I agree with weltersys, plug the ports. Those 4648A's are Pro Audio concert subs and not home theater subs. I can't believe they have a 40ish hertz tune when an 88 key piano plays to 27.5 hertz. You CANNOT boost a BR enclosure below its tuning frequency. The drivers WILL unload...no control...over excursion. Once you plug the ports, then you can boost the 20 hertz frequency. You are working with ALOT of cone area that most people on diyaudio.com can't relate to in a home setting. Go over to avsforum.com where multiple sealed 24" subs is the new standard in tactile response.
You will very likely damage them from over excursion. What are you driving these with?
Mine actually get to 30Hz in room easily with no EQ and the standard 40Hz tuning. Then i have a 25Hz HPF on them.
Circles cut out with a router jig slightly larger than the ports, use a 1/4 round after cutting the circles.
Or you could just buy wooden disks, sand the corners smooth before painting:
Worth not making so much sawdust..
I've also used poly foam with handles made from tape. The foam can be easily be cut with a bread knife.
Gorilla tape (comes in white, 2" or 3") looks better than the duct tape used on this guitar cabinet:
You could then easily pull one or both plugs for different tunings- I changed frequently from sealed for guitar, two open for Theramin, or one for bass.
That said, unless you're planning a 1970s disco party, you'll probably leave the cabinets sealed
From what I've read, the Sonics 800x appears to be bridged mono - 800 watts at 4 ohms.
How many of them do you have?
Art
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I have two of the Sonics and one Yamaha P3500.
I have four other JBL cabinets that I plan to stack in the front of the room as double bass towers ro go with my line array speakers (ran in parallel to 4 ohms). I plan to power those with the Sonics. One amplifier per.
I plan to use the Yamaha P3500 bridged with the set of four behind the couch (wired series parallel to 8 ohms). Right now I'm using the Sonics as they weren't in use yet.
I have four other JBL cabinets that I plan to stack in the front of the room as double bass towers ro go with my line array speakers (ran in parallel to 4 ohms). I plan to power those with the Sonics. One amplifier per.
I plan to use the Yamaha P3500 bridged with the set of four behind the couch (wired series parallel to 8 ohms). Right now I'm using the Sonics as they weren't in use yet.
Check out some of the enclosure tests on data-bass.com. They plug ports with measurements.
I have some drivers in this setup that are significantly quieter than the others and am trying to figure out why.
I'm trying to figure out if I wired this wrong or if a some drivers are dead.
It's supposed to be series parallel to 8 ohms and I'm getting 4.6 ohms..
I measures 8 separate drivers that came from the speakers I'm still prepping to paint. Those are measuring 10 ohms instead of 16.
Attached is my wiring diagram.
I'm trying to figure out if I wired this wrong or if a some drivers are dead.
It's supposed to be series parallel to 8 ohms and I'm getting 4.6 ohms..
I measures 8 separate drivers that came from the speakers I'm still prepping to paint. Those are measuring 10 ohms instead of 16.
Attached is my wiring diagram.
Attachments
The DCR (dc resistance) of the nominally 16 ohm JBL 2226J is 10 ohms, so they are reading exactly correct.
The series parallel DC resistance should be 5 ohms, you have ~.4 ohms wire resistance in the measurement.
I'd suggest thicker wire if you want the very best damping factor, but not a big deal in the grand scheme.
The 3.4 ohm (quieter) cabinet may have one or both drivers with partially shorted coils.
Probably hear them dragging if you push on the cone, or run a sine wave sweep.
I'd suggest heating the vinyl stickers (a heat gun or hair dryer may be enough, or a torch) and scraping them off with a putty knife.
Sanding them with around 100 grit make the paint stick (not great, but enough for sitting around), but you'll still see the outline of the sticker.
Art
A 0.1 ohm difference in the DCR of drivers is well within the usual manufacturing tolerance, don't worry about matching them.
Also, check if your ohm meter actually reads "0" ohms when you short it's leads, or touch them to a terminal screw..
An "8 ohm" 2226H has a 5 ohm DCR (could possibly be a wrong recone kit or replacement), but should be louder, not quieter than the "16 ohm" 10ohm DCR 2226J driver, so the 4.8 ohm driver is probably "bad".
Take a listen to it.
If it is bad, you could put a cover plate over its hole, the single good driver will still get the same power as the rest.