The Q is, in short, the shape of the roll-off of the box with driver. The end Q of the box is (almost) always higher than the Q of the driver in free air. The spec for the driver is 0.89 so that is as low as you can get -- that would take an infinite size box (in practise you can get real close in a lot smaller box than that).
A box with Q = 0.707 is max flat, 0.5 is considered as low as you want to go, 1.0 as high as you really want. Anything higher than 0.707 starts to put a bump at the low end before it rolls off, not all that bad a thing with a driver like this that doesn't go very low anyway).
As you can see from the attached sim, not a lot of difference between 4 and 50 litre, and i added a sim for 2 litre which is not horrendous. You can see where the biggest box possible comment comes from. Keep in mind damping will increase the apparent box size (say max 20% in practice).
dave
Attachments
Here's a slightly more expensive option. This is per pair and these guys are in Australia. These drivers are very well regarded.
How much better they are than the other drivers listed here I'm not sure but I imagine quite a bit, especially bass, maybe planet10 can confirm this?
Mark Audio CHR-70 Mk II - Metal - PAIR
How much better they are than the other drivers listed here I'm not sure but I imagine quite a bit, especially bass, maybe planet10 can confirm this?
Mark Audio CHR-70 Mk II - Metal - PAIR
As I noted earlier, it's more than likely at least 1.07, plus combined with a +/- 20 Hz Fs variance, this driver ideally needs either an OB or TL.
GM
I don't ever pay attention to those as they are sometimes wrong, so didn't notice they are the preliminary specs listed on the Aussie site.
I DL the manufacturer specs listed under MANUALS/RESOURCES off to the R.H. side of the page: https://www.parts-express.com/pedocs/specs/297-2156--hibm65c20f-8-data-sheet.pdf
GM
I DL the manufacturer specs listed under MANUALS/RESOURCES off to the R.H. side of the page: https://www.parts-express.com/pedocs/specs/297-2156--hibm65c20f-8-data-sheet.pdf
GM
Get a calibrated USB mic as you don't have to deal with your sound card calibration. The UMIK-1 from miniDSP or UMM-6 from Parts Express are both good. Download REW software and you are set. That is fantastic software and fully featured for free.
xrk971
I think it sounds great, it is completely balanced and isolated from any other object so it produces a unique sound that I really like. I thought it would struggle to produce any bass, but it holds its own just fine.
ewollowe
I am not the first person to make a dodecahedron, they are traditionally used as a omnidirectional point source for acoustics analysis. I have seen a few other about on the internet including a 3D printed version and one cast from concrete.
I think it sounds great, it is completely balanced and isolated from any other object so it produces a unique sound that I really like. I thought it would struggle to produce any bass, but it holds its own just fine.
ewollowe
I am not the first person to make a dodecahedron, they are traditionally used as a omnidirectional point source for acoustics analysis. I have seen a few other about on the internet including a 3D printed version and one cast from concrete.
3D printing seems like an obvious solution to irregular shapes like this, but cast concrete - that'd be a very interesting jig
oh, I see it now, casting for each face, then glued up
oh, I see it now, casting for each face, then glued up
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
- Status
- Not open for further replies.