Tweeter question

[Coytee]

Where is Clarence when we need him?

[:^)]

[ZAKO]

He,s laying on the floor of the anechoic chamber bleedind at the ears.

[Coytee]

He,s laying on the floor of the anechoic chamber bleedind at the ears.

oh, ok... I thought that was Roy with BBQ all over his face...

[]

[bodcaw boy]

There is no inherent relationship between efficiency and distortion.

jw

there is an inverse transfer function between efficiency and distortion in a given acoustic system.

Roy,

We need to be careful on this.

On a "given system" there is only one efficiency and there is only one distortion. I believe the function requires that you look across various systems. This is more than a question of semantics. I don't dispute that the relation (in this case a correlation) is probably true. But you are now implying a mechanism. But really, any system can be driven into a non-linear range.

Gee, maybe I should let John speak for himself .....

-Tom

[bodcaw boy]

[]

There is no inherent relationship between efficiency and distortion.

jw

there is an inverse transfer function between efficiency and distortion in a given acoustic system.

Roy,

We need to be careful on this.

On a "given system" there is only one efficiency and there is only one distortion. I believe the function requires that you look across various systems. This is more than a question of semantics. I don't dispute that the relation (in this case a correlation) is probably true. But you are now implying a mechanism. But really, any system can be driven into a non-linear range.

Gee, maybe I should let John speak for himself .....

-Tom

okay....this....is ......me.....being......real......careful........[]

actually, we have been thru that exercise quite a bit and as long as we are talking about loudspeakers, then there is a relationship between efficiency and distortion. you are correct, any system can be driven into its nonlinear range......the difference at what input level.....if spl levels are important to you then you might want the spl to be high before, say, distortion is 1% or more. if a system measures 100dB at that distortion level and another measaure 94 dB at that distortion level, by definition (output/input), the louder system is efficient (also spl increases are not always a measure of efficiency but all things being equal, it can be a measure along with other data). that is the way we measure it. now where the gain comes from is another story..........................

roy delgado

[bodcaw boy]

Well, theres a lot going on here!<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Roy-

I can only assume that the relationship you cite between efficiency and distortion is for a given horn configuration loaded using different drivers or alternatively a common driver loaded into different horn configurations. Thus, from a series of experiments, the functional relationship can be developed. This, at least in my minds eye, is not what I would consider an inherent relationship.

then what would you call it? you take the a driver (high impedance source) and it load directly to the air (low impedance). that by definiton is an inherent relationship and a bad impedance match to boot. put a transformer in front (why say do we have one of them.......a horn maybe) and the power transfer goes up. and funny thing, so does efficiency as the horn allows the driver to better match the air. can't get anymore intimate than that....

I consider an inherent distortion relationship the relationship between, say, excursion and distortion. As one goes up, so too, the other. In this embodiment, the system is established.

Also, when I examine Smalls relationship for electro-acoustic efficiency, its made up of linear terms (B, l, Sd, Re). The terms that account for loudspeaker distortion are non-linear (suspension compliance, axial magnetic flux anomalies and few others).

Having said all that, I do not see an "inherent" relationship between efficiency and distortion (at least that's what I was trying to get at).

jw

sorry i disagree. whatever words you use, i can take a driver (any driver) and by horn loading correctly, i can increase it's effciency by using a well designed horn.

roy delgado

[bodcaw boy]

Are the operative words "in a given acoustic system" the key. That would say that any change in drivers, driver function such as voice coil, cone, etc, would change the given acoustic system. So am I missing something if I say that the theory is correct but the actual ability to implement the theory is the next to impossible part? This is why John's remark about the relationship between efficiency and distortion is wrong because you have to change the "acoustic system". There are many very low distortion lower efficiency speaker systems available. Sorry but just trying to understand where theory intersects with the real physical world.

what is the definiton of efficiency? in my world, warped at best, output/input. how much input does it require to an output? it would be nice if both output and input could be measured in the same values, say like watts. so we have acoustic watts/electrical watts. that percentage is an efficiency number. if you use distortion as a gauge then low distortion, low efficiency systems will generate low acoustic watts and therefore, in most instances, low spl. basically what horns can give is an efficiency increase so that a larger dynamic range can be attained before we reach a set distortion level. a system or a component of a system can be designed to be more efficient. some woofers are more efficient than another. some horns are more efficient than others. some amps are more efficient than others. so it can be practically applied.

roy delgado

[D-MAN]

There is no fixed mathematical ratio, if that's what is implied, however, there is ABSOLUTELY a GENERAL inverse relationship between distortion (IM distortion, in particular) and efficiency, which everyone can easily experience. However, no mathematical formula will provide this, but that doesn't mean that the PRINCIPLE is not true.

The written account of this is one of PWK's legacies, mentioned in professional papers, patents, and also by different respected authors.

DM

[John Warren]

Horn loading increases efficiency at a significant debit to bandwidth and when bandwidth goes down so too does transient behavior because bandwidth and transient behavior are orthogonal views of the same thing. Look at the K33E, in the Klipshorn the bandwidth is 40-400Hz, in a vented box it would be 40-800Hz a full octave higher in bandwidth. Sure I loose 6 or 7dB/W sensitivity but I get improved transient behavior. And I will state it again, horn loading reduces bandwidth and thus reduces transient behavior. This is a consequence of the efficiency/bandwidth/enclosure relationship.

I disagree with Roy, I do not think that efficiency gives some indication of distortion. A "correlation" as Tom so aptly stated it, is all that the distortion vs. efficency relationship that Roy describes is.

Look at it this way, If I have a system in my living room that has 1% efficiency that tells me NOTHING about how much distortion it will produce. All I know is that it will play real loud with a 100W amplifier.

Who do I give my "resignation" to?

jw

edit-

the spl vs distortion measurements that Roy described makes perfect sense and I can see how an relationship (though empirical) can be established from that measurememt. What I'm saying is given two systems with different efficiencies one cannot assume the system with higher efficiency will, by default, have lower distortion.

[DrWho]

Look at the K33E, in the Klipshorn the bandwidth is 40-400Hz, in a vented box it would be 40-800Hz a full octave higher in bandwidth. Sure I loose 6 or 7dB/W sensitivity but I get improved transient behavior. And I will state it again, horn loading reduces bandwidth and thus reduces transient behavior. This is a consequence of the efficiency/bandwidth/enclosure relationship.

But once you add the squaker/tweeter you regain the transient behavior (since the total frequency response of both systems is going to be similar). But I think the khorn wins out because it will exhibit less power compression???

[bodcaw boy]

Horn loading increases efficiency at a significant debit to bandwidth and when bandwidth goes down so too does transient behavior because bandwidth and transient behavior are orthogonal views of the same thing. Look at the K33E, in the Klipshorn the bandwidth is 40-400Hz, in a vented box it would be 40-800Hz a full octave higher in bandwidth. Sure I loose 6 or 7dB/W sensitivity but I get improved transient behavior. And I will state it again, horn loading reduces bandwidth and thus reduces transient behavior. This is a consequence of the efficiency/bandwidth/enclosure relationship.

sorry, i disagree again. the top end is limited in a khorn lf because of path length differences. in a straight horn, it can most certainly go out as far as the driver will go. and as for transient behavior, as the diaphragm moves less for same given spl, the transients will be more behaved because the diaphragm is not having to overcome its own mass as much because Xmax has been reduced. there is a relationship between eff/bandwidth but is above and beyond the simple efficiency gain by just placing a good ole horn in front of a diaphragm; effciency/bandwidth is what is to be gained in the different types (variables) in horn design.

I disagree with Roy, I do not think that efficiency gives some indication of distortion. A "correlation" as Tom so aptly stated it, is all that the distortion vs. efficency relationship that Roy describes is.

sorry. i can give you a simple example, that paul used to use. a 4" bose driver curved as a direct radiator; that same driver behind a good horn, spl up; efficiency up; distortion down; same given spl.

Look at it this way, If I have a system in my living room that has 1% efficiency that tells me NOTHING about how much distortion it will produce. All I know is that it will play real loud with a 100W amplifier.

i agree; more info is needed. what is the sensitivity; polar pattern, what kind of horn, and how much distortion is present at a 100W input? sometimes distortion is desirable; emergency sirens for instance but if you want the output to be as close to the input as possible, having a driver behind a horn will get you closer than just a driver.

Who do I give my "resignation" to?

jw

edit-

the spl vs distortion measurements that Roy described makes perfect sense and I can see how an relationship (though empirical) can be established from that measurememt. What I'm saying is given two systems with different efficiencies one cannot assume the system with higher efficiency will, by default, have lower distortion.

will you still send flowers?

roy delgado

[linkalley]

"sorry. i can give you a simple example, that paul used to use. a 4" bose driver curved as a direct radiator; that same driver behind a good horn, spl up; efficiency down; distortion down; same given spl." hey roy! i think you mean efficiency up, not down??

maron will attest i am from ok land but please correct me if i am wrong[] even dr. bruce edgar will agree with pwk statement. i think i am getting it??

[John Warren]

> The mass corner for a horn loaded driver is = 2Fs/Qts per Keele (straight horn). For the K33E this is ~200Hz(?).

> Transient behavior is determined by bandwidth, more octaves of bandwidth, better transient behavior. Who cares what the cone is doing?, what's the bandwidth.

I never stated that there was not a casual relationship between efficiency and distortion. But the fact of the matter is that distortion is consequence on non-linear behavior. Efficiency is determined from linear terms. There is no direct relationship that can be established between the two thus it's left largely to empirical observations.

jw

[boom3]

> The mass corner for a horn loaded driver is = 2Fs/Qts per Keele (straight horn). For the K33E this is ~200Hz(?).

> Transient behavior is determined by bandwidth, more octaves of bandwidth, better transient behavior. Who cares what the cone is doing?, what's the bandwidth.

I never stated that there was not a casual relationship between efficiency and distortion. But the fact of the matter is that distortion is consequence on non-linear behavior. Efficiency is determined from linear terms. There is no direct relationship that can be established between the two thus it's left largely to empirical observations.

jw

In support of John:

As we say in the social sciences, correlation is not causation.

[DrWho]

> The mass corner for a horn loaded driver is = 2Fs/Qts per Keele (straight horn). For the K33E this is ~200Hz(?).

> Transient behavior is determined by bandwidth, more octaves of bandwidth, better transient behavior. Who cares what the cone is doing?, what's the bandwidth.

I never stated that there was not a casual relationship between efficiency and distortion. But the fact of the matter is that distortion is consequence on non-linear behavior. Efficiency is determined from linear terms. There is no direct relationship that can be established between the two thus it's left largely to empirical observations.

Doesn't transient behavior return when you add the rest of the frequency bandwidth of the system? Or is there something inherant to the limited bandwidth of each section that reduces the overall transient behavior of the system? I would think the total frequency response of the system is what determines the total transient behavior...

Trying to be practical, if there is no direct relationship, then that should mean there exists some lower efficiency systems that have less distortion? I've long struggled with this concept and would love to see some of the systems at play that can reduce distortions without increasing efficiency. I've never liked the idea that "louder is better" (but that's ultimately the conclusion klipsch has come to).

[kaiser SET say]

Now I'm confused, is casual not a relationship? You can't have it both ways either you agree there is a relationship between the two or you don't! It sounded to me like you protested the two did not have relationship and then you turn around 2 pages later and admit to a relationship but only casual[]

[boom3]

Now I'm confused, is casual not a relationship? You can't have it both ways either you agree there is a relationship between the two or you don't! It sounded to me like you protested the two did not have relationship and then you turn around 2 pages later and admit to a relationship but only casual[]

Casual is ar happenstance relationship between two events, such as me and a co-worker wearing blue shirts on the same day.

Causal means one event causes another.

I must stress that we all need to use the same frame of reference to make this meaningful and not sophomoric. Every transducer has an irreducible level of distortion inherent in its design and construction. Distortion increases with increasing output level. It is entirely possibly that a direct radiator could start out with a lower level of distortion at, say, 80 dB than a horn. A well-designed horn will have a lower level of distortion at say, 100dB, where the direct radiator's distortion may be intolerable. As Paul observed (paraphrase) acoustic suspension speakers go from fine to gross distortion in the difference between 'background' music levels to levels approaching live performance.

[ZAKO]

You can have a casual drink and not get drunk......I love Roys casual diplomacy....He,s been putting notch,s in Warren,s ears without him noticeing. This is a great thread.

[Deang]

LOL! Yeah, but do we call them notches or traps?

Yes, it is a great thread. What's scaring me is that I understand what John is trying to say. I don't think that's ever happened before.

[John Warren]

And let's keep it going...

In Roy's earlier example he considered two systems X and Y. The task is to determine the efficiency at the SPL where each has reached a distortion level of 1%. So how do you do it? You cant calculate it. You have to physically go and measure each one because you dont know when the system under test is going to go non-linear (i.e. distort) as a function of input power. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

When you do the tests you see that there is a relationship between the distortion measured and the efficiency calculated at the SPL required to achieve 1% distortion. There is a relationship yes BUT it is associated with the factors that contribute to distortion which are non-linear. You can't, using the physics, determine the result (say 1% distortion target).

Let the arrows fly!

jw