View Full Version : Anyone know anything about JBL Synthesis Equalizers?

10-03-2008, 09:28 PM
I just saw this set on ebay:


I can't find any info about them. Are they any good?

Mr. Widget
10-03-2008, 09:49 PM
The new ones are significantly more powerful. These older EQ's and crossovers are Ranes that were built to JBL's specifications. I am not sure how much better they are than stock Ranes.


10-04-2008, 08:41 AM
I may be able to track down some partial links. As mentioned, they were made by Rane, (stamped on the circuit boards, etc.) and while there were similar somehat equivalent ones in Rane versions, the biggest differences i cam across is that the Rane modes all use 6/12 dB sensitivity selection switches, the JBL's use 3/6 dB.

I'll see if I can find more info later. I've got a JBL unit with 5 regular GEQ's plus 2 sub EQ, (1/6 octave on subs!), plus power, etc.


Mr. Widget
10-04-2008, 10:42 AM
Are they any good?I guess it depends on your application. I'd say that for HT work, which was their intended application they are still quite usable, however for a high quality music playback system, I'd pass.

I have used these older JBLs and the Ranes of similar vintage in HT and was reasonably satisfied. That said, today I would seriously consider this option if you want a really effective equalizer... and it does so much more: http://www.audyssey.com/soundequalizer/index.html


scott fitlin
10-06-2008, 10:19 PM
Another Harman subsidiary company that makes a KICK ASS sounding EQ for economy budgets, DBX! The DBX 2231, 1/3 octave cut/boost EQ, 2 channel, around $500 or so, SOUNDS GOOD. I like this better than my expensive BSS 960, and less costly 966.

Warm, and full tone, not metallic sounding in top end. It works. for $500 you can't go wrong.

JBL 4645
10-07-2008, 08:03 AM
The new ones are significantly more powerful. These older EQ's and crossovers are Ranes that were built to JBL's specifications. I am not sure how much better they are than stock Ranes.


General8-Channel input, 8-channel output, 112-band parametric EQDelay adjustment for each output24 Bit DSP96kHz sample rate on all inputs and outputsBalanced or single ended (unbalanced) inputs and outputsMaximum Input Signal20dBu with 0dB input gain (+8dBu with 12dB gain)Maximum Output Signal Level+19dBuFrequency Response (+0.5/-1dB)20Hz to 20kHzTHD<0.01% (20Hz to 20kHz, +10dBu output)Power Consumption<35VAPower Supply Input85-270V AC, 50/60HzPower Supply50 Watts MaximumBTU Per Hour170 BTU MaximumDimensions (H x W x D)1-3/4" x 19" x 9-1/4" 44mm x 483mm x 235mmWeight6.5lb/3kg

10-08-2008, 08:17 AM
Jbl put out a new model out last September the sdec 4500

the most interesting is the new software the Harman audio test system

with a technology described in Floyd Toole new book sound field management
it really looks a step up in sound processing for the small rooms

The JBL Synthesis SDEC-4500 is the most advanced digital equalizer ever offered by the brand. It optimizes the performance of a JBL Synthesis system in any room, using more than 200 bands of fully parametric digital equalization that can be adjusted from 1/100 octave to 4 octaves wide at +15dB to – infinity, between 20Hz – 20kHz, to correct dips and peaks throughout the frequency range.

In all rooms, there are powerful resonances that emphasize some frequencies and attenuate others. The
SDEC-4500 compensates for these irregularities with far greater precision than has ever been available before, to deliver extraordinary sonic accuracy that meets or exceeds the standards for professional theaters.

The SDEC-4500 is improved from previous models; it’s now capable of applying more precise equalization, with a greater number of adjustable frequency bands, to all of the main, center and surround loudspeakers in a home theater system, and to multiple subwoofers.

The SDEC-4500 also offers an easier-to-use PC “control panel” interface and numerous additional enhancements, including automatic arrival-time calibration for all the loudspeakers and drivers in a multichannel system; an improved Auto-Film-Screen-Compensation feature that automatically corrects for the attenuation in high-frequency output that can occur when a loudspeaker is located behind projection screens of various materials; automatic control capabilities with other JBL Synthesis components; and many other versatile features.

Because no two rooms are alike, the Harman Audio Test System, which interfaces with the SDEC-4500 (and other JBL Synthesis equalizers), allows a JBL® factory-trained-and-certified technician to custom-fit the sound of a Synthesis system to the room in which it is installed.

The Harman Audio Test System is a powerful 16-channel audio analyzer optimized for measuring loudspeaker and room interactions. The analyzer can be configured for either eight-input/eight-output operation, which is ideal for calibrating home theater systems, or for 12-input/four-output operation, which is well suited for use in an anechoic chamber or for car-audio-systems development.

The Harman Audio Test System uses multiple microphones (eight for a JBL Synthesis system) to measure different locations in a room, and applies proprietary digital-signal processing to analyze and correct for the room’s frequency dips and peaks.

The Harman Audio Test System supports 48kHz and 96kHz sample rates, with 20-bit resolution. Its input channels can be used as microphone inputs (with phantom power), or as line-level inputs. All 16 channels of A/D and D/A conversion take place in the Harman Audio Test System hardware, which interfaces with a PC and an SDEC-4500 (or other compatible JBL Synthesis digital equalizer) via Ethernet connections.

When used in a JBL Synthesis system, the Harman Audio Test System enables the achievement of flat in-room frequency response, or frequency correction to any desired target curve. Additional functions include automatic crossover optimization between the main speakers and the subwoofers in a multichannel system; automatic loudspeaker-level calibration; and a newly developed sound field management algorithm that minimizes the seat-to-seat variation in bass response in a home theater system to a far more effective degree than do other hardware and software solutions.