DIY New England

October 22, 2016

This year's DIY was different than others. There was a total of five of us this year. Two of those who drove brought speakers to show while I had several of mine to fill in the remaining time. This provided a lot of time for us to evaluate them and discuss details with the designer. Plus, we got to listen to a wider variety of music with each one. The reviews posted at the Parts Express Tech Talk Forum are included at the bottom of page.

First up was Mike A's 3-way. It comprises a Seas ER18RNX, Scanspeak 10F/8414 and Hiquphon OW1. That was the speakers. Perhaps the most interesting component is the DSP crossover. Mike is using the Raspberry Pi 3 (IIRC). This is coupled with a plain-Jane sound card that outputs to a six-channel amp board. The RPi is running a Linux kernel with third-party open source software that is controlled from Python code that he wrote. It's an amazingly small and inexpensive setup. As mentioned in the PE posts below, it sounded great, may need some fine tuning on driver integration, primarily the woofer section and could probably benefit from a higher quality sound card and amp, but will no doubt be quite a system when he's done with it. I hope that he brings it back next year.

MikeA 3-way RPi Setup

Next up was Jon's stand mounted 3-way. It comprises an Anarchy Exodus 4, Dayton RS-100 and SB 19mm. I was impressed with everything played. The Implementation of the crossover was excellent. The SB19 is a winner. My favorite tweeter is the OW1 which is 19mm as well. I think that I'd have to test the SB19 and OW1 in the same system to see if the OW1 is worth the extra cost over the SB19 at this point. He put up a build thread at the Parts Express forum.

Jonathon's 3-way Jonathon's 3-way

Last up was my dipole system. It comprises two 10" Peerless buyouts (Genelec) from Parts Express, ScanSpeak 15W4531G and Seas DXT. Teh crossover is handled by the Ultimate Equalizer Lite from Bodzio Software. I'm still using the UE5 version in a Windows 7 PC with a Delta 410 sound card. The card output goes to an MSB MVC-1 stepped attenuator. The power amp is an old Kenwood KM-X1, 100W/ch. Using the UE with it's test signal option I measured all six channels at 0db settings of both the UE and the MVC-1. The widest range of lowest to highest channels differed by 0.12db in gain at 1KHz. Needless to say I am exceedingly pleased with the setup.

This is the first DIY event that gave me the opportunity to show this system fully setup and working properly so that I could get some feedback. I still have some painting and finishing to do. The baffle and center support will be matched to the M/T baffle.

Dipole1
Dipole2

The M/T dipole section was replaced with some old M/T combos I've had for a long time. The first one was in an old 3-way I used several years. This one has a ScanSpeak 12M/4631 and Hiquphon OW1. It's one of my favorite combinations. That was followed by a test box I had never actually auditioned. It has as ScanSpeak 13M/8636 (Kevlar) and ScanSpeak D2905/9300. These were both set up in projects in the UE as well. Since I had the measurements already, it took about 5 minutes to set them up the night before. I never even listened to teh 13m/9300 combo before the DIY event. That's how easy it is to set up a project. The one caveat I would point out is that I treat the baffles significantly for diffraction so that the on-axis is smooth before filtering and off-axis rolloff is very smooth. I don't have to make a specialy effort to consider the power response because of this.

12M/OW1

These short "reviews" are taken from the thread at the Parts Express forum.

jclin4:

As Mike P mentioned, active systems were center of the day, as were three-ways. I was the throw back, bringing my horizontal monitors with passive XOs.

Mike A and Mike P brought a stand-mount 3-way with Hiq OW1 tweeter, small format mid (make which I did not capture), and SEAS ER18RNX woofers. A nice complement of drivers, and well put together in reasonably sized cabs. But the star of this setup is the active crossover implemented in python script and associated python and C libraries running on a raspberry pi 3. This was software they created on their own and not an off the shelf software package. Mike A was able to make adjustments to the crossover by changing parameters in his code on his macbook (I think the Rpi and Mac were using his phone as a wifi access point). The system, which is a work in progress, also included a Sure 6-channel amp board and USB sound card (not specifically designed for raspberry pi, but on a circuit board similar in size). As a WIP, it's probably not fair to evaluate for SQ, but what I heard sounded good and offers great promise, particularly as they refine the software and iterate on improving and optimizing components, like the power supply.

As mentioned, Dave demonstrated an interchangeable active system that was actually 3-systems-in-1. The base (or bass) of it all are dipole, H-frame woofers (15" I think?), two per side. The first tweeter+mid module on top were dipole mids (Revelator) + SEAS DXT tweeter. This combination sounded fantastic. Very open and dynamic, with great detail.

Next module had a smaller mid (Scanspeak, I think, about 3-4") in monopole configuration with Hiq OW1 tweeter. This sounded very different than the dipole module. The upper XO was LR2 and for kicks, Dave changed this to LR8 on his PC running Ultimate Equalizer software (try doing LR8 with a passive XO!), and we listened some more. Immediately the midrange became clearer and more well defined. Pretty much all there heard this.

Last module had Scanspeak tweeter (9300 or 9500) and a 4-5" fiberglass mid (apologies for not getting the exact driver models...these are in a higher-end space I generally do not play in), like the second module also in a sealed box. These sounded very neutral and balanced and I would be very happy listening to this configuration over the long-term, but then we then ended by putting the dipole module back in just to get one more listen. These were magic!

Michael P:

I liked your speakers a lot, they were solid all around (and I appreciate the cabinet design and finish... creative, but not *too* creative). The damped open back let the midrange "spread out" a bit, and we were able to position the speakers wide apart to get a big soundstage without it collapsing to the left/right. Pretty impressive considering there weren't any costly components in there. These, among a few other designs I've seen recently, have enlightened me about the virtues of small 3-ways (as long as you are brave enough to tackle the mid/woofer crossover). Now you just need to try an active crossover.

As far as Dave's speakers, they were quite an experience to listen to; all of the permutations were technically excellent, and we were able to make comparisons that explored the realm of perception and differing tastes. I was of two minds about the first TM module. I like the focus of the DXT tweeter, and it played clean and loud (preserving the bite on electric guitars, without bothering your ears). The sound from the dipole 15W[?] midrange was incredibly clean and spacious (another word that came to mind is "liquid"). In fact, Dave mentioned that he had matched the polar response of the tweeter to the front half of the polar response of the mid. So they were perfectly integrated tonally, but I felt a bit of a spatial disconnect between the monopole treble and dipole mid. I found the second module (12M/OW1) with monopole mids to be more comforting even though they were not as outwardly impressive. I preferred the LR8 version to the LR2 version, which sounded a bit subdued (or maybe compressed) in the midrange by comparison. And the third module (with the Kevlar mid) was interesting too. The highs didn't have the "Technicolor" detail of the OW1 and voices were very similar tonally, but perhaps slightly less clean. It was really interesting to listen to the (mostly subtle, sometimes mildly obvious) variations between speakers that all had quality drivers and a ruler flat frequency response.

I remember thinking the bass section (H-frame) was pretty strong, but that this is the way most larger speakers sounded in that room. It was a nice quality bass, much more even than what I can get in my room. (I guess in my room I have about the same broad balance, but all of the bass is around 40 Hz, so the upper bass is leaner.) We got those woofers moving (with, what was it, Pink Floyd?).

I liked the tone of Mike A's speakers, they sounded plain and neutral. He was just getting started on the crossover but I thought it was an improvement from the last time I listened at his place. It was also a big help to use the digital input and avoid going through an extra ADC. However, the bass made me scratch my head a bit, wondering if there was a phase issue. All the other speakers sounded richer to me, and I'm not sure why--maybe part of this was the quality of the DAC and amplifiers. We'll keep working on them, and post some more information about the Raspberry Pi crossover setup and build photos in the near future ... I guess he has to decide what they should be called first! (The midrange is a Scanspeak 10F/8414.)

One last dog picture. Faye (nearest), 14+ years old, Ruggles (walking), 10.5+ and Dandy (on dog futon in the distance), about 14. They are all rescues, so we have no exact ages.

dogs