12 inch car sub in B&W 801 cabinets?

[audiomagnate]

I bought 2 beat up pairs of old B&W 801 series 80s and combined the good parts from both to build a beautiful pair of functioning 801s, which I love. I now have an extra empty pair of 801 bass cabinets that I would like to use for subwoofer cabinets. These are sealed and around 4 cubic feet each. The local Craigs is LOADED with cheap 12 inch car subs from Sony (xplode) Infinity, JL and the like, but they all seem to want tiny 1.2 cu ft cabinets. I know excusion will go up in an oversized cabinet and power handling will go down, but I just want to extend the bass of my 801s and protect the expensive original 801 woofers from damage by rolling them off at 60 Hz or so. Original 801 woofers are NLA. I just want deep, clean low bass down into the low 20s. I have the power, Nak PA-7AII and the electronic crossover, I just need some woofers to go in the box.

[OscarS]

they all "seem" to want 1.2 ft³ boxes because that is what the mfg recommends in this day and age of smaller and smaller cars. The fact of the matter is, a lot of car subs have a high Qts that could use a large box in order to control the Qtc.

Look for a sub with a ~ 0.60 for Qts, low 20s Fs, and ~ 2 ft³ Vas.

[DeonC]

May I suggest a pair of Rythmik Audio SW-12-04 Servo Sub Woofer drivers. At first you can buy the drivers, and later on the servo amps. If the XO frequency is going to be higher than 120Hz, I would suggest AE Speakers TD12S drivers.

Deon

[audiomagnate]

Originally Posted by DeonC

May I suggest a pair of Rythmik Audio SW-12-04 Servo Sub Woofer drivers. At first you can buy the drivers, and later on the servo amps. If the XO frequency is going to be higher than 120Hz, I would suggest AE Speakers TD12S drivers.

Deon

I have a Velodyne ULD-15 already and want to stay away from servos. But thanks anyway. I also have a few big pro amps on hand, Cerwyn Vega A400s, that I want to use for power. Thanks for the suggestion anyway. Suggestions for appropriate popular 12 inch car woofers would be appreciated. Getting technical info, even model numbers, from car audio folks on Craigs can be difficult.

Thanks OscarS, that's just the info I was looking for!

[audiomagnate]

It looks like I can get a pair of Infinity Reference 1250W (Yes, the power handling IS the model number) for about $100/pair, new in box. Fs = 25.4, Vas = 3^ft (84 liters), Qts = .47, Xmax = 11.5 mm. Close enough?

Until I can find a reasonably priced Behringer DSX2496, I will be using either a 50 or 90 Hz 12 dB/8ve crossover. I have no subsonic filter. My main speakers are either the 801s or Infinity RS 2.5. Both have expensive, delicate woofers not suitable for HT. I usually go with the 50Hz crossover when listening to music and raise it to 90 when watching Blu-rays. For now my crossover is a Gemini CX-1000, which sounds amazingly good for what I paid for it.

I recently sold a VMPS Larger, and miss the heck out of it. If I can get close to the sound of the single VMPS with two of these, I would be very happy.

[sreten]

Hi,

Those drivers will be fine in 4 cuft each, but boy, does adding
a vent tuned to 18Hz improve the low bass end or what ?
Very big differences in the 20Hz to 40Hz octave,
in the bass extension and the maximum SPL.

rgds, sreten.

[audiomagnate]

Originally Posted by sreten

Hi,

Those drivers will be fine in 4 cuft each, but boy, does adding
a vent tuned to 18Hz improve the low bass end or what ?
Very big differences in the 20Hz to 40Hz octave,
in the bass extension and the maximum SPL.

rgds, sreten.

I have downloaded WinISD Pro and will be adding this driver. How do I upload my added data?

Anyway, these cabinets are so beautiful, I hate the idea of cutting a big hole in them. But I'll play around with ported designs it in the program and maybe do one at a time and compare the two. Thanks for all your help so far. I can't wait to get some decent bass back into my system.

[sreten]

Hi,

Put on some big feet and mount the port in the bottom ?

rgds, sreten.

In winISDpro you have to define your own new driver.
Autocalculate helps with missing data required.

I thought the 801 cabinets took a 15" driver, not 12" ....

[audiomagnate]

Originally Posted by sreten

Hi,

Put on some big feet and mount the port in the bottom ?

rgds, sreten.

In winISDpro you have to define your own new driver.
Autocalculate helps with missing data required.

I thought the 801 cabinets took a 15" driver, not 12" ....

No, 801s use 12 inch bextrines. I have entered enough data, and it looks like sealed vs. vented means down 11 dB at 20 Hz vs down 5 dB vented. That is rather huge. It looks like I'll be doing some cutting. It doesn't seem to matter much which vented system I use i.e. 3dB shelf, Quasi Butterworth etc. A 4 inch port 24 inches long is what it calls for, more or less.

[DeonC]

Originally Posted by audiomagnate

I have a Velodyne ULD-15 already and want to stay away from servos.

Sorry for the OT, but could you tell me more about your experiences with servo subs?

Thanks,
Deon