K510 Jubilee little HF horn....

[sfogg]

John,

Yup, I considered the Radian as well. The spec sheet looks good on it but I saw a post either on AA or the Lansing site from a guy that measured the 850 and basically said it was the worst 2" driver he had ever measured. As such I crossed that one off the list.

Had to make some cables tonight to be able to hook up another EQ/crossover to do some EQ work with the K510/Peavey which I can hopefully work on tomorrow. After I get the CD EQ and some contouring done I am planning on wiring it into the system hooked into my QSC ABX box so I can switch between both horn/driver combos on the fly (in mono since I only have the one Peavey) to hear the K510/Peavey and existing setup truely back to back.

I also want to do some slower sweeps at higher power to look for resonances and such and maybe THD tests and some waterfall plots if my laptop stops acting up. Fun fun fun!

Shawn

[PrestonTom]

Shawn,

Keep up the good work!

Are you going to be able to measure the the K510 with a Klipsch driver (or even a B&C which I beleive is what Klipsch is using, although who knows what additional additional things went into it when a large company orders in volume).

Thanks for sharing the info,

-Tom

[sfogg]

Hi Tom,

AFAIK Klipsch uses the K69 and the B&C DE75 on this horn. I don't have either driver so the only way for me to measure one would be to order a B&C. According to B&Cs site the DE75 is discontinued and I think it was replaced with the DE750 which is also discontinued and likely replaced by the DE750tn. It would be interesting to have another 2" driver to compare the Peavey against but I'm not sure I want to order something else unless the Peavey starts to look like a bad choice since they all cost $200-$300 a pop and I'm going to need two more for the L/C/Rs. So unless curiosity gets the better of me, which is why I have the K510s in the first place , I'll be working with just the Peavey for now. And when the throat adapters come in I can also try the Altec 902 and a 288-8k on the K510 as well.

Also... I'm sure Roy has far better measurements of the K69 and the B&C on the K510 then I could make. Likely he has a little bigger budget then I do.

Shawn

[bhendrix]

A little off topic, but could the K510 be used with a K-55 driver and replace the K-600 in the Cornwall?

[DrWho]

Not without an adaptor. The K55 is a 1.4" throat and the K510 is 2". However, there are plenty of inexpensive 2" drivers that would work real well in a 3-Way Cornwall application.

I'm very interested to see how well they work out as a 2-way...but then you're talking a sound very similar to that of the Reference lineup []

Is the "sensitivity" of a Constant Directivity horn based on its output at the bottom of its response (say 600Hz in the case of the 510), or the output at the top end of its response (18kHz or whatever you choose for the HF extension)?

[PrestonTom]

Hi Tom,

AFAIK Klipsch uses the K69 and the B&C DE75 on this horn. I don't have either driver so the only way for me to measure one would be to order a B&C. According to B&Cs site the DE75 is discontinued and I think it was replaced with the DE750 which is also discontinued and likely replaced by the DE750tn. It would be interesting to have another 2" driver to compare the Peavey against but I'm not sure I want to order something else unless the Peavey starts to look like a bad choice since they all cost $200-$300 a pop and I'm going to need two more for the L/C/Rs. So unless curiosity gets the better of me, which is why I have the K510s in the first place , I'll be working with just the Peavey for now. And when the throat adapters come in I can also try the Altec 902 and a 288-8k on the K510 as well.

Also... I'm sure Roy has far better measurements of the K69 and the B&C on the K510 then I could make. Likely he has a little bigger budget then I do.

Shawn

Shawn,

It is always easy for me to spend someone elses money. When you then muliply by 3 (cabinets), it does add up. The 902s will be an interesting possibility; however, I thought there was a problem using a smaller throat on a driver (1inch on the 901) to a larger, 2in throat in the horn (K510).

Good Luck,

-Tom

[sfogg]

"A little off topic, but could the K510 be used with a K-55 driver and replace the K-600 in the Cornwall?"

Not sure it would fit with the required adapter for the K55. It would also take a new crossover to apply any EQ required by the CD nature of the horn with the K55. Since the K55 poops out pretty good on the top end I'm not sure this would be worth the effort. If you were going to go through the hassle on fitting the K510 and working out a new crossover I'd go with a better driver on the K510 at the same time and potentially go two way with it or if I were going to leave it three way cross over to the tweeter higher.

Shawn

[sfogg]

"Is the "sensitivity" of a Constant Directivity horn based on its output
at the bottom of its response (say 600Hz in the case of the 510), or
the output at the top end of its response (18kHz or whatever you choose
for the HF extension)?"

Pretty sure by itself a CD horn has no sensitivity.

I
don't think I have seen drivers specced for efficiency taking into
account a CD horn. They are usually speced on an exponential or plane
wave tube. Or perhaps specced at 1kHz or something below where the
driver is rolling off on a CD horn.

Shawn

[sfogg]

Tom,

If you are going to spend my money at least do it with some flair... think TAD 4001, JBL 435Be or something like that.

Don't get me wrong, I'd be interested in seeing what the Klipsch/B&C (or the TAD or JBL) could do too. That would give me a better idea on where the Peavey is as well. If I had unlimited funds I'd buy a bunch of 2" drivers and go to town with them. The adapters will at least let me compare the Peavey to more or less know quantities in the Altecs.

"The 902s will be an interesting possibility; however, I thought there was a problem using a smaller throat on a driver (1inch on the 901) to a larger, 2in throat in the horn (K510)."

Throat adapters can cause problems. I think diffractions and reduction of the HF response. A fair number of the 2" drivers in effect have built in throat adapters. Some of the larger JBLs are around 1.5" at the start of their throat and flare out to 2" where they bolt to a horn. I think the 2446 is like this for example. From what I have read the 2447 is basically a 2446 but without the throat extension so it is a 1.5" exit driver. That results in the phase plug being very close to the entrance of the horn... JBL calls those an optimized aperture driver I think.

The Peavey is like this too with the main difference being the user can use or not use the adapter. Without the factory adapter it is a 1.6" exit driver with the exit much closer to the phase plug then when used with 2" horns. Hopefully the engineering at Peavey at least tried to account for the adapter somewhat in the design.

Shawn

[DrWho]

"Is the "sensitivity" of a Constant Directivity horn based on its output

at the bottom of its response (say 600Hz in the case of the 510), or

the output at the top end of its response (18kHz or whatever you choose

for the HF extension)?"

Pretty sure by itself a CD horn has no sensitivity.

I

don't think I have seen drivers specced for efficiency taking into

account a CD horn. They are usually speced on an exponential or plane

wave tube. Or perhaps specced at 1kHz or something below where the

driver is rolling off on a CD horn.

Shawn

I guess my question is how loud will the output be at 1 meter with 2.83V across the motor at 20kHz [] I have a hard time believing it's going to be much over 90dB, even with 113dB on a plane wave. I dunno.

[TBrennan]

"The K55 is a 1.4" throat and the K510 is 2"."

I think the K-55 is 1" screw-on. 1.4" is the 4-bolt large format Altec, the 288 and such.

[TBrennan]

Shawn---Most compression drivers have an inside flare rate of 200hz or so, it goes back to WE days. Thus most horn-drivers combinations will have a flare rate discontinuity at the driver to horn junction. Experience seems to show that such discontinuity is a minor problem if one at all. Not if one is necking down though, only when expanding, necking down causes serious response errors.

The adapters I've used (and those I've examined) seem to follow the driver flare rate so the discontinuity would come at the adapter to horn junction rather than the driver to adapter one.

[sfogg]

Here is an interesting twist.....

I setup the equipment for real tonight to start working with the EQ for the Peavey. Now I'm using the broadband noise source in my Spectral Dynamics FFT which is what I'm analyzing the measurements with. The noise source is fed to the Behringer DCX-2496. From there it feeds a stock Teac tripath amp and from there that is driving the Peavey. As I mentioned in the earlier pictures the Peavey was driven directly from the noise source in my Audio Control SA-3051 RTA.

I put a high pass crossover in place at 300hz in the Behringer (just to avoid running it full range in all the tests) and then did a test measurement to get a baseline for starting the EQ. This is to 20kHz and is attached here.

Compare this to the 20kHz measurement from yesterday.

Notice any differences?

The measurement tonight has better HF response. I'll measure/calculate it to be sure but I am assuming the SA-3051s noise source has a pretty high output impedance and it is interacting with the Peavey which is altering the FR. The Teac should have a low output impedance and it wouldn't be as effected as varying impedance of a driver.

This is the difference between measuring FR into something simple like a non-inductive resistor and measuring a real speaker. Also why low output impedance is a good thing in an amp... or a very flat impedance presented to an amp.

So... in a nutshell ignore all the pictures from yesterday. Unless you are a high output impedance amp user.

Back to the bench....

Shawn

[sfogg]

OK...getting down to business now. This is with a 6dB/octave high shelving filter in place at 20kHz with 15dB of gain.

Top end at 2kHz...

[sfogg]

Scale extended to 4kHz...

[sfogg]

Scale out to 10kHz...

[sfogg]

Scale out to 20kHz....

[sfogg]

Still to 20kHz but now with a touch of parametric EQ applied..

-3dB @ 14.8kHz Q 10

[sfogg]

Additional EQ -2dB @ 12.5 kHz Q 10

[sfogg]

-3 dB @ 18.8kHz Q10