to music because the
speaker and the amp is now using up the voltage swings
of micro dynamics.
Of course, more power can easily restore this ratio-- correct?
Nope. It just doesn't happen in real life, Sorry there. The extra
power makes it worse yet, Now, even more small signal is lost.
Overwhelmed by too much current.
If one could buy a 115db/watt woofer that was built right, he
would find today's best--- 101db units-- to sound muffled and
lethargic by comparison.
We all have to live with what we can actually buy.
Your choice of speakers is quite limited. Limited in what sense?
All of the world's best speakers are about 99db/watt or better.
That's not limited to me. I would say they're the only ones to buy!
You probably need large cabinets... You MUST have them!
These large cabinets are not an option, they're a minimum
Damping factor confuses me because everyday I hear small S.E.
amps delivering the best, most outstanding deep bass that any
equipment of any kind out there is delivering. It goes deeper,
is much faster, it's cleaner, and its start-up and cutoff is
A good amp will not cause a woofer cone to visibly move-- at all.
Damping factor? That is the ideal, isn't it? So why, then, is the
calculated damping factor so low with S.E. amps? It's just my
opinion but I would be looking at power supply characteristics
and internal amp wiring, not to mention speaker cables and internal
driver and crossover wiring before I would get all wrapped up in
Damping Factor theory.
A good point here is that many modern drivers are designed to
run on solid-state amps that have high D.F.
Historically speaking, those drivers were designed not to make
music but to avoid warranty problems from burned-out voice coils
operating on high-current amplifiers. Looser machining created
more air cooling, and heavier voice-coil wire handled more
current. Result? You lose 90% or more of music's most dynamic
and compelling performances.
We have a lot of deliberately-designed crappy drivers today, but
we can also buy the best High-Eff., low current drivers that have
ever been made. Examples are: GPA, ALES, and a whole group of
reasonably priced items from Radian, and from Germany and Italy.
We also have some "pro" drivers that guitarists are using, made
in Tennessee, and in other places in the USA.
Some of these are really good, and are low-cost.
We do have a problem in accessing relevant data, but most
speaker driver's specs help us out a lot.
You don't need a lot of watts, but you do need large
cabinetry and outstanding, well-machined and tightly
constructed (efficient) drivers.
Since you can easily lose the whole thing with too small
speaker and crossover wiring or inferior wire metallurgy,
you have to carefully address that area also.
This is a good argument for bi-amping. Get some muscle for the bass, and cross over at a low enough frequency to use the SET amp where it performs best. You really can have the best of both worlds.
Have Fun and Enjoy the Music
"Still Working the Problem"
Attacks and decays matter far more to our hearing and affective systems than do continuous tones and their harmonics.
Electrostatic speakers are very efficient, but they are not at all sensitive.
I've not heard any speakers that get closer to the sound of real stereo of acoustic music than 'stats can, if set up right.
Large efficient boxes - esp. horns - can get close, but no cigar.
I've been a chorister since age nine, and went through the RSCM's training. And I listen to live acoustic music at least once a week.
You seem to be confused between sensitivity and efficiency. Efficiency matters, sensitivity is far less important.
BTAgain your being confused about audio as a system, is not knew to us here.
In any work requiring systems analysis (audio IS is a systems problem) there can, for some, be a proneness to going down 'interesting rat-holes'.
Trouble with the kind of thinking that gets you down there and keeps you there / makes it quite hard to get back up and out.
Interesting rat-holes are a waste of time.
Skeptical Measurer & Audio Scrounger
I also have heard good electrostats sound real
and lifelike..... in some ways.
I'm never interested in just ONE WAY of
thinking-- about anything. Show me something
that really works, or an idea that might, and
I'll be right on it.
What I might object to is constant wranglings
excusing what does not work as well musically.
As an interesting aside, consider the many
excellent headsets out there today.
One can choose from many different dynamic or
"stat" models, and can choose either, or in some
cases, a combo of both technologies in the same
In that case, it's simple: choose the one that you like...
In the listening room, both "stats" and dynamic models
can involve the room well-- but there are different
actions and activities going on musically in the room
with each topology.
There certainly isn't any rathole here, simply
choose which topology fits your room and tastes the best..
In both cases, rather large radiating surface areas are
the best way to fully engage the room at low distortion.
Dennis wrote "In both cases, rather large radiating surface areas are
the best way to fully engage the room at low distortion."
Dennis, may I safely assume that you consider horns to be large surface area radiators because the impedance matching provided by the horn makes the mouth of the horn the effective radiating surface instead of the diameter of the driver driving the horn?
Horns are all different with differing
lengths and flare-rates, and geometry, so
no fast and easy rule...
Generally, the efficiency gain is about 3X--
maybe more, maybe less. In general, distortion
levels drop as efficiency increases.
Room coverage is bettered by the wider coverage
angles in most cases.
Remember that this all started in movie theatres
where owners liked the idea of covering 1000 people
with 8 watts. As movies got better, the speakers
had to keep pace, so both efficiency and bandwidth
were increased. Distortion levels plummeted as better
drivers and loading schemes continued to advance.
Without movie theatre's insistence on providing a
sense of presence and a sense of realistic dynamics
and voice accuracy, we'd be stuck with panels and
Clock-Radio speakers that can't get it up...
Oh, Wait! Many are using those anyway!
David Hill and James O'Donnell, I can tell you that tones and harmonics matter, just as much as transient fidelity and decay. I also attended the Royal Academy of Music. Is that enough willy-waving?
Since no one speaker system gets it all right, why the worry? Besides which, if you've ever listened to decent compression older drivers like the Vitavox S2, or the recent B&C DCM50 in a sympathetic set-up, you might find you can have a lot of your cake and eat it too.
"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."
We'd have to be able to do that, because percussion instruments don't do continuous tone. And they all have their own characteristic timbre. Even cymbals of the same type & dimension, but of different make.
We really do pay far less attention to the continuous tones, for those instruments that do them.
Pianos for example don't do continuous tones, it's all attack and decay.
Of course pitch matters, 'If you can't pitch, you can't pitch'. It's how you start, no? Very big effect on what happens next, no?
Knowing this, we ought to require that audio reproduction systems should have matching rise and decay behaviour, and fast enough to boot, too few do. 'Stats do, and they engage with rooms less than other speakers.
The trouble with horns is the steep filters so many need between each driver. Some even need notch filters within their pass band, because they ring. So, their impulse and step response is poor compared to a FR 'stat.
I've heard quite a few 'good' horns including ones with Vitavox drivers and their speed is quite good, but their coherence can not match that of a QUAD FRED (the 63 and on).
My favourite horn was one of the bigger designs by 'Tommy Horning' with most of the range covered by a de-whizzerd Lowther driver. Plus deep bass and treble assistance. IIRC with minimal odd-order filters.
I've known Klipschorns and Lowther based horns since my twenties, I'm now 66. I used to work weekends in Canberra's oldest audio shop.
I find equal temperament eventually tiring, can you tell me why that might be?
I don't do willy waving, but I do like clear informed thinking.
Skeptical Measurer & Audio Scrounger
Hi Tim, FR STATS share similar problems with so called FR cone speakers in that IM distortion is the dominating factor of distortion and its audible very much audible, you pick what you like and THATS that..
but IMO 8 way 13-80kc covers all the octaves with less distortion(including the terrible IM) then any STAT will now... Meet Fulton the ,Large premiere's only speaker that can play a grand piano like no other :)
now some people may disagree with me and that fine because there is no horn system, lowther, STAT, that will play like the real thing in your home like the large fulton system can.
high sensitivity does not mean hi fidelity.
Edit: for jeff :) a large fulton speaker with the "80 driver" for the mid-range will play and sound very similar like a real piano is what i mean to say organically
I have always thought that 63s and later small models need to be filtered and given subs. Between 100 and 150Hz. When you do that diaphragm excursion is quite limited.
Tom Danley (aka TomServo) agreed with my proposal following.
Ist order HP and 3rd order LP @ 150hz. Because using 4 monopole subs* in a swarm arc at the same listening distance. When the diaphragm excursion ceases to be a problem, and the room-gain totals relatively smooth at the listening seat. Lots of amplifier power needed for the bass.
That's what I am slowly building, on a limited monthly of <$ Au 400 budget. Dipole subs are way out of my budget.
* two large push-pull sealed subs as stands, and two tall EBS (Rb) subs to the inside of the QUADs corner edge on and 2nd HP filtered down below pedal reeds.
I'll use a bit of Eq if needs be, and later go with DSP as funds allow.
Skeptical Measurer & Audio Scrounger
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