Do Compression Drivers = Distortion?

[Storm]

As I was searching google for Altec Valencia Speakers, I found an image that when I clicked on the link -- someone posted it to show an exampe of a compression driver.

They said compression drivers equal distortion and to only listen to ribbon speakers. Is this true? If so, to what extent?

Here is the link and excerpt:

http://srforums.prosoundweb.com/index.php/pv/116/0/0/#msg_156845

I would also take issue with you regarding your great system. Sorry. Tangerine phase plug Altec or not, if you use a compression driver then you are listening to large amounts of distortion. Try listening to a proper system with ribbon drivers.

I am sure that the majority of problems that HiFi buffs complain about at concerts, Is either a) the mix or b) the acoustics of the venue.

Best.

Iain.
London UK

___________________

Thank you for your help.

-Storm

:)

[Ian Mackenzie]

Distortion in both comes down to excersion limitations at the lower end of their useful range.

Provided your Altec driver is loaded with the right horn and crossover it should deliver low distortion for home use.

Don't expect it to compete with the most expensive Scanspeak Revelator dome tweeter, it won't. In that respect the Altec ain't Hifi.

Ribbons. Its the biggest bullshit story floating the www at the moment.

By design they have shocking distortion at the bottom end of their quoted range. The marketing is all hype. The massive 2 harmonic distortion sounds nice to some. But they work well as a super tweeter.

Ian

[edgewound]

A very interesting exercise is to put a ribbon tweeter on a sweep generator and then just listen as you sweep through the audio range.

When you can hear the harmonics over the fundamental....that's a problem....they are very poorly damped.

Ian's right. The midrange just can't compete with either a comp driver or dome.

[boputnam]

Distortion in both comes down to excersion limitations at the lower end of their useful range.

Provided your Altec driver is loaded with the right horn and crossover it should deliver low distortion for home use.

Don't expect it to compete with the most expensive Scanspeak Revelator dome tweeter, it won't. In that respect the Altec ain't Hifi.

Ribbons. Its the biggest bullshit story floating the www at the moment.

By design they have shocking distortion at the bottom end of their quoted range. The marketing is all hype. The massive 2 harmonic distortion sounds nice to some. But they work well as a super tweeter.

Ian


A very interesting exercise is to put a ribbon tweeter on a sweep generator and then just listen as you sweep through the audio range.

When you can hear the harmonics over the fundamental....that's a problem....they are very poorly damped.

Ian's right. The midrange just can't compete with either a comp driver or dome.Nothin' more needed - should just close this thread...

[Maron Horonzakz]

Ribbons or planer speakers,,,I can piss louder than those speakers...Poor dynamics.

[Steve Schell]

Its a good question Storm, but the answer depends on the situation. One might possibly find a ribbon tweeter that would measure lower THD than an Altec compression driver/horn at low levels, especially at high frequencies where the Altec diaphragm is breaking up while the ribbon is still moving as a piston. The ribbon will also maintain flat power response to a much higher frequency than the compression driver. If things get loud though, the Altec will remain fairly clean to levels in the midrange that could easily destroy the ribbon.

I agree with Ian and edgewound about the problems ribbons have down low- not their forte at all. Crossed over above 5kHz. or so though, they can be marvelous. Their ultra low mass gives them a huge advantage in the top octaves. When I was working on some home brew field coil ring radiator tweeters years ago, I had a heck of a time trying to get the moving mass under 200 milligrams. Ribbons are often under 15 mg., so they excel up high. The dynamics of a horn loaded ribbon can easily keep pace with the rest of a horn system... they are dynamic speaker after all. They just have a straight rather than coiled conductor, and the ribbon serves as piston as well as conductor, an advantage.

When someone makes a blanket statement like that fellow did though, the distortion level is usually very high.

[rich carnese]

It seems to me when we talk about measureable results for loudspeakers we forget something. They dont necessarily translate into what it actually sounds like. It has even been said in many other forums that even the JBL engineers felt that the older alnico units,even though higher in measureable distortion tests...sounded better. In my opinion sometimes a driver does something better that is not measureable. I lived for quite some time with some highly regarded modified Panasonic Leaf tweeters. they had very extended response. They were very fragile and compared to a compression driver had much more power compression, less headroom and as a result a more limited dynamic range, and less realism.
Compression drivers(well loaded and good crossover design)never sound strained to me, the way a dome or ribbon can. I realise I havent heard everything out there....but. Maybe I'm just used to them...lol