Originally Posted by
coherent_guy
... the amp clipping, first suggested by Grumpy, I believe. I came to this conclusion after connecting one sub1500 in a PSW-D115 enclosure, directly to a Crown CE 1000 amp set to bridged mode, rated at 900 watts/8ohms, 1200 watts/4ohms. The input signal was a test CD with 50Hz, 40Hz, 32Hz, 25Hz, and 20Hz test tones. I was able to drive the sub1500 to the point where there was wind noise from the port, (which is flared inside and out!) which equated to high volume levels, with not one instance of the any distress from the driver at any frequency. I repeated this test with the enclosure sealed as well as I could manage, blocking the port, with identical results, the terrible sounds I heard that started all this never appeared. But this experience has brought new questions to mind, one being, what in the world do you folks that own these woofers drive them with? 1000 watt amps with 1/2 volt input sensitivities? These drivers are very insensitive, or technically speaking, power hawgs!! Connecting the Crown amp driven sub1500 to the rest of my system produced a whimper... where's the bass? I have the level control on the Crown wide open and set to its high gain mode, bridged, and the output level is no where near what the 'D115's plate amp could produce. snip... I used a second preamp for additional gain into the Crown amp, and it's still not enough. The crossover in that plate amp must really put out some voltage, I never had the 'D115's level control set wide open with the plate amp, always between 1/2 to 3/4, FWIW. What am I doing wrong
Thanks everyone...
Your setup sounds like it should definitely put out plenty of power. I'm wondering if something is miswired or set incorrectly? My thoughts bolded below:
I'm sure you have it but here's a link to the CE1000 manual at Crown's site:
http://www.crownaudio.com/pdf/legacy/125645.pdf
As you said, you should have the sensitivity switch on the back panel set to 1.4V (see figure 2.12) that would give the amp the most power for a 1.4V input.
Taken from the manual:
2.6.3 Bridge-Mono Mode
Make sure the amplifier is turned off and the level controls are turned down before you wire the system.
Typical input and output wiring is shown in Figure 2.11.
INPUTS: Connect input wiring to CH 1. (only)
OUTPUTS: Connect the speaker across the positive (+) output terminals. Do not use the negative (–) terminals when the amplifier is being operated in Bridge-Mono mode. Refer to Section 2.5 for output connector pin assignments. Make sure the Mode switch is set to the “Bridge” position when operating in Bridge-Mono mode.
NOTE: Turn down (full CCW) the Channel 2 level control when operating the channel pair in Bridge-Mono mode, as the Channel 1 level control works both channels.
Figure 2.11 shows a single sub hooked up to the left speakon for bridged-mono. I think you should follow the direction, if you hadn't already, to hook the speaker cable directly up to the two (+) outputs on the binding posts. The back of the amp pictorial shows language that says "For Bridged Mono, use ch.1 (+) for (+) and ch.2 (+) for (-) only" I think the figure is at odds with the directions if you leave the speaker hooked up to the left channel speakon connection only. That may be why you are getting such a low output.
I would assume that you have no clipping or fault indicators lighting up on the front. All your input wiring is via 1/4" plug or the barrier wiring is good and not shorted. Lastly, you may want to reverse phase at the speaker just to see if it a phasing problem with the sub and the rest of the system. I don't recall if the SUB1500 driver is a positive or negative for forward cone motion but its an easy check.
Also, if you are summing using a y-cable out of your preamp, could there be a miswire there where the low freq signal is out of phase and cancelled before it gets to the amp?
Something else I found in the manual:
4.1.5 Compression
A full-time compressor is in-line with the signal, reducing the risk of damage to your speakers. I wonder if by trying to feed maximum signal into your amp, its triggering the compressor to limit the signal?
4.3.4 Optional 0.775 V Input - Sensitivity Setting
The CE Series amplifier also provides an optional 0.775 V input sensitivity setting. If you determine that your application requires this sensitivity setting, please contact Crown Technical Support for more information.
That's all I could think of. Hope this helps.
Regards,
Bart