Just looking at the initial part of the thread, its the original Lab15, which has considerably different specs, so is there a 4 ohm variant I missed?
GM
For HIFI only, one normally wants a fairly low Qtc cab alignment, so with this already relatively high Qts driver that will rise considerably at high power peaks, you’re looking at anywhere from a ~7.5 [same as the BR] – 30 ft^3 sealed alignment with peak power rolling off at 12 dB/octave below the BR’s ~60 Hz/120 dB/m, ergo is ~18 dB down at the BR’s –20 dB and only outperforms it below ~20 Hz.
Doubling the number of speakers, cab net Vb and power adds +6 dB.
From a purely technical POV then, a high passed BR seems the obvious choice overall. That, or if considerably less peak SPL is acceptable over the sub’s entire BW, then the drivers can be put in much smaller sealed cabs and EQ’d using a L-R transform, which turns a very under-damped [‘ringing’] alignment into the desired lower Qtc, wider BW one.
GM
GM,
First of all, thank you. Secondly, your knowledge level so far exceeds my rudimentary level that I want to make sure I am "getting it".
I believe the recommendation is that a ported enclosure of 7.5 ft^3 (net) tuned for 27 Hz is a good target; is that correct?
I am not sure what your thoughts might be on this same driver (4 ohm version) in the Dag Johansen (40 Hz) enclosure suggested earlier in this thread.
I wold appreciate your comments.
Beau
First of all, thank you. Secondly, your knowledge level so far exceeds my rudimentary level that I want to make sure I am "getting it".
I believe the recommendation is that a ported enclosure of 7.5 ft^3 (net) tuned for 27 Hz is a good target; is that correct?
I am not sure what your thoughts might be on this same driver (4 ohm version) in the Dag Johansen (40 Hz) enclosure suggested earlier in this thread.
I wold appreciate your comments.
Beau
You’re welcome!
Correct, for ‘m0reilly’ as I understand his needs till told different; otherwise, it depends………
on your band-width [BW] and peak SPL requirements
on your room’s acoustics
where you prefer to locate the subs
peak power available
Absent any of this knowledge, then yes, the 7.5 ft^3 alignment is as good an alignment to start with as any since you can tune it a bit lower by making the vent longer [don’t recommend making it any shorter] and/or damp the vent to roll off its bass some if it sounds ‘boomy’ or even seal it up if that doesn’t work well enough.
Depending on the other missing info though, a larger cab may ideally be required.
I’ve no thoughts beyond what I posted earlier:
“Just looking at the initial part of the thread, its the original Lab15, which has considerably different specs, so is there a 4 ohm variant I missed?”
IOW, it theoretically shouldn't work well enough to gamble the time/$$ on it unless someone else has some experience with it, which I don’t, and not willing to read through such a long thread to see what insight, if any, might be available.
Anyway, Dag is the person to ask.
GM
looking at that post, i don't know what you were trying to show. sorry. so the box is smaller than what winisd shows, or...? i don't need to plum the depths, so to speak, but a larger bass voice to match my simple maggie setup. after hearing that maggies in general are power hogs and not aggressive... i would have to disagree in my situation. i don't want 'loud', i want 'big'. i guess i'll try that big box ported option.
I attached the Hornresp design for you/whoever to download to HR’s IMPORT file and open it in HR to view the design and if you don’t like it, then use the Loudspeaker Wizard to ‘slide’ your way to an alignment that you think will work better for you.
I don’t use WinISD, though I do use the Pro version since it’s more full featured and is more accurate in some ways.
Anyway, Its default reflex alignment is an extended bass alignment rather than the T/S max flat alignment most freeware programs use as a default and basically what I simmed in HR. As such, it calculates a larger cab tuned lower, which in turn reduces its peak power handling capability, but is a higher sound quality [SQ] alignment as reflexes go, so to the first approximation it’s the preferred one for your app.
If a steep 100-110 Hz XO is acceptable, then bjorno’s TTQWT would be better still.
That said, what do you mean by ‘big’?
GM
big...as in presence, a swift 'compression' of air, or a bass that is felt more than a rubbery 'boom'. maybe i picked the wrong driver for this...i had my heart set on a set of seas 'roys', but again, i'm trying to do things on the cheap...hopefully the wife won't mind a couple of refrigerator sized cabs...
Ahh that's what I get for not reading. I just popped in and saw the thread and that came to mind.
Did Dag ever post a hornresp file that accurately predicted the as built cabinet response? If so someone can easily see if this new spec'ed 4 ohm lab 15 would work well in there....or just grab a driver and a few sheets of wood and see what happens! $200ish invested for a test cabinet isn't terrible.
If you don't mind, can you provide the dimensions you are planning in building to? Outside box dimensions will be fine.
![URL]](https://www.diyaudio.com/forums/[URL=http://imageshack.com/f/exFgWoLij][IMGDEAD]http://imagizer.imageshack.us/v2/150x100q90/537/FgWoLi.jpg[/IMGDEAD][/URL])
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.