better for my requirements? good midbass, not necessarely LF extension, as much weight as possible in the midrange.
Hi Murphy,
While I crunched some simple vented box numbers, I saw that Scott already has such a box on Madisound's page for this driver. I was doing 10 and 14 liters, but since his is an existing design (and more volume is better), I used his ~16 liters.
His 50mm vent is close enough to PVC 2" pipe's inner dimensions. So just to give you an idea of what's possible by changing vent length:
Green: 55hz (~8.3cm vent length)
Yellow: 65Hz (~4.9cm vent length)
Pink: 70Hz (~3.72cm vent length)
Gray: Just for the contrast of what's possible, a quick pass at an EBS (but you're using subs so irrelevant).
So if you're still looking for in-room tuning flexibility, my advice would be to build Scott's box, adjust vent length (and damping) to suit, and then if it's still too bright overall, consider a circuit (or other options for changing the response at the listening position, e.g., toe-in).
I wish you good luck, and report back what you eventually find.
While I crunched some simple vented box numbers, I saw that Scott already has such a box on Madisound's page for this driver. I was doing 10 and 14 liters, but since his is an existing design (and more volume is better), I used his ~16 liters.
His 50mm vent is close enough to PVC 2" pipe's inner dimensions. So just to give you an idea of what's possible by changing vent length:
Green: 55hz (~8.3cm vent length)
Yellow: 65Hz (~4.9cm vent length)
Pink: 70Hz (~3.72cm vent length)
Gray: Just for the contrast of what's possible, a quick pass at an EBS (but you're using subs so irrelevant).
So if you're still looking for in-room tuning flexibility, my advice would be to build Scott's box, adjust vent length (and damping) to suit, and then if it's still too bright overall, consider a circuit (or other options for changing the response at the listening position, e.g., toe-in).
I wish you good luck, and report back what you eventually find.
Attachments
P.S. Red: 75Hz (2.77 vent length).
If you can digital EQ, then it would be best to go with Green, and cut whatever you need. It's free, it's flexible and putting a bump in a vented box's response is nobody's first choice (i.e., using a Q higher than .707).
Also, if you have 8-foot ceilings, you may find that you tickle the floor-ceiling ~70Hz room mode (which can be annoying) so in that case, the 70Hz tuning might arguably be the worst possible choice, but you can find out in room.
Last thought -- all this merely shows what's possible changing vent length. Be careful with the volume when doing so. The boxes I'd -personally- choose would be Green (if using subs) and Gray (if no subs), with a circuit if needed.
If you can digital EQ, then it would be best to go with Green, and cut whatever you need. It's free, it's flexible and putting a bump in a vented box's response is nobody's first choice (i.e., using a Q higher than .707).
Also, if you have 8-foot ceilings, you may find that you tickle the floor-ceiling ~70Hz room mode (which can be annoying) so in that case, the 70Hz tuning might arguably be the worst possible choice, but you can find out in room.
Last thought -- all this merely shows what's possible changing vent length. Be careful with the volume when doing so. The boxes I'd -personally- choose would be Green (if using subs) and Gray (if no subs), with a circuit if needed.
hi
just to be sure, your talking to do those box:
http://www.madisound.com/pdf/SmallReflexA122p-191012.pdf
Do the MarKen.
Onken style enclosures are a bit special - thanks to the high-resistance "slot" ports, they have none of the characteristics I associate with other bass-reflex enclosures (muddled midbass, boomy/peaky response, port noise - all are completely absent)
Even if you're crossing fairly high, I'd still want to start with a good foundation, and the MarKen will give you a very nice, polite, smooth, and extended response with which to work.
Onken style enclosures are a bit special - thanks to the high-resistance "slot" ports, they have none of the characteristics I associate with other bass-reflex enclosures (muddled midbass, boomy/peaky response, port noise - all are completely absent)
Even if you're crossing fairly high, I'd still want to start with a good foundation, and the MarKen will give you a very nice, polite, smooth, and extended response with which to work.
Sure. You just have to watch the vent length, when modeling with multiple vents.
jeff
My boxes aren't officially Onkens. I don't know of any program that sims them directly... i have to extrapolate from the sims.
dave
And just to point out, the Onken per se was a specific variation on the old Jensen Ultraflex, which itself can trace its lineage back to Thuras's original reflex box. Their alignment is almost diametrically opposed to Dave's boxes, which only look like them. In the Onken and its predecessors, the object was to use the massive vent system to provide maximum efficiency at Fb. Dave is using the friction inherent to the lengthy high aspect ratio vents to provide a quasi-aperiodic response.
Very well said Scott. I'm going to steal that
dave
handy to have a trained historian around - but does he take out the trash?
Quite right - my post should have read "Fonken style boxes", but my fingers got ahead of my brain...
To be clear, my specific experience is with the CHR-70's in Dave's dCHR-Ken70 (which is very similar to the dMarKen7, if that helps clear things up at all) - the stand-mounted bookshelf-sized cabinets in this post: http://www.diyaudio.com/forums/full-range/176673-chr-ken.html#post2354861
I built it, I like it. It has such competent bass that I don't even feel it needs a helper woofer - obviously a woofer would help power handling at higher volumes, but for office listening they sound great full-range.
Other enclosures may well be equally good, but I'd shy away from simplistic designs with a bit of pipe for a port....there's a reason Dave's designs are as they are, and that's simply that they work really well!
Hi peoples,
1. If "boom" means resonating, vented cabs are inherently prone to boom but some simple tricks can take the boom out as long as the design is sane.
2. The vent length approach can tune a certain part of the response. But if the main concern is avoiding boominess, that's a whole different priority. You can have both, but boom can be hard to tame since it's a function of the room as much (or more) than of the cab.
3. Find your room's modes, using a room calculator or whatever works. That's what you'll be fighting in terms of boominess (overhang).
4. If you want to experiment with a resistive vent, just make any existing vent resistive using any number of tricks. Stuffing a vent with straws is cheap, easy and effective within its limits. If you love that approach, definitely go for the Fonken-style boxes (although making a vent in wood is a move away from adjustability, but could be worth it, and the box may have other benefits yet to be heard).
1. If "boom" means resonating, vented cabs are inherently prone to boom but some simple tricks can take the boom out as long as the design is sane.
2. The vent length approach can tune a certain part of the response. But if the main concern is avoiding boominess, that's a whole different priority. You can have both, but boom can be hard to tame since it's a function of the room as much (or more) than of the cab.
3. Find your room's modes, using a room calculator or whatever works. That's what you'll be fighting in terms of boominess (overhang).
4. If you want to experiment with a resistive vent, just make any existing vent resistive using any number of tricks. Stuffing a vent with straws is cheap, easy and effective within its limits. If you love that approach, definitely go for the Fonken-style boxes (although making a vent in wood is a move away from adjustability, but could be worth it, and the box may have other benefits yet to be heard).
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