RS52 tests and tweaks

[Landroval]

Oh, nice.. The RS90 sounds cool. Pity shipping from US is quite expensive (at least what PE uses).

[WillyD]

there is no such thing as the RS15 on PE's website. why would anyone make a 15mm tweeter? it would be too small to have low distortion.

I am almost certain that he was speaking of the Reference 15" subwoofer. :W

[dwk]

Looks like I've got a pair on the way, results posted shortly.

John

Cool - I'm very interested to see how my measurements correlate to your more controlled setup.
BTW - I didn't mean to exclued you from the offer above, I just forgot you post here too.
OTOH, I implore you to refrain from publishing any more info on the RS90 - I *really* dont need any more distractions. (anyone want to buy 4pcs HiVi BS3N?)

[jkrutke]

Here's a quick request for one of you guys that has your RS52's cut open. (DLR, fsmidt) Any chance of getting T/S parameters for this dome? This can probably be done delta compliance with the back off. Get the free air impedance curve, measure the cup's volume, (with liquid maybe?) put the cup back on and get the delta impedance. The reason this might be usefull is to do some excursion modeling.

The ones I tested aren't mine to cut open, and even if they were, I couldn't bring myself to mutilate them.

Excursion modeling will help select a crossover point. I've completed testing the RS52, and I can say that distortion is low enough through the low end that in most cases the dome will run out of Xmax before distortion becomes a problem. This dome seems like a big version of a 27TBFCG - no distortion down low, and how low you cross just depends on how loud you play it.

I've got another dome to test before I post the results. The RS52's are now on their way to Mark K.

[dwk]

Excursion modeling will help select a crossover point.

Did anything in your tests support/refute Darrens 0.75mm estimate?

Good news on the distortion - good to know that my tests weren't completely out to lunch. I'm looking forward to seeing your test results - I kinda hope the 'other dome' is the mdm55, since that is the obvious competitor for the RS52.

[KSA]

Not sure these parameters are 100% accurate, they are based on some impendance measurements i did a couple of weeks ago. I still have an open rs52 somewhere, so i can measure it again in the weekend.

* Loudspeaker Measurement System
* LMS(TM) 4.5.0.352 jul.01.2005
* (C)opyright 1993-2000 by LinearX Systems Inc
* Electro Mechanical Parameters
* Jun 14, 2006 Wed 2:37 pm
* Library=rs52 imp.lib
* Reference Curve=Sweep
* Delta M/C Curve=Sweep
* Method= Double Curve - Delta Comp
Domain= FreeAir
Model= TSL
Revc= 5.600 Ohm
Fo= 257.397 Hz
Sd= 2.376m M²
Krm= 17.147u Ohm
Erm= 1.080
Kxm= 926.163u H
Exm= 0.771
Vas= 428.957m Ltr
Cms= 535.097u M/N
Mmd= 647.905m g
Mms= 714.500m g
BL= 2.985 T·M
Qms= 2.962
Qes= 0.726
Qts= 0.583
No= 0.974 %
SPLo= 91.905 dB
* End

[jkrutke]

Vas= 428.957m Ltr

Can I assume that means milliliters? .4 liters sounds just about what I would expect. What volume did you used for the rear cup when you did delta compliance?

Thanks for the help!

[KSA]

Yes, that's milliliters. I used 244 milliliters for the rear cup. I had to use an unopened driver to estimate the volume, since I don't have the open one at home.

[jkrutke]

I've finished testing the RS52 and the results are shown here:

http://www.zaphaudio.com/smalltest/

Note that I grabbed everything smallish that I had in the house and dumped it in here for comparison. This will become the future dumping grounds for measurements of small drivers. I've tested some of these before, but the measurement technique was outdated. (minitest/, 4.5test/) The way I do measurements today is much better.

Consistency was good but not perfect between the domes, so here's measurements of sample 2.

Dayton-RS52-FR-sample2.gif
Dayton-RS52-IMP-sample2.gif
Dayton-RS52-CSD-sample2.gif
Dayton-RS52-HD-sample2.gif

I believe sample 1 was the better performer of the two, so that's what I posted. Note the difference in impedance curves - sample 2 is rounded over a bit. In my experience, that usually means there is going to be a bit higher distortion somewhere. Something mechanical is preventing the driver from having a clean and symmetrical resonance. In this case it was between 1 and 2kHz. Still, even sample 2 measures excellently, so no worries.

Sorry, you guys will have to wait for Mark K's report for the comparison to a the Morel 2" dome. I didn't have one on hand, though I did have a Hi-Vi. The HiVi did not measure quite as well but was still decent considerin it's low cost. In fact all 6 drivers tested are good in some way, there's no stinkers in this group. (yet)

John

[Jim Holtz]

I've finished testing the RS52 and the results are shown here:

http://www.zaphaudio.com/smalltest/

Note that I grabbed everything smallish that I had in the house and dumped it in here for comparison. This will become the future dumping grounds for measurements of small drivers. I've tested some of these before, but the measurement technique was outdated. (minitest/, 4.5test/) The way I do measurements today is much better.

Consistency was good but not perfect between the domes, so here's measurements of sample 2.

Dayton-RS52-FR-sample2.gif
Dayton-RS52-IMP-sample2.gif
Dayton-RS52-CSD-sample2.gif
Dayton-RS52-HD-sample2.gif

I believe sample 1 was the better performer of the two, so that's what I posted. Note the difference in impedance curves - sample 2 is rounded over a bit. In my experience, that usually means there is going to be a bit higher distortion somewhere. Something mechanical is preventing the driver from having a clean and symmetrical resonance. In this case it was between 1 and 2kHz. Still, even sample 2 measures excellently, so no worries.

Sorry, you guys will have to wait for Mark K's report for the comparison to a the Morel 2" dome. I didn't have one on hand, though I did have a Hi-Vi. The HiVi did not measure quite as well but was still decent considerin it's low cost. In fact all 6 drivers tested are good in some way, there's no stinkers in this group. (yet)

John

Great work as usual John. The distortion seems to be even lower than the front runners in your 5.5" tests. Am I reading the graphs correctly?

Thanks for your hard work and contributions to the hobby!

Jim

[dwk]

good work John - this stuff is a great resource for a lot of people.

Nice set of tests, and a nice set of drivers. The RS52 may come off as the pick of the litter, but not by much.

[tktran]

Hi Mark,

I thought you were on holiday, and MIA. I stumbled across your results of your 12" subwoofer shootout promised earlier this year.

How come it's not linked off your website? Can I let the cat out of the bag, or post links to it on the forums?

[edit- typos]

[jkrutke]

Great work as usual John. The distortion seems to be even lower than the front runners in your 5.5" tests. Am I reading the graphs correctly?

Yup, you are reading the graphs correctly. The exact same testing method and level from the 5.5" test was used and a direct comparison is ok. The distortion is in the same league as the Scan Speak and Peerless Exclusive drivers. (the rest of the RS line is not in the same league however) This dome really compliments the Dayton RS woofer line, because distortion in the 1-3kHz range is not their strong point. I see a lot of 3-ways popping up with this in the future...

I think the real issue with this driver is how low it can cross over. I ran some power handling sims using KSA's T/S numbers, and if you want it to handle a full 100 watts, it's going to need an 800 or 900 hz crossover point. The Hi-Vi will likely run into the same issues. When I get some more time, I'll model a high pass filter in SE and re-run the power handling sims with the filter in place.

I don't have a whole lot of experience with dome mids, but I have to wonder if most of them share this "good distortion, low power handling" tendency.

[Mark K]

Hi Mark,

I thought you were was MIA. I stumbled across your results of your 12" subwoofer shootup promised earlier this year.

How come it's not linked off your website? Can I let the cat out of the bag, or post links to it on the forums?

No. Actually I meant to take it down. I still don't consider my setup quite up to the task for testing subwoofers. The data may be accurate, but I'm just not sure about it. For now, you can keep it to yourself, mumble it under your breath, etc, but it's not really to be made public.

Mark

PS "What link... :B "

[Jim Holtz]

Yup, you are reading the graphs correctly. The exact same testing method and level from the 5.5" test was used and a direct comparison is ok. The distortion is in the same league as the Scan Speak and Peerless Exclusive drivers. (the rest of the RS line is not in the same league however) This dome really compliments the Dayton RS woofer line, because distortion in the 1-3kHz range is not their strong point. I see a lot of 3-ways popping up with this in the future...

I think the real issue with this driver is how low it can cross over. I ran some power handling sims using KSA's T/S numbers, and if you want it to handle a full 100 watts, it's going to need an 800 or 900 hz crossover point. The Hi-Vi will likely run into the same issues. When I get some more time, I'll model a high pass filter in SE and re-run the power handling sims with the filter in place.

I don't have a whole lot of experience with dome mids, but I have to wonder if most of them share this "good distortion, low power handling" tendency.

John,

Thanks for the feedback. I'm becoming more comfortable translating the distortion tests you do but wanted to verify I was reading it correctly. It'll be very interesting to see how the RS52 matches up to the MDM-55. The MDM-55 does have a bit more xmax at 1.0 compared to .75 for the RS52. That's per Morel anyway. I don't know if anyone has verified it. I'm looking forward to seeing how the RS52 and MDM-55 compare in Marks tests.

The biggest issue with the RS52 is the huge faceplate which limits the tweeter choices. The new small faceplate Seas domes or a ribbon would work well. I'm looking forward to seeing the designs roll out using this driver.

Thanks again for the hard work!

Jim

[tktran]

Ok Mark.

Looking forward to any future measurements that you have in store for us. Keep up the great work.

PS. Did you ever do a design with the 18W/8535 following your 7" shootout?

[dlr]

Been out of town all week, will be next week

Here's a quick request for one of you guys that has your RS52's cut open. (DLR, fsmidt) Any chance of getting T/S parameters for this dome? This can probably be done delta compliance with the back off. Get the free air impedance curve, measure the cup's volume, (with liquid maybe?) put the cup back on and get the delta impedance. The reason this might be usefull is to do some excursion modeling.

The ones I tested aren't mine to cut open, and even if they were, I couldn't bring myself to mutilate them.

Excursion modeling will help select a crossover point. I've completed testing the RS52, and I can say that distortion is low enough through the low end that in most cases the dome will run out of Xmax before distortion becomes a problem. This dome seems like a big version of a 27TBFCG - no distortion down low, and how low you cross just depends on how loud you play it.

I've got another dome to test before I post the results. The RS52's are now on their way to Mark K.

Hi John,

Sorry I could't respond earlier. I had only short access to a PC while out of town. I'll be out the coming week as well.

Looks like you already have some of the info that you requested. I've been playing with SoundEasy and the RS52, but I'm still slow at getting good results from the DE/DF (still too reliant on CALSOD for optimization), so I may go back to playing with raw drivers this weekend. If I get more data on the RS52, I'll try to post it before the end of the weekend.

Thanks for those distortion results.

[dwk]

John,
The biggest issue with the RS52 is the huge faceplate which limits the tweeter choices. The new small faceplate Seas domes or a ribbon would work well. I'm looking forward to seeing the designs roll out using this driver.
Jim

With the faceplate off and going from the actual driver dimensions, you can get a 3" c-t-c spacing to the dayton ND-20. Assuming 1140ft/sec this gives about 4.5k as the upper limit, with 4k probably being more workable. With the factplate on and unmodified, you're looking at 3.5", which may work for a 3-3.5k xover, but of course the ND-20 is getting pushed a bit at that point. The XT25SC50 might be a good pairing, but I'm not sure of the dimensions.
I'm also interested to see how folks end up using it. 2xRS180 or 225 + RS52+ND-20 is a good place to start, but there are so many options.

[Rudy Jakubin]

Mark has just finished testing a pair of my RS52's;

http://206.13.113.199/ncdiyaudio/mark/blog.htm

Looks good to go.
My project incorporates 4 - DA175's for the woofers and the Dayton Neo tweet (ND20) in a 40" tall 10" wide box.
Starts in July. (in earnest).. Got's to hear these puppies sing!
L8'er

[AJINFLA]

Didn't want to start a whole new thread for buyout drivers, so I figured I'd tack it on this one .
If you are balking at the high ($33) price of the Dayton 2" dome, here you go http://www.madisound.com/cgi-bin/ind...10900&pid=2155 a whopping $26. Good amount in stock also. A bunch of other Titanium drivers too, if that tickles your fancy.
The tweeters with large rear chambers look interesting. Kinda. Sorta.
Specs forthcoming.

cheers,

AJ

[jkrutke]

Those MB quarts do look nice. Anyone have any experience with them? It's not like I need more speakers laying around, but stuff like that is hard to resist.

[yousuredo2]

someone Kind enough to point out some DIY units built with thease Mb's in 'em
Or think that they will pair well with a dayton rs180, and if so, care to design a crossover for MB 1" titanium tweeter, MB 2" Titanium midrange with a dayton Rs 180

[ThomasW]

Anyone have any experience with them?

I'm sure Jon has Clio files for both. We used them extensively in designs a decade or so ago...

[alexnick]

OK, I finished my exams, passed them very well, now I'm back to DIY!

As you know I want to build a pair of home speakers close to the M8ta, but still undecided due to the apparition of the RS52 and overboosed tweeter!
(I'm not convinced that I could modify the M8ta xover in order to suit to a smaller and narrower box and the TDFC would be at its limits with a smaller baffle.)
So aren't you guys preparing a 3-way version with the RS52?
Do you think that it would be possible to build a good ribbon to allow crossing under 1khz?(for the 2way M8ta) If not the 3-way M8ta would be the last solution!

[WillyD]

I believe that Jon is (at some point) going to design a 3-way center using the RS52, to compliment the Natalie Ps.