Flip Side of the Coin

[leonski]

Back when hifi was a 'new' hobby, becoming more common with information available and even publications by the 50s, one thing was certain.
Your system would have lots of  Vacuum Tubes.   Nice, warm, glowing TUBES...
Stereophile magazine, started in 1962.    
Don't forget that at this time?   The Transtor had begun being used.   The first car radios (chrysler) and even the first SONY radio became available.    The race was on.

By the late 60s, transistors were coming one.   

But a very important change was yet to come.    Big Box speakers could make good use of a couple watts.  You could LIVE in these huge speakers.    
Bozak was one maker.   the Concert Grand was OVER 100kilos and made from the early 50s until into the 70s.   And would sound wonderful with 
what today wouldn't even make a modern speaker Squeek....

What happened was the modern LOW SENSITIVITY speaker.   The 'small box', usually acoustic suspension.   First among these and still collectible 
would be the AR2 or AR3a models.   The AR3a, was for me, aspirational...

Watts have dropped in cost for the last 4 decades.   But I'm not sure they are 'better'.

I'm currentlly exploring DECWARE amplifiers, handmade in Peoria Illinois and having a LIFETIME guarantee to the orignal purchaser.   Not as $$$ as the
major high-end stuff, still, maybe 100$ per watt for a 20x2 amp for higher sensitivity speakers......This is a NO FEEDBACK design with the one I'm looking
at putting out 20x2.    A slightly higher power and more $$ model is 25x2.   

Kllipsh and others STILL make high sensitivity speakers.  The Forte IV is over 95db sensitivity as measured by stereophile.  

If you don't like tubes?    Several lower powered SS choices exist, but speaker matching is CRITICAL.    Something like the First Watt in which NOTHING in the
line is over 50 watts at 4ohms......Some of these amps have fairly high output impedance so a speaker needing high DF will NOT sound its best.  

I'm seriously considering a full-redo and going low-power and high sensitivity speakers.   I'll leave my preamp alone.     
 

[mgbpuff]

I have nice low power set up; Either First Watt F1 or 300B SET driving a 96DB single transducer 1/4 length transmission line speakers. (I prefer the 300B SET). The preamp is a passive W4S design. I've also got a high power system with 550 watts/ch amps(Musical Fidelity) and a Cary tube pre driving Revel Ultra Salon II speakers and another Magnaplanar 3.6R speaker system driven by Emo Gen1 XRA-1s and an XSP-1. I listen to each one as the mood strikes me. My first hifi was a Marants 8B driving AR2ax speakers with a Dynaco PAS-3x preamp (still have them although the pre is inoperable, the speakers have the potentiometer problem, but the amp still workks with no changes).

[KeithL]

I'm sorry guys... but I have to laugh here...

In the really early days speakers were what we would call "infinite baffle".

Either there was no box at all or the box was so big it didn't contribute significantly to the spring force acting on the woofer's cone.

(Many of those early speakers had cabinets with sides so thin that sound passed right through or that vibrated so much they produced as much sound as the cone.)

And in those days, with amplifiers delivering only a few watts, most speakers were also quite efficient.

Then along came horns - which had very special cabinets - and which could be even more efficient.

100 watts/channel was considered to be adequate for a pair of big horns in a full-sized theater.)

Then you have bass reflex - where the cabinet acts as a resonant damper on the movement of the cone.

(This provided more precise control of the speaker cone - and so lower distortion - than infinite baffle.)

(The catch being that, like horns, the cabinet characteristics must be carefully matched to the driver you use.)

At this point, along came "acoustic suspension" or "air suspension" speakers...

In an acoustic suspension speaker the cabinet is sealed and the air trapped in the cabinet acts as a spring towards the speaker cone.

So now both the speaker cone's mechanical suspension and the springiness of the air in the cabinet contribute to pushing the speaker cone back towards its resting position.

(The air in the cabinet becomes part of the speaker's suspension - and so the name.)

My point is that, in the beginning, when acoustic suspension speakers were new, and AR was one of the first companies to make speakers that way...

And, in those days, they were universally viewed as "being able to deliver very low bass from a small cabinet - but at the expense of very LOW efficiency".

In other words, when they were  current models, compared to previous models, the AR3a and its contemporaries were considered to be very low efficiency speakers.

And they were considered to be one of the factors that drove the adoption of "higher powered push pull tube and solid state amplifiers".

[mgbpuff]

I think that the Edison disc players had a horn close coupled to a quartz crystal with no amp at all. How's that for old!

[KeithL]

I think you're thinking of the original crystal radios... which actually used a slightly different sort of crystal.

The original crystal radios often used a Galena crystal (a form of lead ore)...

(Actually a sort of semiconductor diode that was formed at the spot where a small metal "whisker" contacted the oxidized surface of the crystal.)

Later models used other types...

Quartz crystals are better known for their piezo-electric properties...

This enables them to be used as the active elements in piezo-electric microphones and speakers...

And in certain types of very accurate tuned filters and oscillators.

(Like the timing crystal in a "quartz clock".)

The original Edison phonograph had a mechanical needle coupled to a mechanical diaphragm.

The disc players were quite similar - although they substituted a disc for a cylinder.

Older phonographs used a steel needle (the proverbial "cactus needle"...

They wore out rather quickly...

But they were very cheap...

(You bought them by the box - like matches - and replaced them when they got dull.)

On the recording side...

You speak into the horn.

This causes the little diaphragm at the throat of the horn to move.

This causes the needle to move in and out.

Which cuts a groove of varying depth in the cylinder or disc (like moving the cutter on a lathe in and out).

On the playback side...

The needle rides in the groove.

The groove pushes the needle up and down.

The needle pushes the diaphragm in and out.

And the diaphragm pushes the air in and out just like the driver in a horn speaker.

In both cases the horn acts as an impedance transformer between the relatively massive needle and diaphragm and the relatively much lighter moving air....

May 19, 2021 9:09:47 GMT -5 mgbpuff said:

I think that the Edison disc players had a horn close coupled to a quartz crystal with no amp at all. How's that for old!

[mgbpuff]

May 19, 2021 10:04:37 GMT -5 KeithL said:

I think you're thinking of the original crystal radios... which actually used a slightly different sort of crystal.

The original crystal radios often used a Galena crystal (a form of lead ore)...

(Actually a sort of semiconductor diode that was formed at the spot where a small metal "whisker" contacted the oxidized surface of the crystal.)

Later models used other types...

Quartz crystals are better known for their piezo-electric properties...

This enables them to be used as the active elements in piezo-electric microphones and speakers...

And in certain types of very accurate tuned filters and oscillators.

(Like the timing crystal in a "quartz clock".)

The original Edison phonograph had a mechanical needle coupled to a mechanical diaphragm.

The disc players were quite similar - although they substituted a disc for a cylinder.

Older phonographs used a steel needle (the proverbial "cactus needle"...

They wore out rather quickly...

But they were very cheap...

(You bought them by the box - like matches - and replaced them when they got dull.)

On the recording side...

You speak into the horn.

This causes the little diaphragm at the throat of the horn to move.

This causes the needle to move in and out.

Which cuts a groove of varying depth in the cylinder or disc (like moving the cutter on a lathe in and out).

On the playback side...

The needle rides in the groove.

The groove pushes the needle up and down.

The needle pushes the diaphragm in and out.

And the diaphragm pushes the air in and out just like the driver in a horn speaker.

In both cases the horn acts as an impedance transformer between the relatively massive needle and diaphragm and the relatively much lighter moving air....

View AttachmentView Attachment

May 19, 2021 9:09:47 GMT -5 mgbpuff said:

I think that the Edison disc players had a horn close coupled to a quartz crystal with no amp at all. How's that for old!

Ah, you're right! That's what I get for speaking off the top of my head!

[leonski]

May 19, 2021 8:33:09 GMT -5 KeithL said:

I'm sorry guys... but I have to laugh here...

In the really early days speakers were what we would call "infinite baffle".

Either there was no box at all or the box was so big it didn't contribute significantly to the spring force acting on the woofer's cone.

(Many of those early speakers had cabinets with sides so thin that sound passed right through or that vibrated so much they produced as much sound as the cone.)

And in those days, with amplifiers delivering only a few watts, most speakers were also quite efficient.

Then along came horns - which had very special cabinets - and which could be even more efficient.

100 watts/channel was considered to be adequate for a pair of big horns in a full-sized theater.)

Then you have bass reflex - where the cabinet acts as a resonant damper on the movement of the cone.

(This provided more precise control of the speaker cone - and so lower distortion - than infinite baffle.)

(The catch being that, like horns, the cabinet characteristics must be carefully matched to the driver you use.)

At this point, along came "acoustic suspension" or "air suspension" speakers...

In an acoustic suspension speaker the cabinet is sealed and the air trapped in the cabinet acts as a spring towards the speaker cone.

So now both the speaker cone's mechanical suspension and the springiness of the air in the cabinet contribute to pushing the speaker cone back towards its resting position.

(The air in the cabinet becomes part of the speaker's suspension - and so the name.)

My point is that, in the beginning, when acoustic suspension speakers were new, and AR was one of the first companies to make speakers that way...

And, in those days, they were universally viewed as "being able to deliver very low bass from a small cabinet - but at the expense of very LOW efficiency".

In other words, when they were  current models, compared to previous models, the AR3a and its contemporaries were considered to be very low efficiency speakers.

And they were considered to be one of the factors that drove the adoption of "higher powered push pull tube and solid state amplifiers".

Yes....I skipped everything prior to the 50s.....when Bozak, Altec, JBL and even Klipsch made some really HUGE box speakers.    And yes, horns predominated.   
You support my 'ineficient' idea with the AR speakers.    I loved 'em, but couldn't afford THEM or the proper amplifier at that time...
Vented speakers of the Modern era were essentiall made possible thru the use of the TS measureables and associated calculations.
audiojudgement.com/thiele-small-parameters-explained/
Even design of IB speakers is effected by this data.

I didn't make any effort to be  'complete' but the general drift (starting with big box) to modern low sensitivity speakers goes HAND IN HAND with the invention and later semi-perfection
of the 'Transistor'.....
Heck, I've STILL got my Bugs Bunny Wrist Radio!

And if you really want some Old and New...    Check out field coil drivers.    I've heard some and it was special.   And fairly expensive.    but NO permanent magnets!

[housetech]

I loved my AR3a speakers. Yes, they needed some serious power (100-150w class A) to sound great, which meant running separates.

My college buddy & I made a pair of speakers, 6 feet tall- Altec Lansing horn & two 15" JBL inside 3/4 plywood with 1x2 bracing that rocked the house. Needed a dolly to move them, so we put them on casters. lol  Cabinet design, what's that?!   I just copied stage speakers size. If I could have found some Leslie horns, omg, we would have used those.
We got invited to a lot of parties if we would "loan them out" for the night. They burned up a few receiver amps. So we got a couple Marshall guitar amps, that did the trick.

Last time we spoke, he still had them.

[audiobill]

PBN m2!5 speakers, two 15s and a horn.

Only $30k the pair....

positive-feedback.com/reviews/hardware-reviews/pbn-audio-m25-loudspeakers/

[leonski]

I wonder if those PBN speakers NEED a high damping factor or they'd be happier with Tubes? Not that I can actually AFFORD 'em......