JBL 4648 subwoofer - this is a monster (PRICE LOWERED) AND 4645B subwoofer

[pat_in_dfw]

This is from their cinema series but I've seen it used in pro sound as well - both touring and installations.  I had it in my home theater.  Back when I was single I could really rock out watching movies.  But now with kids I rarely have a chance to really get it breathing. I am going to be moving as well so I don't have room for it at the new house.

 

EDIT - I already moved and I've had these sitting in storage for over a year.  They need a home.

 

Local pickup in the Dallas area only.  There's no way I'm going to even try to ship this thing.  $400 OBO each cash only.

Low Frequency Drivers:	(2) 2226H
Frequency Range:	30 Hz - 1.8 kHz (-10 dB)
Power Capacity (Continuous Pink Noise):	1200 Watts
Power Capacity (Continuous Program):	2400 Watts
Sensitivity:	100 dB SPL (1W, 1m, 3.3ft.)
Crossover Frequency:	500 to 800 Hz recommended
Nominal Impedance:	4 Ohms
Dimensions (HxWxD):	991 x 648 x 451 mm (39 x 25 1/2 x 17 3/4 in)
Net Weight:	42.7 kg (94 lb)

 

The JBL 4648A low frequency system is designed for general reinforcement and motion picture theater use where high power output with smooth power response and low distortion are essential. The 4648A system covers the frequency range from 35 Hz to 500 or 800 Hz, depending upon application.

 

The 4648A 4 ohm system uses two 2226H 380 mm (15 in) patented Vented Gap Cooling TM transducers for high power handling and reduced power compression. The transducers feature 100 mm (4 in) voice coils operating in a large symmetrical field geometry (SFG) magnet structure to reduce a second harmonic distortion to inconsequential levels. The total linear excursion capability of each transducer is 10 mm (0.4 in), peak to peak, and total harmonic distortion (THD) is less than 2.5% from 40 to 800 Hz with sine wave input of 100 watts.

 

The enclosure is constructed of dense stock and is extensively braced on all panels. Net internal volume is 225 l (8 cu ft), and the enclosure is tuned to 40 Hz. Port area is large, ensuring minimum turbulence at full power input at low frequencies.

 

 

4645B Single 460 mm (18”) Subwoofer System

 

COMPONENTS:

JBL Model 2242H 460 mm (18 in)

Low Frequency Transducer

 

SYSTEM: Rated Impedance: 8 ohms Minimum Impedance: 8.0 ohms

 

POWER HANDLING CAPABILITY:

Continuous Pink Noise: 800 Watts

Continuous Program: 1600 Watts

Peak Power: 3200 Watts

 

OUTPUT CAPABILITY:

Axial Sensitivity:

50 Hz to 500 Hz: 99 dB @ 1W, 1m

40 Hz to 100 Hz: 97 dB @ 1W, 1m

Maximum Power Compression:

At -10 dB power (80 W): 0.6 dB

At -3 dB power (400 W): 2.0 dB

At rated power (800 W): 3.3 dB 

 

FREQUENCY RESPONSE :

Lower Frequency limits (no EQ): -10 dB: 18 Hz -3 dB: 35 Hz

Lower Frequency limits (with EQ): -10 dB: 20 Hz -3 dB: 22 Hz

Recommended Crossover Frequencies:

High-Pass: 20 Hz. 24 dB/octave
Low-Pass: 80 Hz to 120 Hz. 12 to 24 dB/octave

 

ENCLOSURE:

Materials and Finish: 19 mm (3/4 in) particle board with 25 mm (1 in) baffle and back panel.

Extensive bracing on all panels.

Enclosure Tuning Frequency: 25 Hz

Net Internal Volume: 225 liters (8 cu. ft.)

Dimensions: 1010 mm x 674 mm x 450 mm H x W x D 39 3/4 in x 26 1/2 in x 17 3/4 in

Shipping Weight: 65 kg (151 lbs)

 

 

Note - the left port came loose while I was moving it and I haven't put it back on yet.  It just needs some glue.  You can see the port in the picture.

 

 

[HiFi Heaven]

WOW!  I had a similar JBL 4648A briefly, installed into a Minneapolis church. Did the job!

 

Here's a question for you BASS FREAKS:  Why not discuss Gain Compression?  The JBL specs reveal 3.2 dB Power Compression at rated Power!

At least JBL admits their actual specs exist only in an ideal theoretical netherworld - not in the real acoustic world. See Notes #5 & 6 on the specs.

https://www.jblpro.com/ProductAttachments/4638.pdf

[Audible Nectar]

I use two of these as subwoofers in my Cornwall theater. I lucked out and got them from a JBL "tent sale" years ago (survivors of the Northridge earthquake IIRC). I use a parametric EQ to smooth out the response, and get impressive performance down to 25 hz. While not truly "subwoofers" in a true technical sense, they function very well as such - having tried other subwoofer options before settling on these.

 

As for power compression, the 3.2db is at the 800W rated power - when using two of them in a 14 x 24 foot room, it's akin to using a nuclear bomb as a flyswatter - so they never see that kind of power here. They have an easy life in the current roomspace, never needing to work very hard to do what I need them to do. They add tremendous scale to the audio performance, and I could never match the performance at multiples of what I paid for mine.

[Schu]

- when using two of them in a 14 x 24 foot room, it's akin to using a nuclear bomb as a flyswatter

So your sayin it would work.

[Audible Nectar]

 

- when using two of them in a 14 x 24 foot room, it's akin to using a nuclear bomb as a flyswatter

So your sayin it would work.

 

 

They do. It required several days work in setup, though - using test tones, microphone, and parametric EQ. Without the EQ, they were these uncontrollable beasts that were wayyyy out of balance with the rest of the system. But with the EQ - as well as some good advice on this forum on how to approach that - I got them to a place where these beasts blend seamlessly with the rest of the system, and with effortless power and depth that a Heritage HT demands. Short of a Tuba HT, Danley, or something similar, these seem an excellent option in a smaller package. Not easy to set up though - I spent hours reading - researching about the parametric EQ and how to use it, and some long days doing the measurements and getting it in tune with the room and system. I am still in that same room and system, though - so I only had to do it once, and it has been well worth all the work.

 

Not good below 20 hz, though - but I have achieved 25 hz at about 4db down at high output, while removing all the peaks. Achieved a nice "house curve". I cut the signal below 20 hz to avoid stressing the woofers from overexcursion. If one wants to go below that, these cabs aren't made for that.

 

There were a number of us who jumped on these during that tent sale, and some good advice was exchanged here on how to use them. Some moved on to other things, some of us ended up rather "blissed out" by what we could accomplish with so little invested.

[pat_in_dfw]

I had them set up where they were flat down to around 30hz with some help from a parametric EQ.  These are meant to pump out a LOT of bass for a commercial movie theater, but with the right setup they can be some pretty powerful subs in a traditional home theater.  I have 2 kids now and I haven't really sent a good signal through them in almost 5 years.  I'm moving and downsizing so these need to find another home.

[J M O N]

I lucked out and got them from a JBL "tent sale" years ago (survivors of the Northridge earthquake IIRC).

 

These are actually what caused the earthquake!

 

They are definitely monsters and don't require much power.  if you were looking for a "sub" to keep up with your Klipschorns, they can do it (even though they are technically not a sub but they will shake your house) -- although for Klipschorns you might want more than one.  These have plenty of output, but having more than one will allow each driver to move less thus producing cleaner sound.  These are not one-note bass bins, they will sound like the signal that comes in (within their range).  They are passive and will require an amp.  Tom B. provided much info on these including how best to set them up and many took advantage of the deal and his tips.

[pat_in_dfw]

I love the positive comments, but I still have them and I'm moving soon and don't want to have to find a storage building for these when I move.  Anyone interested?

[Thaddeus Smith]

How many are you actually selling for the listed price?

[CECAA850]

How many are you actually selling for the listed price?

 

 

I've always thought there was one for sale up till his last post where he stated "them".

[Ceptorman]

I think it's for 1 enclosure with 2 speakers in it, that's why he's referring to it as "them"

There's only 1 enclosure in all 3 of his photos. I could be wrong, it's happened before

[pdawidowski]

thats a beast . 

[pat_in_dfw]

Yes - by "them" I was referring to a single cabinet with 2 drivers.  Didn't mean to confuse anyone.  Should have said "it" instead of them.

 

Anyone interested?

[pat_in_dfw]

bump after editing post to reflect what I actually have.  I did have 4 of the 4648s and a single 4645 and the now reflects what I have left.