Ideas for a kick-ass 8" monitor

Tweeter:




Vifa XT25 ring radiator. Looks like great extension on the top-end and it can be crossed reasonably low. Not nearly as pricy as the ScanSpeak ring radiators.

http://www.parts-express.com/tymphany-xt25bg60-04-1-shielded-dual-ring-radiator-tweeter--264-1012



HiVi M8N 8" woofer. Have had good experience with their stuff in the past. Accord to PE simulation I could get vented F3 of 29Hz which is believable.

http://www.parts-express.com/hivi-m8n-8-aluminum-magnesium-woofer--297-446

• This will be a much bigger cabinet more suitable to stand-mounting in a larger room. I expect bass extension to be better
• Considering a front-mounted port(s)
• Still brainstorming, considering other drive units, feel free to chime in

 

Have you considered a coaxial driver instead of a tweeter? Going from tweeter to an 8" seems like either driver would have to cover a frequency they aren't comfortable with.

 

Good point, but I'm wary of coaxial drivers. In the system I've outlined in my mind, a 2k 2nd order crossover will make the cut. Need to do simulation of course.

If I could find a coaxial driver that could be tuned as low I might be swayed.

 

Considering this tweeter now that I'm reading up:

https://www.madisoundspeakerstore.c...b-acoustics-sb29rdc-c000-4-ring-dome-tweeter/



Similar ring radiator design with really smooth response and low Fs. Bit more expensive, but lower distortion than the XT25 according to Zaph. Might very well make a difference because I'm going to be crossing relatively low

 

Do you think I could get comparable bass extension and slam with Dayton RS225? I kinda want these things to be bass cannons. If I'm going to do the ported sound I want get every last Hz out of it.

Not touching either of those tweeters though. Ring radiator for me. I'm curious about them. If I can get HD800-esque clarity and extension out of them then I won't have think about other technologies and I'll save up for the TOTL Scanspeaks.

 

Asking for full range in a 2 way seems problematic in a small enclosure. It's also asking ALOT of the woofer, most 8"s will start to beam pretty hard by 1500hz, which is a pretty low crossover for most of those tweets. If space isn't a huge issue, I'd almost think a waveguide and CD would better if you want good bass extension and a reasonable crossover point between woofer and tweeter. Of course the sensitivity mismatch and need for CD correction in the high end will make designing the x-over a bit less simple. That or perhaps sticking with 5-6" woofer that won't beam as much and looking at a building a sub to handle the lowest octaves.

 

It won't be a small enclosure. We're looking at stand-mount...50-60L volume. If the M8N (even the RS225 gets close to it according to sim) specs aren't complete BS then F3 will be in the low 30's.

The 8" to 1" hand-off is tough no question. I think I can get the M8N to work with a bit of impedance correction. Worse comes to worse I do plan on having an outboard crossover which gives me the flexibility of bypassing in favor of digital slopes and surgical EQ on each independent driver.

I already have an excellent 5" midwoofer and pretty good dome matched with a decent subwoofer. This project has different goals in mind.

 

http://www.madisoundspeakerstore.com/approx-10-woofers/seas-prestige-a26re4-h1411-10-paper-cone/

Not an 8" but given your acceptable cabinet size this could actually work pretty well with a 1" tweeter, 60 liters sealed should get you near 30hz with cabin gain, but it should be very comfortable crossing high and keep it's polars in an acceptable range.

 

With 60L enclosure why not go 3-way?

http://www.troelsgravesen.dk/ScanSpeak-3W-Discovery.htm

 

I like 2-ways. I do plan on building a similar cabinet...with screw-in baffle panels that mark the bracing points.

 

M'yeah - 8+1 is very hard to integrate properly, tricky crossovers and a rather narrow choice of drivers. A large 60L enclosure would make plenty of space for a nice small mid (maybe even dome) woofer. I also like 2-ways, but mostly in 6+1 configs. Otherwise I'd risk putting a crossover point right in the critical midrange.

In your case - try looking into horn tweeters, maybe you'd get something that goes low enough.

 

Horns/waveguides could certainly mate lower then most 1" tweets. The SEOS-15 is fairly cheap, could fit well in a 50-60L cab, along with a larger woofer could, I think do it all better then trying to integrate an 8.

Strong and controlled down to 1000hz.

Measurements http://attitube.com/loudspeakers/beta-the-white-noise-seos15-constant-directivity-horn-adventures/

http://www.diysoundgroup.com/plastic-seos-12/seos-15-cd.html

 

I'll need to remember those Denovo waveguides/compression drivers when I put my OB's back together. They might be very competitive with Hawthorne AMTs.

Pretty much set on SB acoustics tweeter at this point. Still need to settle on appropriate woofer.

RS225 has better bandwidth and higher breakup can be more easily cured with typical slopes + impedance compensation. M8N boasts notably better bass extension according to sim, but that's with given specs, which, as Merv said, might be BS. RS225 is almost double price though. If this were a commercial project that might deter me as that would mean cost get's passed on to customer at rate of 5x or more. But since this is a one off dealio an extra $50 is chump change. Makes me glad I'm not side-grading between 4-5 figure boutique loudspeaker designs.

Since this project will be ongoing and modular, the more expensive "superior" woofers can always be rolled in later. Even port tubes will be rollable, although cabinet dimensions will be fixed more or less. Fortunately for drivers of the same size, cabinet volume isn't drastically different.

 

http://www.diyaudio.com/forums/full-range/273524-10f-8424-rs225-8-fast-ref-monitor.html

Lots of measurements of the RS225 in a two way monitor.

 

That guy looks to be getting good extension out of the RS225 and he's using a smaller cabinet than I'm thinking. 4-ohm version and EBS cabinet should also give me an edge on output. Inherent bass quality of woofer remains to be seen...

Curious TL design on that mid though. Sometimes I forget how well extended those 3-5" mids can be

 

Pardon me, how could this little speaker which uses 4x 6.5" woofers down to 20Hz when the SPL is less than 87dB?

http://www.whatsbestforum.com/showthread.php?18437-Kii-Three-speaker-review-english-version/page3

What happened?

 

OJ did you ever build these?

 

Yeah, OJ! Stop hiding the goods!