MiniByzy (Mini Byzantium) Build Thread

[Pete Schumacher]

Re: MiniByzy (Mini Byzantium) Build Thread

I'm fairly certain that the driver ErinH tested had QC issues. I went through several drivers being returned to PE due to wildly differing TS paramters until I finally landed on two which were very close to each other and published specs. The interesting thing is that visually inspecting the two "good ones" with the others is that the glue lines were much cleaner and that at rest the suspension/cone looked to rest further out that the others and I measured approximately 2.5mm of this by the amount of voice coil exposed above the neo slug. If the defective drivers are assembled ~2.5mm in then the asymetry ErinH measured is not surprising...

Wow, that's almost exactly the problem he found, that same offset.

The 4 sets we have all look great, and have very clean delivery all the way up to full excursion. Very low distortion as well.

I've been messing around with a new crossover after getting to hear them with the RS28A. That waveguide seems to be a perfect match for these two particular domes. Here's what I measured recently. This is in room, raw with 1/12th octave smoothing, roughly 10W input (loud!), 0 and 45 degrees. It looks like the target of consistent off-axis performance is being met quite nicely.

Over the weekend, we'll be trying out the Transducer Lab N26C ceramic in the waveguide to see how it works.

[CUtiger]

Re: MiniByzy (Mini Byzantium) Build Thread

Related to the great klippel data provided by Erin H, I requested additional information about this line of drivers, and specifically the NE225's.

I'm fairly certain that the driver ErinH tested had QC issues. I went through several drivers being returned to PE due to wildly differing TS paramters until I finally landed on two which were very close to each other and published specs. The interesting thing is that visually inspecting the two "good ones" with the others is that the glue lines were much cleaner and that at rest the suspension/cone looked to rest further out that the others and I measured approximately 2.5mm of this by the amount of voice coil exposed above the neo slug. If the defective drivers are assembled ~2.5mm in then the asymetry ErinH measured is not surprising...

[D, Rose]

Re: MiniByzy (Mini Byzantium) Build Thread

Hey olu, I'd love to make a set of speakers just for YOU!!!:D

[olu78]

Re: MiniByzy (Mini Byzantium) Build Thread

Great work Pete! I wish I was available to enjoy the Chi-town diy event, unfortunately, I was confined to the Dominican Republic. SO SAD!! Related to the great klippel data provided by Erin H, I requested additional information about this line of drivers, and specifically the NE225's. These drivers, along with other scanspeak units were designed by one of the danish transducer design teams. By design, there was asymetry built into the units, assumptively, to meet certain performance goals, of which, I am not privy to. As we know, tymphany/vifa/dst/scanspeak was in the process of reorganization, and these driver designs were transferred, and ultimately brought to market as peerless platinum transducers. The decision was made to standardize/streamline the brand offerings. When such changes occur, it can be difficult to retroactively confer with 'original engineering,' to ascertain a sense of clarity and understanding, as it relates to design choices. Having seen klippel data of scanspeak revelator drivers, the 18w's exhibit a bit of motor/damper asymetry. Considering and respecting the superior brain-talent accessible to the company, I have no doubt that, had they wished to, they could have eliminated most if not all asymetry(see 12wu/15wu/18wu). This leads me to speculate this was 'by-design.' I also learned that, at a recent ALMA event, the topic of using klippel in transducer design was agreed by all as a great tool. However, the problems/limitations of klippel interpretation by the enthusiast public was discussed, as it is very often the case, we do not readily have access to transducer designers, who can explain engineering trade-offs and choices. There is a direct correlation between these considerations and supplier capabilities, lead-times, cost and price-point, manufacturing consistency, and demands imposed by marketing, to name a few. For any videophiles, a great example would be the Pioneer Elite 101FD, signature series plasma hdtv's. Many enthusiast question why the best hdtv's of today have yet to completely outperform these sets, manufactured in 2008. The elite's were quite a bit more expensive than competitors offerings. The difficulty of manufacturing these sets, on a large scale, contributed to the price premium. Today we have wonderful, high performance displays, but choices and compromises with any product, play a large role. Another relevant concern, is the fact that the same design teams for top-of-the-line drivers, may be responsible for developing drivers to meet lower price-points, and complete entire product lines. This being the case, it is important to ensure that a less expensive driver not encroach upon performance benchmarks established for flagship products. Imagine if the discovery line of drivers outperformed the illuminator woofers. This cannibalism would eliminate the utility and reason for purchasing the higher priced drivers. Years before Dumax, or Klippel equipment were available, there were wonderful sounding drivers in the marketplace. I would love to see how these performed and measured, relative to today's best. Likely, you would have drivers that measured well, yet left much to desired audibly, and the opposite. If the opinions of the Mini Byzy are to be believed, despite the measured asymetry, it is very possible to engineer great sounding designs. Let us not toss the baby with the bathwater, but rather, use all of the tools at our disposal, when considering drive-unit decisions, and designs. Thanks to all, who enable us to do so.

[jcpahman77]

Re: MiniByzy (Mini Byzantium) Build Thread

Now that's a cool idea. Ed was trying to think of a grill for the woofer opening that used magnets to hold on to those bolts. But simply sticking a small piece of felt on both sides (to make it easy to remove), you are making grills for the bolt holes.

I'm still trying to get Ed to think about mounting the baffle to the enclosure with bolts from inside grabbing threaded inserts on the back of the outer baffle. We'd have to make an access panel in the bottom, but who cares about bolt holes there? It would require a somewhat "blind" assembly, reaching and feeling for the bolt and hole in the baffle, but would be pretty simple really. The end result would be a baffle without any visible means of removal to get at the drivers inside. Perfectly clean . . .

I like it. And thanks for making me think about it jcpahman77.

I'm just glad I can think that I was given OCD for a reason Pete.

[Pete Schumacher]

Re: MiniByzy (Mini Byzantium) Build Thread

While I personally don't mind the screws Wonder if you could just affix a a little circle of felt to something like the below?

http://www.parts-express.com/pe/show...number=320-010

Now that's a cool idea. Ed was trying to think of a grill for the woofer opening that used magnets to hold on to those bolts. But simply sticking a small piece of felt on both sides (to make it easy to remove), you are making grills for the bolt holes.

I'm still trying to get Ed to think about mounting the baffle to the enclosure with bolts from inside grabbing threaded inserts on the back of the outer baffle. We'd have to make an access panel in the bottom, but who cares about bolt holes there? It would require a somewhat "blind" assembly, reaching and feeling for the bolt and hole in the baffle, but would be pretty simple really. The end result would be a baffle without any visible means of removal to get at the drivers inside. Perfectly clean . . .

I like it. And thanks for making me think about it jcpahman77.

[jcpahman77]

Re: MiniByzy (Mini Byzantium) Build Thread

I hope my comment hasn't been taken out of proportion. The exposed screws in no way would sway my interest in buying a set of the Mini ByZy's, or whatever they go by now. I just saw it as being below the quality of the rest of the build and felt it was worth mention; and it seems to have worked, if D, Rose has an idea now I'm sure it'll be as impressive as the rest of the cabinet work.

[CUtiger]

Re: MiniByzy (Mini Byzantium) Build Thread

While I personally don't mind the screws Wonder if you could just affix a a little circle of felt to something like the below?

http://www.parts-express.com/pe/show...number=320-010

[jcpahman77]

Re: MiniByzy (Mini Byzantium) Build Thread

I just figured if there wasn't something available a person with your talent could come up with something. It was the only 'weak link' I saw in the cabinet design. The level of craftsmanship is astounding.

[D, Rose]

Re: MiniByzy (Mini Byzantium) Build Thread

Hey, jcpahman,... as for those big 'ole baffle anchoring bolts in the baffles, a friend just pointed out some caps designed to snap in to hide them. I haven't seen these caps yet, but they might be just a perfect option for my new "Commercial" (:rolleyes:Darth Vader mechanical breathing inserted here:rolleyes venture with Vapor. Thanks for watching these cabs develop with me, and it was a fun and challenging build!:D

[dlneubec]

Re: MiniByzy (Mini Byzantium) Build Thread

Excellent, Pete. However, as much as I typically prefer a hardwood look, its tough to top Ed's painted version!

[Pete Schumacher]

Re: MiniByzy (Mini Byzantium) Build Thread

Beautiful, Pete. A nice looking speaker should sound about 10% better than an ugly one. In this case you might be approaching the theoretical limit of 25%. :D

It looks like the outer perimeter of the waveguide is slightly truncated at the bottom (adjoins the woofer cutout) and also upper right and upper left (cab edge), or is it just the photos? Even if it is, maybe it does not matter because you are into the outer portion that matches the baffle to the waveguide proper, and because any truncation is so slight?

John

Thanks! I'm sure Ed will be quite pleased to read your assessment of his cabinetry and his painter's finish.

You're very observant about the waveguide being truncated. It's at the very outer edges, leaving at least 90% of the waveguide still operating to control the tweeter directivity. From the measurements we got, it is only slightly changed from the full waveguide on a 2'x4' baffle. And baffle diffraction effects are hugely reduced if not eliminated in the tweeter passband. That diffraction control, and the totally dead cabinet made by Ed, may have helped with what some observed as a rather large sound stage. Ryan (---k---) experiencing a feeling of actually being in a hall. When you can do that with point source monitors, you're doing something right. The OB guys say that's their proprietary territory . . . . :p

Since the above baffle was fashioned by Ed, we made a couple modifications to his waveguide milling jig resulting in an even more uniform guide than what you see pictured above. The baffles that showed up in Chicago were "almost" perfect, but having been painted white, were a little more forgiving of showing off what few imperfections were left. There just wasn't time to take care of the last 2% of the finish. Ed's getting that done this week.

I hope he can start making a few baffles for the gang soon. It doesn't take much extra elbow grease to take his milled MDF and make a very nice WG baffle.

[jcpahman77]

Re: MiniByzy (Mini Byzantium) Build Thread

Beautiful, Pete. A nice looking speaker should sound about 10% better than an ugly one. In this case you might be approaching the theoretical limit of 25%. :D
John

Like putting that Flowmaster sticker on my car gives me 5 more horsepower? lol

[OlderMongrel]

Re: MiniByzy (Mini Byzantium) Build Thread

Finally! We got the veneered cabinets done. Looking good too.

As Ed said in a recent email . . . It was a good build.

I'll post response plots soon for the current XO and RS28F implementation. I still want to evaluate the RS28A, because it really sounded nice in Chicago.

What's up next? Maybe a two-way using Ed's waveguide baffle and the RS225?

Beautiful, Pete. A nice looking speaker should sound about 10% better than an ugly one. In this case you might be approaching the theoretical limit of 25%. :D

It looks like the outer perimeter of the waveguide is slightly truncated at the bottom (adjoins the woofer cutout) and also upper right and upper left (cab edge), or is it just the photos? Even if it is, maybe it does not matter because you are into the outer portion that matches the baffle to the waveguide proper, and because any truncation is so slight?

John

[REM.Audio]

Re: MiniByzy (Mini Byzantium) Build Thread

After appreciating them in person,10 of 10 is a fair assessment,Imho.