Measuring Raal 140-15D

[r-carpenter]

Ho-Ho-Ho

[r-carpenter]

No, but really, I finally have a pair in my possession for a week or two.
There was also a 70-10 OEM which I will describe but because it's OEM and the owner asked me not to, I will not post the data on OEM.
First impressions are. Drivers are build like tanks. Huge transformers. Very heavy. Face plate is thin but sturdy and I am guessing, surface mounting should be just fine. The gaskets are made from cork. I guess that's fine too.
We did a quick set of measurements of both drivers. Because it was exactly that, a "quick" set, I will re-measure sometime next week.
First impressions are.
140-15 has one of the best horizontal off axis performance I've seen AND one of the worst vertical off axis performance I've seen. Use of a foam pads negates the vertical issues but even with pads it's very bad. Horizontal dispersion is not affected by use of foam pads.
Without foam pads, on axis response is nowhere near as flat as Raal suggests. With the pads, it levels out considerably, however top octave is rolled off. Starting from about 13k it drops by 5db. Not great in my book but again, I will re-do everything to be sure.
Impedance is almost ruler flat.
Distortion character is interesting. Low high order distortions and stable 2nd order throughout the range.
I would say that usable range, based on non linear is 2500hz and up with high order electrical crossover network.
CSD is good with small ringing present in the 2k area.

Smaller OEM version had better on and off axis response. It had worst CSD with pronounced ringing around 2K. Looks like it is also limited to 2500hz with better polar response. Smaller OEM version of 70-10 also sounded less efficient compare to a larger 140-15D.

The thread is about driver performance not "oh how I love it".
I will start posting data next week.
If there are any test you would like me to run (gating, terminal voltage and so on) pleas let me know.

[gregbegland]

Do you mean 70-20? That's the OEM.... 70-10 is the standard that anyone can purchase.

[r-carpenter]

OEM version that looked like 70-10. I guess that would be a 70-20 then.

[r-carpenter]

I've decided to look at the performance without foam pads first. Also, started with positioning the microphone about 4" away, centered.
CSD shows a bit of ringing which is probably rear chamber? Founteks and AC have similar resonances.
All measurements are done with 30mfd in series.

[r-carpenter]

now the Mic is moved to 23cm away from the driver

[r-carpenter]

now we are at 1m.
FR and distortions are also done in ARTA. I don't use ARTA often and didn't input microphone correction file. Also, note, ARTA FR has 10db steps not 5db like SE.

[r-carpenter]

distortions in Sound Easy, taken from about 15cm, 1.6v and 2.83v
at 1.6v driver was averaging 91-92db of SPL according to my $50 spl meter.

Next, I'll be looking in to polar. Stay tuned.
Love the tags! All tho one with aaaaaaaaa is getting old.

[ErinH]

I may be the only person here to request this, but I'll do it anyway...

Do you have a way to measure the driver with a higher value cap (or just no cap at all) so you can go lower in response? I seem to remember the RAAL's having a rising response and it's hard for me to discern if the rising response here is influenced by the use of a cap.
I did the math, and it looks like the crossover point is 650hz.
A low output test at 1m would suffice. The FR shouldn't change significantly unless you're comparing very low output to very high output and even still it won't be enough for most of us to care.

Edit: nevermind about se hd.
Have you tried extending your bandpass on the HD sweep? You may get different results by exciting the driver at a lower tone than 1khz. I've seen it happen in stranger situations.


Thanks!

[r-carpenter]

I may be the only person here to request this, but I'll do it anyway...

Do you have a way to measure the driver with a higher value cap (or just no cap at all) so you can go lower in response? I seem to remember the RAAL's having a rising response and it's hard for me to discern if the rising response here is influenced by the use of a cap.
I did the math, and it looks like the crossover point is 650hz.
A low output test at 1m would suffice. The FR shouldn't change significantly unless you're comparing very low output to very high output and even still it won't be enough for most of us to care.

Edit: nevermind about se hd.
Have you tried extending your bandpass on the HD sweep? You may get different results by exciting the driver at a lower tone than 1khz. I've seen it happen in stranger situations.


Thanks!

No problem. I may be conservative with voltage because it's not my driver but sure.
I don't think rising response is affected by the capacitor. The testing started without foam pads which are designed to shelve the response. Let's see.
Crossover with 30mfd (actually 33) is visible from impedance. I can also run analog impedance sweep starting from whatever I choose.

[ErinH]

Thanks.

[r-carpenter]

actually, I think doing an analog impedance sweep from 300hz up would be a great idea. Ribbon has to have a "string" resonance down low.

[Pete Schumacher ®]

actually, I think doing an analog impedance sweep from 300hz up would be a great idea. Ribbon has to have a "string" resonance down low.

You won't get any results that matter, since the transformer dominates at the low frequencies. Basically, it acts as a HP filter.

I actually drove the 70-10D directly from the woofer XO one time, at significant power levels. Didn't bother it one little bit and once connected properly, performed exactly like before.

Built like a tank? Yes indeed.

[Ron_E]

No problem. I may be conservative with voltage because it's not my driver but sure.
I don't think rising response is affected by the capacitor. The testing started without foam pads which are designed to shelve the response. Let's see.
Crossover with 30mfd (actually 33) is visible from impedance. I can also run analog impedance sweep starting from whatever I choose.

If you're using SE and put the reference probe after the cap you'll get the response of the tweeter all by itself.

Ron

[MSaturn]

Well, if the neoX 2.0 performs like this, my planned usage will be golden. I think it might actually perform better.

[exojam]

RC,

Since you are looking at how the tweeter measures with (and without) the pads, I thought you may like to see this.

It is just two screen shots Dennis M shows concerning the pads with the Raal in his speakers.

http://www.avsforum.com/avs-vb/showp...&postcount=791

Just posting this in case you maybe interested.

James

[DoubleTap]

Hey Roman, the 140-15 and 70-10 both are designed to be used with the foam pads ... why would you take data without them? That said, something doesn't look right about your data. Without the foam pads the top end should RISE significantly. To see the top end drop like you have, that's how it should look with the foam pads on and closer together than intended.

I've measured one or two, and that's always how it works.

[r-carpenter]

This is an analog impedance sweep starting from 200hz. No cap was used and voltage was around 0.5v

[r-carpenter]

This is the effect of the foam pads. First graph shows the response on axis 1m without the pads (top) and then with the pads spaced on the ends, closer to the center and finally in the position Raal recommends.
Second Graph shows the response without the pads and with the pads in the recommended position.
Third graph shows on axis response with the pads in the recommended position.

[r-carpenter]

As requested by ErinH, distortion sweeps WITHOUT the capacitor.
I started with 0.55v at 400hz. Didn't want to stress the $700 driver that does not belong to me.
second sweep was started at 600hz at a higher voltage.
These were done with foam pads ON.