Anyone looking for Peerless HDS 2-way design?

[Jay_WJ]

I know some people are interested in building a 2-way with the Peerless HDS Exclusive 7" woofer and the HDS 1" tweeter.

I posted a 2-way design with these drivers at my website. I'm pretty confident that this design is ready to build with only minor fine-tuning to the builder's taste. I know that this is quite an exception as a design that is produced by in-box simulations with FRDC tools. But there are some reasons why I can say this, especially for these Peerless drivers. To see why, visit my website. Find the design in page "Preliminary Crossover Designs."

[Dave Bullet]

Nice work Jay,

I presume baffle diffraction was modeled on the Madisound pre-cut baffle for these drivers? Do you have impedance plots as well? One small tweak you could include is an impedance flattening circuit for tube amp users.

Cheers,
David.

[Jay_WJ]

No it was modeled on the vented cabinet design in my Dayton and Usher page (.75" horizontal and 5.75" vertical offset from the woofer's center on 8.5" wide baffle).

I actually built my Usher design also on a baffle where the tweeter is centered. I built this for center channel use. The effect of centering the tweeter was exactly what the BDS predicted: a bit stronger low end of the tweeter. So I decreased the primary capacitor value a little bit (by 0.68 uF), then the centered and offset versions became almost indistinguishable in their voicing.

Can we hear the effect of a .68 uF difference? Yes, I did. If you doubt, try for yourself. I bet you will.

I think using the Madisound precut baffle will have the same effect. That's why I recommended to tweak the primary capacitor value to find one that suits the builder's taste.

P.S. Impedance compensation network for tube amp use may not be so appropriate for 85 dB sensitive speakers. If I had wanted to try an MTM version of any of the designs I created, I would've added that option.

[DcibeL]

I'd love to see someone built your design Jay_WJ. I'm currently working on a design using the HDS 8" woofer and the HDS tweeter. It won't be ready for a while yet though, as I have some more pressing matter to attend to before I can work on this project some more.

I don't have any measurement tools available to me, so I'm designing completely using the FRC tools, and the knowledge I've gained from the Loudspeaker Design Cookbook. I am planning a large tower design, with bass response down to about 30Hz. I am a little worried about the maximum output I will get, especially after baffle step correction, since I am running out of excursion at about 30W (I think).

[Jay_WJ]

That excursion limit is typical for any two driver 2-way vented designs. The HDS 8" driver should hav much better power handling than most 5 to 7" drivers. With 30 watts they should play loud enough for music listening. For HT use, however, you may need to use a subwoofer with a crossover (usually in a receiver) if you like watching movies at a loud volume.

BTW, which FR data did you trace to model your design? I find that Zaph's measurement is pretty accurate and easy to trace. I just looked at the 830884's responses at Zaph's tidbits page. Very smooth FR and excellent distortion performance. I'd cross low with this woofer, though, due to the usual early start of beaming of an 8" driver. A 1.5 kHz XO should be possible with the 810921. I used it with a 1.55 kHz XO in my Usher 2-way to obtain a good result.

[DcibeL]

Yes, I wasn't complaining that the xmax of the driver was too small, just that since I am tuning the cabinet to such a low freq that I reach excursion quicker than I would like. I thought about using two woofers (in either an MTM or TMM configuration), but I don't think the added cost would be worth it, and it would add more complexity to the design.

I chose the driver (and tweeter for that matter) specifically because of Zaph's measurement, and I've used Peerless drivers in the past and have been very happy with them. This 8" driver has excellent distortion characteristics, and cone breakup is high enough that it can be used quite easily in a 2-way system, something not hat common in an 8" driver.

Oh, and yes, I did my traces from Zaph's measurements, though they're not far off from the manufacturer's measurements.

[Jay_WJ]

The 830884 will be very easy to work with. The 7" version needs a notch filter to obtain a flat response due to the mild rise in the 700 to 900 Hz range. But the FR of the 8" looks very smooth. A simple electrical 2nd or 3rd order filter will do. And I'd use as narrow a baffle as possible (e.g., 9" wide) to naturally compensate the dip at 800 to 900 Hz.

Compare the beaming of the 8" to that of the 7" or 5" in the manufacturer's data sheets. The 8"s off axis rolloff clearly starts earlier than smaller drivers. I'd put a crossover frequency between 1.4 kHz and 1.6 kHz. Will a 1.4 kHz XO point be too low? I don't think so. The 810921's low end distortion performance is excellent, and you don't have to worry about its power handling. As input power increases, the woofer will give up before the the tweeter does, anyway.