The 4Pi is a nice design, but there are better waveguides available now. Plus I would go active crossover as well. If you thought the 2226/DE250 combo were good with the old waveguide I think you'd be blown away by a newer waveguide (SEOS-12 or the B52 mentioned earlier). If 2226s are as plentiful around you as you say this might be a good experiment for you. BTW - since you are using subs a, 2206 or 2262 (both 12") might be a good choice too.
All that said, you might be among the cohort that just prefers direct radiators (no horn/waveguide). They do sound different. Unlike a waveguide that controls the directivity of the high end, they light up the whole room. This is normally bad, but you are using this in a room where you can control the character of the reflective surfaces. So the importance of controlled directivity might not be significant for you.
All that said, you might be among the cohort that just prefers direct radiators (no horn/waveguide). They do sound different. Unlike a waveguide that controls the directivity of the high end, they light up the whole room. This is normally bad, but you are using this in a room where you can control the character of the reflective surfaces. So the importance of controlled directivity might not be significant for you.
DIY Sound Group offers a SEOS-15/DNA-360 with two paralleled 8” woofers beneath it in the 88-Special kit. I preferred that to the SEOS-12/DNA-360 12” kit (Fusion 12). You could place the 88-Special atop their Maximus 15 midbass module.
Alternatively, you could go the Tannoy-esque route with the Vortex 12 or 15 coaxial kits they also offer.
Alternatively, you could go the Tannoy-esque route with the Vortex 12 or 15 coaxial kits they also offer.
Do you use an LR 4 (or even higher order) crossover between 1 and 1.5 kHz on that B&C/Eminence combo ?
Regards
Charles
Regards
Charles
These were the crossovers, they were built by Matt Grant. IIRC they are the same as the ones used in the Tempest, described as "The very linear response of each component allowed for an in-phase fourth order acoustic crossover at 1.3khz"
No. The pictured crossover is from a design done by forum member Bwaslo at a period of time when Bwaslo still lived near DIY Sound Group HQ and was helping forum member Scaper (erich @ DIYSG) develop a build for the then-new SEOS-12 waveguide. The Denovo DNA-360 compression driver later used in the Fusion-12 “Tempest” (designed by Jeff Bagby - RIP) did not exist yet. The Tempest (NLA) is a separate design using different drivers.
Well, I just got a minidsp usb mic and installed REW. The response on the 6ND430 looks just like the 18sound specs. A straight constantly rising response to 5Khz. My throw together crossover was actually very good but had a small peak at 1K. I spent about 4 hours reworking the crossover to smooth out the peak but like the sound better with the original build.
Anyway, if sensitivity is the goal I wouldn't use these below 400hz. At 100hz they're maybe 90db.
Anyway, if sensitivity is the goal I wouldn't use these below 400hz. At 100hz they're maybe 90db.
The crossover was built by Matt Grant. He built two pairs for me, one resides in a closed box with the Eminence 12" and DE250 in SEOS 12 (still with me, but replaced with the Tannoy DC12i), and the other is the pair you see pictured - it remains unused and is also still with me. I cannot recall whose design it was, Matt never claimed it to be his design, he just built them for me... Not sure of the 'Tempest' reference...
The Tannoy's and the custom built speakers with the above crossovers were similar in overall response and character - they imaged great a few feet behind my listening position, but imaging is not stable closer to the speakers.
This is only to be expected... IIRC Wayne Parham says that constant directivity speakers are not recommended unless the listener is seated behind the apex of the listening vortex and the speaker is toed it substantially...
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I take you at your word that Matt Grant assembled them, however, the pictured crossovers have a sticker on them indicating a design by Bill Waslo (forum member bwaslo). As I have explained, Bill designed at least one crossover using the SEOS-12 (as pictured). The Fusion-12 “Tempest” was designed by Jeff Bagby using different drivers.
It was in reference to your own words:
I was part of the initial crowdfunding of the SEOS-12 and have been following DIYSG since it was founded, I have followed the product evolution fairly closely.
And yes, an inability to sufficiently toe-in constant directivity speakers would render them pointless in any such scenario IMO.
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In the mail dated 15th June 2015, Matt conveyed that the 'Tempest' crossovers were ready, and those were the same crossovers he had already built for me once before, which reside in my currently unused SEOS/Eminence box. I had intended to build another pair with the new crossovers, but that project got shelved, so they are still with me...
Yes, that thought has been growing on me. I hoped that I could work around it, but to be honest, I'm losing this fight.
I've been trying for years to find a design that can put out the SPL and frequency response of a serious studio "main" monitor such as the Genelec 1234A, without breaking the bank. 3-5K US$ is is my budget, but these things cost up to 10X that figure.
The only affordable and relatively simple to execute options I have found are all horn loaded CD based ones (Econowave, Pi, SEOS etc.), but they all seem to have this toe in requirement, which makes them completely unsuitable for studios conforming to ITU recommendations...
The 'monkey coffin' thing going on these days is interesting, maybe I'll spend some more time looking in there... but those don't look like they can take the type of abuse that studio monitors are often subjected to...
A constant directivity pair of speakers setup as shown in figure 1 of the itu recommendation you mention should sound great. A big part of the motivation, at least as I understand it, behind the toe in is to avoid early reflection is off the side walls, which the 30° toe in would likely accomplish.
It’s possible “tempest” was a working name that got carried over from Bill’s initial design to the Fusion-12 build (designed by Jeff Bagby) that we have discussed. That would be the only explanation for this degree of confusion.
So a couple things.......
SPL.........you’re an engineer yes?.........why the high SPL goal? 100db occasional transient peaks and that’s pushing it..... your ears are already shutting down to protect themselves......within 20 minutes, you won’t be able to trust them
The Genelec is your ideal.....a great speaker.....with not a compression driver in site....not unlike nearly all of the professional mix/mastering studios around the world.....try an apply parallel compression to vocals while mixing and i’ll play you a master with no dynamics on 99% of the world’s listening devices.....which are NOT horn loaded compression drivers
If this project is an exercise in self indulgence, which it sounds like it is.....don’t worry about standards and just build what you have envisioned......but of this is a system for serious commercial work, we need to start over from the beginning because the design thoughts here are waaaaay off the rails.
SPL.........you’re an engineer yes?.........why the high SPL goal? 100db occasional transient peaks and that’s pushing it..... your ears are already shutting down to protect themselves......within 20 minutes, you won’t be able to trust them
The Genelec is your ideal.....a great speaker.....with not a compression driver in site....not unlike nearly all of the professional mix/mastering studios around the world.....try an apply parallel compression to vocals while mixing and i’ll play you a master with no dynamics on 99% of the world’s listening devices.....which are NOT horn loaded compression drivers
If this project is an exercise in self indulgence, which it sounds like it is.....don’t worry about standards and just build what you have envisioned......but of this is a system for serious commercial work, we need to start over from the beginning because the design thoughts here are waaaaay off the rails.
Genelec uses compression drivers with constant directivity waveguides on some of their main monitors including the s360a and their "flagship" 1236a. I think the seos12 and a 10inch woofer should be quite similar to the s360a
The 1236 is a listening party and production monitor.......big difference.....and the S360 is a ghost and rightly so......near impossible to critically mix or master with.
85 dB continuous with a headroom of 20 dB (so 105 dB peaks) is what monitors are calibrated to in film mix stages. If I am to meet this goal @ 4m, I will need peaks of 117 dB @ 1m. Typically though, I build smaller rooms... most of my rooms are calibrated between 79 and 82 dB + 20 dB headroom. Which is still peaks of up to 114 dB @ 1m.
I quote Philip Newell quoting Gilbert Briggs - "loudspeakers are somewhat like boxers... In general, a good big one will always beat a good little one."
Have you been to a film mix stage when a high impact sequence is being worked on...? It gets super loud! Most engineers who work on high SPL sequences take regular breaks. Those that don't eventually suffer from hearing disabilities, like many rock musicians.
I have "designed", with my superficial knowledge, systems that are being put to use to do serious commercial work, everyday. If you consume a lot of Indian entertainment, you have probably heard some of it.
True dat. It is a very sophisticated design, what with that complex MF/HF waveguide and all... If I could afford it, I would buy it. If I thought that it was within my scope to put together something like it, I would have headed in that direction.
If seems to me that if you want serious SPL without too complicated a design, CDs/waveguides are the way to go. It would take a super seriously engineered soft dome mid-range/tweeter system to accomplish the SPLs that a CD/waveguide can, with ease. JBL M2s, Augspurgers etc. have chosen to go down the CD/Waveguide route, and they are being used in some pretty serious installations...
On a related note, I cannot understand how the soft dome tweeter in the Quested Q412D manages to put out 130 dB peaks, without a waveguide. Likewise, with the 3" dome mid-range. BTW, did you see the price on that?? 😀
An externally hosted image should be here but it was not working when we last tested it.
To put things in context - I am not looking for an "audiophile" quality, super refined system. Most likely, the speakers will be driven by inexpensive Class D amps through an inexpensive processor/manager such as the MiniDSP... I'm looking for something loud and clear, with as much finesse as I can accomplish on a budget. In all cases, these monitors will be complemented with a pair of super refined nearfields such as the the Genelec 8331 SAM, my current favourite small monitor...
I've wondered similar things, this is just a guess, but I think they are referring to pink noise with 130db peaks, which would put most of the power in the bass drivers. I'd be curious to see if anyone here knows for sure though.
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1.5 inch tweeter
crossover frequency 4500 hz
For 130 db you would need 0.4mm xmax from that tweeter