The JPG - A tribute to my dad's DIY work

[wogg]

Nice design. Thanks for sharing. I bet the BR version could really belt out the deep bass! You mentioned that the mid and tweeter were vertically oriented. How was this accomplished? Did the originals use custom, angled mounting rings of some type?

Thanks! The originals had some fantastic bass, classic sealed feel to it where it wasn't overdone or in your face, but super deep when called for. I have to admit I'm not sure what you mean by BR though. Also, the "vertically oriented" is probably the wrong term, I just meant vertically aligned. Just like this design, the mid and tweeter were in a line with the cabinet on the side. Nothing fancy.

SB just released a new 2.5” mid to their Satoti line. Looks pretty robust but of course it’s pricey. May be worth look though as I think it will be the mid that will make or break this design. It’s available in Wisconsin Sent from my iPhone using Tapatalk

I see the ScanSpeak Discovery D7608/9200-10 on said "other" place. That looks nice! That would do the trick a little better, but without comparably measured FRD and ZMA files I can't theorize. If one were to build and had proper measurement gear to design using real life files, I'd go with that one. It ups the cost by about $120, but would probably be worth it.

[Wolf]

Bass-Reflex = BR.

Wolf

[wogg]

Bass-Reflex = BR. Wolf

Ha! I was overthinking that one.

[jtheisen521]

I was referring to the Satori MD60N-6 dome mid. But they’re pretty steep at $168 Sent from my iPhone using Tapatalk

[johnnyrichards]

That Satori won't play very low at all, and the impedance curve implies they skipped a shorting ring.

[wogg]

This should be a straight forward physics exercise. A certain diameter driver producing a certain SPL at a certain frequency will require a particular Xmax. I found this calculator online: http://www.baudline.com/erik/bass/xmaxer.html
So some quick numbers in there should help tell us what the limit is at 500Hz for these mids.

• Using 2" for the dayton, I get an output of 100dB at 1 meter before breaching the 1mm Xmax, which is shy of the woofer capability. That mid will stress out when the music gets loud.
• That Satiori is worse, with only 0.5mm of Xmax to play with. The extra 1/2" isn't enough to compensate for the lack of Xmax, so it's likely to poop out at 97dB.
• The ScanSpeak D7608 looks the best, with a 3" diameter and 1.5mm of Xmax it should push near 110dB before giving up. The downside is that it needs a rear chamber, but a simple stuffed PVC cap should do it fine. The loss of volume will be insignificant for that big cabinet and woofer.

So my conclusion is:
The design as published above will work fine, but expect low mid-range distortion increases when cranked to party levels.
To correct that, pony out some $ and go for the ScanSpeak Discovery D7608/9200-10. You'll need to be capable of measurements to adjust the crossover to use the alternate mid, but it will crank with low distortion much better.

[a4eaudio]

wogg - would you be interested in simulating your design with the new GRS 15PT-8 and trying to get the woofer-to-mid crossover in the 800's? (I have no idea if that is possible.) It looks like it models well in 5.8 cf, is a little more sensitive, and can handle 150-200 watts before hitting xmax. If you don't have time or just aren't interested I won't be offended

[DeZZar]

Depends if you modelled for BSC as loss or gain (appears to be loss from your sim). The 15" will of course experience somewhere around -6db for the majority of the range your expecting from it so by the time you compensate you're at ~85 - maybe a little higher if you depend on positive room contributions. The mid/tweeter will play at their respective rated outputs in their range - so my point is you likely don't need a high sensitivity dome midrange in this setup which opens up the possibility of ~3 inch cone drivers that wont suffer from the same distortion concerns inherent in pushing the limits of a dome.

Perhaps something like the very smooth SB10PGC21-4 (3") will meet up with the 15" much easier and sits right at that 85db point.

You mentioned the originals ran with a paper mid - so just something to consider.

Cool design though - my nephew has been asking for a design like this as a nod to yester-year!

[wogg]

wogg - would you be interested in simulating your design with the new GRS 15PT-8 and trying to get the woofer-to-mid crossover in the 800's? (I have no idea if that is possible.) It looks like it models well in 5.8 cf, is a little more sensitive, and can handle 150-200 watts before hitting xmax. If you don't have time or just aren't interested I won't be offended

That will require a little graph tracing, but I may be able to pull that off. No promises based on my life / time availability ;)

[a4eaudio]

Understood, no hurry.

[DeZZar]

That will require a little graph tracing...

Here you go...

[wogg]

Thanks! That makes things quicker, now it's just a trip through the response modeler and into the sim.