Peerless 830874: a pair on the way.

[Pete Schumacher]

I went ahead and ordered a couple of the PPB cone 6.5" woofers. A LONG time ago I built a couple of vented enclosures to house the venerable Dynaudio D21AF tweeter and the excellent Peerless 850439 CSX cone midwoofers. Those woofers wound up in a pair of towers that now sit to either side of my mom's flat screen (see Peerless 3-way in my signature).

So I've got a couple of enclosures that are cut for these two drivers already, and I'm anxious to re-use them and make a Christmas present for my daughter. I checked the D21AF today and they really test exceptionally well, even after all these years. I bought them in 1989! Distortion levels are hovering around the .2% range but the usable range is no lower than about 2500Hz. Natural response starts rolling off around 3000, but even with them rolling off, distortion didn't approach 1% until below 1000Hz. Very impressive for a 21mm tweeter. Based on the plots for the Peerless, this pairing should work out just fine.

They'll get a new finish and should clean up very nicely. Stay tuned. This should go together pretty quickly.

[rpb]

You'll like the 874. Sounds very much like the nomex version to me. You can cross it anywhere, and it sounds good. I've crossed at 4k, and liked the sound a lot. (Add an LCR if you want to cross that high.) The off axis is lumpy that way, but the speaker is very coherent crossed that high. I've also crossed as low as 1.7k, and several points in between. I think the x-over I liked the most used a 3.4 mH coil, and a cap on the woofer. The coil was a 3.6mH that I took some turns off of it, so 3.4mH is a guess. All my filters were full, BSC. Morel DMS30 tweeter, and at times a Morel mdt28 that's older than your tweets. I know you don't need my help, but I have several filters for the woofer if you get really pushed for time.

[Pete Schumacher]

You'll like the 874. Sounds very much like the nomex version to me. You can cross it anywhere, and it sounds good. I've crossed at 4k, and liked the sound a lot. (Add an LCR if you want to cross that high.) The off axis is lumpy that way, but the speaker is very coherent crossed that high. I've also crossed as low as 1.7k, and several points in between. I think the x-over I liked the most used a 3.4 mH coil, and a cap on the woofer. The coil was a 3.6mH that I took some turns off of it, so 3.4mH is a guess. All my filters were full, BSC. Morel DMS30 tweeter, and at times a Morel mdt28 that's older than your tweets. I know you don't need my help, but I have several filters for the woofer if you get really pushed for time.

Thanks for the information! I'll get measurements in this enclosure and find the sweet spot for the tweeter. When Dynaudio made these, the intention was to use 1st order crossovers. After looking at the impedance plot, there's really no way you could do it without at least some kind of compensator for the impedance peak around 1500Hz. But I'll do my best to keep the tweeter circuit as simple as possible. And most likely your value of ~3.5mH for the woofer is what I anticipate for this design as well. I'm sure there will be additional shaping required.

Below is the response of the tweeter, unsmoothed, from about 6" away. That distortion is exemplary! And because I'll have plenty of padding on the tweeter, I'll likely push it to a 2500Hz XO point.

I've got two more of those tweeters too.

[lasse]

I tend to use Dynaudio tweeter in all designs...

Regards// Lasse

[Pete Schumacher]

I tend to use Dynaudio tweeter in all designs...

Regards// Lasse

Can't get them here anymore . . . they are nice though.

You should try the Transducer Labs tweeters sometime. Amazing!

[lasse]

Can't get them here anymore . . . they are nice though.

You should try the Transducer Labs tweeters sometime. Amazing!

Hi, thanks for the advice.

No, Dynaudio drivers can only be obtained on ”EBay” and other used-stuff-places nowadays.

Regards// Lasse

[PWR RYD]

I have a pair of D28/2 Dynaudio tweeters I bought from Madisound back around 92. They measure and sound fantastic. I'd like to repurpose them again in something really special.

[rpb]

Thanks for the information! I'll get measurements in this enclosure and find the sweet spot for the tweeter. When Dynaudio made these, the intention was to use 1st order crossovers. After looking at the impedance plot, there's really no way you could do it without at least some kind of compensator for the impedance peak around 1500Hz. But I'll do my best to keep the tweeter circuit as simple as possible. And most likely your value of ~3.5mH for the woofer is what I anticipate for this design as well. I'm sure there will be additional shaping required.

Below is the response of the tweeter, unsmoothed, from about 6" away. That distortion is exemplary! And because I'll have plenty of padding on the tweeter, I'll likely push it to a 2500Hz XO point.

I've got two more of those tweeters too.

[ATTACH=CONFIG]n1353898[/ATTACH]

First order might be possible. My sims don't tend to match actual x-over values, but sometimes they are in the ballpark, and can be made to work with some trial and error. I've not tried a first order, but after making this sim this morning, I think I might take a shot at it, and see if I like it.

[rpb]

Pete, you should make a design with a currently available tweeter, if any fit the box prep. Lots of people could get great sound cheap if they buy now. Most will pass on the sale because there are no established designs. I could do the same, and might eventually, but some of these potential builders would not trust my design to sound good enough, because I don't make the rounds to the DIY events. Budget decisions always effect these potential builders too. Like my sim shows a 6mH coil. That LCR can be eliminated, but I would want it in my speaker. A bc25sc04 tweeter might work nice with this 874. Probably not quite as nice as our older high end tweeters, but it might be closer than I think.

[Pete Schumacher]

1st order requires acoustic alignment. So this will definitely be LR4 slopes.
No other tweeter will fit this enclosure, but I do have those very inexpensive Peerless aluminum domes on hand that are currently in the Ares build using the 6" Anarchy woofers. Those tweeters could easily be used with the 874 and deliver great sound for very little money. I may try and construct an enclosure to pair them up.

[Whitneyville1]

Pete and rpb, something like a 3.5mH on the woofer would match up closely with the "Veepers" using the 830875's. Lots of nice Perrless/Vifa tweeters to chose from, hint, hint.

[Kornbread]

1st order requires acoustic alignment. So this will definitely be LR4 slopes.
No other tweeter will fit this enclosure, but I do have those very inexpensive Peerless aluminum domes on hand that are currently in the Ares build using the 6" Anarchy woofers. Those tweeters could easily be used with the 874 and deliver great sound for very little money. I may try and construct an enclosure to pair them up.

Have a pair of those tweeters on the shelf. Anxious to use them. Question; see that small piece of plastic attached to the screen that looks like a round H? Is that there for protection during shipping, or what? At first I thought it was a piece of tape to protect them during shipping, but now I'm not sure.

[Pete Schumacher]

Have a pair of those tweeters on the shelf. Anxious to use them. Question; see that small piece of plastic attached to the screen that looks like a round H? Is that there for protection during shipping, or what? At first I thought it was a piece of tape to protect them during shipping, but now I'm not sure.

That is the phase shield. The RS28A has something similar on it too. Metal dome tweeters operate as a piston to much higher frequency than do silk domes, and as you go up in frequency, the wavefront from the middle of the dome will begin to cancel the wavefront from the edges of the dome. Having that small area be opaque to the sound wave from the middle of the dome extends the response of the tweeter and reduces the effect of the cancellation.

[Pete Schumacher]

Pete and rpb, something like a 3.5mH on the woofer would match up closely with the "Veepers" using the 830875's. Lots of nice Perrless/Vifa tweeters to chose from, hint, hint.

At $35 each, it would make sense to get a bunch on order and do a build like the 3-way in my signature. Those three woofer towers are really excellent sounding speakers with a nice footprint. Too bad that aluminum dome is out of stock until February. I really like how it performs. Tough to beat at that price.

[rpb]

Ani_101 is going to build a 3-way tmwwww with the 874 as mid and woofers. The tweeter will be a Morel CAT378 horn loaded soft dome. The woofers will be in their own box, so the tm portion may change.