hey deano (snipers and the jub envious, STAY AWAY)

[mikebse2a3]

If the Voltage increases for example as the Drivers Impedance increases the current that actually flows through the voice coil could decrease Mike so the Acoustical increase from the higher driver's terminals voltages might not happen if the current is reduced due again to the driver's impedance rise. This does make the acoustical response of the driver harder to predict in the real world when driven by amplifiers that have higher output impedances such as SET types but even some Solid State amps such as some designs by Nelson Pass of Pass Labs exhibit this also.

Yea, you're thinking about power - not the voltage like you should be [][] Just because the amp isn't working as hard doesn't mean the acoustical output doesn't goes up (in fact, efficiency of the amp is at a maximum when the output impedance matches the conjugate of the load impedance).

Man I never have enough time for this hobby Mike! As far as getting a pair of Jubilees seems like you can justify them for a research project![]

Purchase Jubilees for a research project?!? Wouldn't the point of research be to build something better? [][]

Mike your making me think to hard[] it's been a long time since I really thought about this and I do agree that if the Terminal Voltage on the driver increase that the Acoustical Output in Theory should increase. But in the case of real world loudspeakers a rising impedances of a driver I believe might not always correlate to an actual increase in Acoustical Output in a case like this. In other words I don't think we can assume that just because we are using a SET amplifier for example with a high output impedance and we see a rising driver impedance that this will "always" corelate with an increased acoustical output from the driver(see quote below about assumptions of a loudspeaker modeling).

Here is an article I read a while back that you might want to check out if you haven't already. It points out in some situations how a high output impedance can be of a benefit.

http://www.firstwatt.com/downloads/cs-amps-speakers.pdf

A quote from the article:

Power Transconductance Amplifiers (Like Some Tube Amplifiers)

This is a fancy name for a power current source. An input voltage causes the amplifier to

deliver a proportional output current. Of course this same sort of thing would occur with an

ordinary amplifier driving a pure resistance but a loudspeaker circuit is not purely resistive. It

possesses numerous reactive elements, some due to inductance and capacitance in the

electrical circuit, some from the reaction to motion of the voice coil in a complex mechanical

system. Fed by a voltage amplifier, the current through the drivers voice coil is not directly or

instantly proportional to the input to the amplifier. Ordinarily, loudspeakers are designed

around this assumption but the piston model of loudspeaker design assumes that the

acoustic output mirrors the acceleration of the voice coil/cone assembly over a specific range

and this is reflected by the current through the voice coil.

For anyone interested this is a more standared view about Amplifier Output Impedance goals for loudspeakers designed with this in mind. This has a model that helps to show what Mike has been saying. Tube Amplifiers definitly can alter the sound of a speaker tonally whether we like it for the better or worse.

http://www.transcendentsound.com/amplifier_output_impedance.htm

Now I've got to get some sleep DR WHO

mike tn[|-)]

[JJkizak]

Not that I have a need to know but did anyone price out the cost of a Jubillee from Klipsch? So that you would not have to construct same?

JJK

[anarchist]

Most of the folks here bought their setups from Klipsch. Few here have built the LF bins themselves.

[anarchist]

Mike, yes, I'm still using the Super-T.

Dean,

Ya' know, I could lend you a proper tube amplifier. []

[DrWho]

Mike your making me think to hard[] it's been a long time since I really thought about this and I do agree that if the Terminal Voltage on the driver increase that the Acoustical Output in Theory should increase. But in the case of real world loudspeakers a rising impedances of a driver I believe might not always correlate to an actual increase in Acoustical Output in a case like this.

The only way that can happen is if the voltage transfer characteristics of your amplifier don't change with the load impedance. Since that's the case for all SET amps without negative feedback, then you've got something along those lines going on. Whether or not it sounds good or works well with the system is a completely different issue.

Here is an article I read a while back that you might want to check out if you haven't already. It points out in some situations how a high output impedance can be of a benefit.

http://www.firstwatt.com/downloads/cs-amps-speakers.pdf

No offense Mike, but that article is full of "audiophile magic" and

[bs]...not sure if I'm qualified to say that or not, but I've got a

textbook here that disagrees with about every side point he makes. For

what it's worth, it's actually easier to build current sources

(especially with solid state), which makes it seem odd when he keeps

referring to the "SS of the 60's". Nevertheless, though he doesn't

state it explicitly, he is taking advantage of the non-linear

characteristics of his amp to boost the low-end on his speakers that

need a ton of boosting in the low end (the same rising output with a

rising impedance problem). I guess you could just say it's convenient

that he's got a rising impedance as the frequency goes down. But frequency response doesn't tell the whole story and I can attest to the fact that the speakers to which he refers sound like complete garbage (which is gonna be due to all sorts of other things you can measure). However,

in the case of the Jubilee, or pretty much any other speaker

created....the frequency response is already flat which means you don't

need an amp that inherantly boosts at impedance peaks. And on another side note, no matter

how you look at it, his speakers have a failing low frequency response

and the EQ being implemented by the wierd amp/speaker interaction is

absolutely no different than EQ being implemented in front of a voltage

source amplifier. For the same flattening of response, you're going to

have all the same phase changes that he complains about. It's just like the constant EQ required for the tweeter in the Jubilee. It's identical to the effects achieved by collapsing the vertical polars - only you've got different compromises involved.

For anyone interested this is a more standared view about Amplifier Output Impedance goals for loudspeakers designed with this in mind. This has a model that helps to show what Mike has been saying. Tube Amplifiers definitly can alter the sound of a speaker tonally whether we like it for the better or worse.

http://www.transcendentsound.com/amplifier_output_impedance.htm

Ok, now you're confusing me cuz that article is portraying exactly what I'm trying to say, lol. Allow me to highlite the part where he mentions that speakers are NOT constant power devices. Their efficiency changes with frequency. (and that change is a lot greater than the ripple you see in the frequency response).

[kaiser SET say]

"Ya' know, I could lend you a proper tube amplifier." Priceless[]

[Trey Cannon]

Mike, yes, I'm still using the Super-T.

Dean,

Ya' know, I could lend you a proper tube amplifier. []

Is there such a thing?[6]

[Deang]

Now Robert, are you putting the gnostic squeeze on me again. I have to take a break from them for a while, probably for a year or two. I may or may not go back to them, though a Merlin is definitely in the picture. Tube amps on open racks with one and three year olds in a busy room don't mix. In the meantime, I'll enjoy the things chip amps bring to the table.

[Trey Cannon]

here is a Proper Tube Amplifier

[anarchist]

Understood, I just keep the kids out of my room. They know not to touch my amps. My lil one is 2 1/2 with another one on the way.

Get an Eico. No worries and nothing for the kids to touch. I wonder just how great is would sound on your Jubs - it sounds awesome on Khorns and Heresies.

[mikebse2a3]

No offense Mike, but that article is full of "audiophile magic" and ...not sure if I'm qualified to say that or not, but I've got a textbook here that disagrees with about every side point he makes. For what it's worth, it's actually easier to build current sources (especially with solid state), which makes it seem odd when he keeps referring to the "SS of the 60's". Nevertheless, though he doesn't state it explicitly, he is taking advantage of the non-linear characteristics of his amp to boost the low-end on his speakers that need a ton of boosting in the low end (the same rising output with a rising impedance problem). I guess you could just say it's convenient that he's got a rising impedance as the frequency goes down. But frequency response doesn't tell the whole story and I can attest to the fact that the speakers to which he refers sound like complete garbage (which is gonna be due to all sorts of other things you can measure).

Mike you might want to research Nelson Pass's work history before you pass judgement to quickly. Pass is a very well respected amplifier designer and inventor. He has experience designing and building all types of amplifiers and as a matter of fact he designed Threshold Amplifiers which were very High Quality Amplifiers that would have exhibited excellent voltage source characteristics and were used in many high quality studio applications. He invented the Stasis Topology which was used by Threshold as well as liscensed it to Nakamichi many years ago. What he is explaining in this article is how the natural characteristics of these drivers actually benefit from the natural characteristics of this type amplifier(ie: current source type). And yes Mike what he is pointing out in this article is when these drivers are used with a Constant Voltage Type Amplifier they will be disappointing but when driven with an amplifier design that meets their requirements their full potential can become realized.

"I guess you could just say it's convenient that he's got a rising impedance as the frequency goes down"

It's not convient Mike but as I'm sure you know is the normal characteristic of a moving coil driver to have a rising impedenance as the driver/system nears it's resonant frequency as well as normal to have a rising impedance as the frequency increases also.

Ok, now you're confusing me cuz that article is portraying exactly what I'm trying to say, lol. Allow me to highlite the part where he mentions that speakers are NOT constant power devices. Their efficiency changes with frequency. (and that change is a lot greater than the ripple you see in the frequency response).

[] That was the point of posting it Mike because it had a good model to explain things you were saying also.

I guess when all is said and done I'm not convinced that just because a driver has an increased voltage on it's terminals that, because it is an (electro to mechanical to acoustical) conversion device which is imperfect in the real world, it will always corelate to an increased acoustical output. Roy how about explaining this so that I can understand these relationships better and feel free to use as many words as you need!!![]

Anyway Dean and Roy sorry for getting off track from this thread!

mike tn[]

[Guest " "]

"Tube amps on open racks with one and three year olds in a busy room don't mix"

Get some cages....

For the tube amps....not the one and three year olds.

[Audible Nectar]

"Tube amps on open racks with one and three year olds in a busy room don't mix"

Get some cages....

For the tube amps....not the one and three year olds.

BWAHAHAHAHAHAHA!!!!! That's a hoot!!!

[DrWho]

Mike you might want to research Nelson Pass's work history before you pass judgement to quickly...

What he is explaining in this article is how the natural characteristics of these drivers actually benefit from the natural characteristics of this type amplifier(ie: current source type). And yes Mike what he is pointing out in this article is when these drivers are used with a Constant Voltage Type Amplifier they will be disappointing but when driven with an amplifier design that meets their requirements their full potential can become realized.

Ya, I know of his work, but this specific article was hardly "technical" and full of all sorts of marketing garbage that caters to the audiophile crowd. Really the only thing that can be gleaned from the examples in the article is that a current source amplifier works "well" with speakers that have a dropping output with an increasing impedance. But you simply cannot use the same amplifier topology with a system that doesn't drop in output where the impedance rises (whether or not the Jubilee fits into that category is another issue...). And you certainly shouldn't only be looking at the frequency domain either - talk about a limited perspective on the performance of anything.

I guess when all is said and done I'm not convinced that just because a driver has an increased voltage on it's terminals that, because it is an (electro to mechanical to acoustical) conversion device which is imperfect in the real world, it will always corelate to an increased acoustical output.

Have you ever observed a single case where increasing the voltage at the speaker terminals reduced the output of the driver? Or how bout decreasing the voltage to increase the output? If not, what electro-mechanic-acoustical model exists that supports your theory? What you propose is entirely impossible since it would follow that such a system would produce output when decreasing the voltage to 0V. It would also follow that such a system would require an infinite amount of voltage to turn it off.

[Deang]

I kind of like the idea of cages for the kids. Most of the gear I like doesn't come with cage(s), and the ones that do cost too much -- even so, cages get pretty damn hot too. The real problem is that I'm here by myself with three of them most nights, and I can't be everywhere at once. Temple's room is upstairs joined to mine, and the two little ones like to hang out with her when she's up there -- we're talking 6, 3, and 1 here, and I can't be up there with them when I have things downstairs to do. If they wanted to watch a movie, I would have to power everything up and basically hang out and suffer through a movie I've seen at least a hundred times because I couldn't leave them unsupervised around the stuff. If I happened to not power things up early -- most of my listening isn't done until after they go to sleep, so I wouldn't power them up until 10 at night, and then had a choice of forcing myself out of the chair to shut them down before I passed out, or leaving them on all night and shutting down in the morning. The whole thing was turning into a kind of bizarre exercise, and after Deb went back to work, I started to see the tube thing in a whole new light -- a major pain in the rear. If I didn't think that what I was hearing now was an acceptable substitute, I would have continued on with the hassle. Finally, and I'm very serious about this (said with my best serious face) -- better horns and drivers do more for the sound than any damn amp. I've said that more than once, and experiences of late continue to support it.

[Duke Spinner]

- better horns and drivers do more for the sound than any damn amp. .

[]

[Guest " "]

"we're talking 6, 3, and 1 "

I'm starting to feel my age....mine are 17, 19, 21

I don't have to worry about them getting burned on tube gear...but it would be nice to get thru a month with out a new tranny, body work, window repairs, rims that need straightening, oh, and my favorite..lets leave some boxes behind the convertables rear seat and try to roll back the top...did you say snap crackle pop on a rear window.

[Deang]

"...better horns and drivers do more for the sound than any damn amp."

I do want to put that statement in the context of amps that sound good just different -- a hashy sounding amp will sound like 50 grit sandpaper on a revealing system.

I've been looking down the road and seeing that stuff coming Fritz. I'm 48, and unless I get my act together I won't see Alexia graduate from High School. I'm getting ready to quit smoking and get back into shape -- I have to last at least another 40 years.

[anarchist]

Thank you Dean-O. I was feeling fairly old to be having a new baby... but I am having mine a good 6 years younger than you were. Whoo hoo!

I am also on the quit smoking trail... just haven't arrived at the destination yet.

[bodcaw boy]

hey deano and anary,

i have a grandson that is 5 days old!! quit smoking about 6 years ago. oh......how about the jubs?

have a blessed day,

abuelito roy