i just hooked up a velodyne 3750r sub. it is the first sub i have owned. a couple of questions. 1 when the reciever is set to stereo i hear no bass from the sub only the speakers but when i go to any other setting(arena, jazz etc. or pro logic, neo cinema etc) i get plenty of bass. why is this?
2 my manual says"Subwoofer Direct
Subwoofer Direct is a setting on the low-pass crossover knob and will allow frequencies up to 200 Hz into the subwoofer. See below for a more detailed explanation of this feature. Your Velodyne DLS-R subwoofer is designed to operate using the full range audio signal for input when using the built-in crossover (controlled by the dial on the back panel). Many home theater processors/receivers (Dolby Digital, DTS, THX) have a "subwoofer out" jack that performs this same function and are designed to be used with a powered subwoofer.
In these installations, you may want to bypass the crossover in either the processor or the Velodyne subwoofer. In some cases, you may want to use BOTH crossovers. To do this, you can use both your processor's crossover and the one internal to the Velodyne sub. You should stagger the frequencies (i.e., 120 Hz subwoofer, 80 Hz processor) for best results.
To bypass the subwoofer's internal crossover when the unit is being fed a low pass signal from another crossover, simply locate the knob marked "LOW-PASS CROSSOVER" on the rear panel of the subwoofer and turn it counterclockwise to the "DIRECT" position. This will eliminate the internal crossover from the signal path. " what does this mean? i have a "lfe" out to lfe in on the sub, that is how it is connected. thanks
In the first instance, the processor in your receiver simply doesn't allow subwoofer output when using a stereo source. (Kind of a pain since most TV source material and Redbook CD is in stereo.) This is typical of most CD players and processors, particularly when using a digital output from the player to the receiver/processor. You can switch to an analog connection which should provide subwoofer output but you will give up the "quality" (?) of the digital connection. If you have a DVD/SACD/DVD-A player which feeds to the processor via the analog 5.1 inputs, you get to choose what happens with the sub in the set up menu for the player. (If your receiver/procesor has 5.1 analog inputs, even if you're using a stereo player, swap your CD player connection to "Front L/R" and you will probably have a subwoofer in stereo. You will also have better sound overall going into the 5.1 analog inputs, even in stereo.)
Otherwise, with a conventional two channel CD player, you get to either forget the sub in stereo or you can run the subwoofer off your main front speaker outputs which will make the sub active whenever the system is operating. If you run from the speaker outs, beware of a peculiarity in Dolby Digital source material (which apparently exists in most processors) whereby the dynamic range is compressed several dB when you set up the 5.1 system without a subwoofer. (You would set your menu to "Large" front speakers, no subwoofer, when running the sub off the main speaker output.)
Overall, it is probably better to live without the sub in stereo. Use the least obnoxious matrixed audio if you want a subwoofer with stereo source material. (Seems a bit of a Catch-22 and doesn't elicit the best of feelings about shelling out large sums for a system that more often than not works against your best intentions.)
The "Direct" input on your subwoofer simply bypasses the crossover in your sub's plate amp in order to allow just one setting for the roll over (low pass/high pass) frequency from main speakers to sub. If you have controls on your processor which allow sufficiently fine control (5Hz increments) to set the sub/main roll over frequency to your taste, you should use the "Direct" setting and only set the roll over at one location. Using "Direct" will allow you to set the roll over at the processor only and will ignore the crossover in the sub.
The bit about using both filters staggered together is a bit dicey and isn't really where I would go at this point. What happens with a processor set to 80Hz and a subwoofer set to 120Hz is a slow roll off of the signal from the processor to the subwoofer output starting at 80Hz and above. At 120Hz the subwoofer's filter kicks in and the roll off becomes substantially steeper with both filters now taking effect. At this point the roll off above 120Hz would be quite steep but not exactly what you might desire.
I think, to begin at least, it is best to set the sub to "Direct" and use only the processor's filters. This will, in all likelyhood, give you a smooth transition from sub to main speakers with little boost or cut at any specific frequency. By calling the setting "Direct", the subwoofer manufacturer has simply given a fancy name to the way most other subs operate. Conventional wisdom which sets the roll over at only one location is the best way to begin experimenting with how to set up your system.
If you decide from the first explanation above to run your sub off the speaker outputs, then you would only control the sub's roll over with the sub's own crossover control. The processor would be set to "Large" front speakers and the option to switch on the sub output will probably be negated in the processor. If you have the option for "Sub on/off" after setting the main speakers to "Large" choose "sub off". This will send a full range signal from the speaker outputs.
Otherwise, if you are running the sub from the processor's "LFE" or "sub" output, set the sub's control to "Direct" and make your adjustments for roll over only at the processor. For the most part, your ears get to decide what sounds best as there are no real standards for a plain ol' home theater, only THX which demands a subwoofer.
And, welcome to the wonderful world of home theater where almost anything is possible and you get to decide what sounds best.
got the sub to play with cd's and any stereo setting. velodyne told me to make sure my main speakers (bose 701's) were set to small. but with a sub the reciever only allows normal and large. i set it to normal and set the rest of the set up per reciever manual and, voila, bass in evey mode. don't make fun of the bose. i spent 12 grand in equipment this year (plama tv's etc etc) and the wife just won't let me spend 2500 right now for a pair of b&w tower speakers.