System Setup Question

[Retread]

I have the Pioneer VSX-D912 Receiver, the Ventriloquist, and the VTF-3R. There is not enough information in the manuals of any of these things to know precisely what is going on.

(1) The receiver can be set so the front speakers are "Large" and the sub is "Plus." Am I correct that this setting will disable the receiver's internal crossover for the front and sub and send the full frequency range to both the front speakers and the sub?

(2) If I am correct about (1), what will the sound pressure roll-off be like on the Ventriloquist front speakers and what will be the consequences of this setting on Ventriloquist distortion?

[wid]

I just hooked up my ventriloquist system 3 days ago.I set all speakers to small, hooked up the sub through the lfe out and set the crossover to 100hz.What is recomended is a 80hz crossover but my recievers lowest setting was 100hz.Man I tell ya this system really sounds GREAT.This is my first HT system, but I also have a 2CH system that I have about 6K invested in,so I am not a stranger to what sounds half way decent.To anyone thinking about the VT-12 stop thinking and go for it

[Retread]

I'm an electrical engineer with a Ph.D. who's been in the business about 50 years, counting the time I worked as a lab tech as an undergraduate. It drives me crazy not to know how things work and not to have technical data.

Running various signals and measuring the response of the system using various microphones tells me the combination of small and VTF-3R leaves a significant hole between 80 Hz and 100 Hz.

I know people say they don't hear the hole, but knowing there is a hole drives me crazy. "Sounds great" and "plays loud" doesn't answer the mail.

I didn't pay attention to audio for about 20 years until I got interested in home theater and am now having to catch up on the technology. I'm also twice retired and still working about 2500 hours a year. Hence, "Retread."

[Lwang]

In addition to measuring with mics, you would have to measure the voltage output from the receiver's binding post. This would allow you to determine where the main speaker actually starts rolling off. Plus you could hook up a scope and trigger the signal on some other constant source (analog out of a signal that has not passed through the bass management) so that you could determine the phase shift at the freq in which they are crossing over, this way, you could vector sum the two signals to see that they are electrically flat.

If you set the VT-12 to large, is there still a dip in the response between when the signal traverses from 100hz to 80hz?

Also, with the mic setup, hooking it up to some analyzer like a scope or analyzer to see if the accoustically summed soundwave are in or nearly in phase (this time, trigger it to the receiver's speaker output if you want to have absolute electrical to accoustical relation), if there is a significant phase anomaly in that range, you might want to play around with the sub's polarity switch and/or play around with its placement so there is minimal phase shift from the transition of the VT-12 to the sub.

[Retread]

"In addition to measuring with mics, you would have to measure the voltage output from the receiver's binding post. This would allow you to determine where the main speaker actually starts rolling off."

I had imagined that "Large" sent the full frequency spectrum to the speakers set that way. Your answer seems to imply this is not necessarily so.

If what I had imagined were true, then the Ventriloquist center speaker would be hit with frequencies all the way down to sub-audio, and its rolloff and distortion properties would be directly relevant. One of the virtues touted by Hsu for the Ventriloquist center speaker is extended frequency range to bridge the gap to the sub. But with the receiver internal crossover set to 100 Hz, that doesn't pertain.

In any case, I think Hsu Research should post the roll-off and distortion properties of the Ventriloquist center speaker when fed with the full frequency spectrum. Free space, close-mic, whatever. Some data is better than no data.

[Sorny]

With the receiver set to small and crossover frequency of 100Hz, the Ventriloquist center speakers is very much active. The "hole" usually found in micro systems is from ~80Hz on the low end all the way up to ~250Hz. The Ventriloquist center is designed to go from ~80Hz up to 20KHz, and as such, to not have a hole like other micro systems.

Make sure the crossover is "out" on the VTF-3 and the crossover knob turned all the way up. Then, make sure your ventriloquist center is enabled via the switch on the back. Any "hole" left at ~80Hz to ~100Hz is a phase issue due to the crossover. Move the sub and play with the phase dial to get rid of it.

Long story short, run the Ventriloquists as "small". How anyone could think a 2.5" driver is full range just boggles my mind... :)

Sorny

[Retread]

Originally posted by Sorny
Long story short, run the Ventriloquists as "small". How anyone could think a 2.5" driver is full range just boggles my mind... :)

Sorny

The Ventriloquist center speaker has a pair of 4"x6" drivers. Unless I've grossly misunderstood the system, all of the signal from the receiver's front-three go to the center speaker, where the lows are split from the highs, the lows from all three channels are mixed and sent to the 4x6s, and the highs go to the 2.5" tweeters in the center and two front satellites.

Hsu's products page assert that the Ventriloquist has a response from 80 Hz to 20 KHz. I'm asking whether that 80 Hz is the start of the roll-off (or perhaps the 3dB point), how many dB per octave it rolls off, and what the distortion properties are for the Ventriloquist alone if the full range is applied to them. Nobody seems willing or able to address this question.

[Dudley]

Check on the BIC America web page there may be some info, you could also e-mail BIC - they will respond.

Obviously the BIC version does not have the ventriliquist feature, but the low extention should be about the same.

[Lwang]

Once you measure the electrical properties of the "Plus" output to the sub, then you could tell what is sent to the sub.

Hsu's products page assert that the Ventriloquist has a response from 80 Hz to 20 KHz. I'm asking whether that 80 Hz is the start of the roll-off (or perhaps the 3dB point), how many dB per octave it rolls off, and what the distortion properties are for the Ventriloquist alone if the full range is applied to them. Nobody seems willing or able to address this question.
If it is a sealed design, then the rolloff would be 12dB/oct. If it is ported, then it would be 24dB/oct. freq resp spec usually indicates the -3dB point, unless then are fanatical like Hsu and quote a tighter spec.