frequency response for VT-12 sats

[doc kracken]

Hi,
I am wondering what the frequency response is for the sats in the ventriloquist system. I am interested in this system but without a tweeter how can it reproduce the highs.
Thanks for any info.
Also would like to know the frequency range for the center :)

[Retread]

Originally posted by doc kracken
Hi,
I am wondering what the frequency response is for the sats in the ventriloquist system. I am interested in this system but without a tweeter how can it reproduce the highs.
Thanks for any info.
Also would like to know the frequency range for the center :)

Yes, I've been asking similar questions for a while and been getting no answers. The Product Page says the Ventriloquist has response down to 80 Hz, but doesn't say what that means, nor have I seen any specs on distortion properties in that region.

I've run spectrum sweeps using TrueRTA and the high end seems OK.

[Stats]

Here's what's listed at Gateway (I assume it's the same system):

Satellite
Crossover Frequency 150 Hz
Frequency Response 150 Hz to 18.5 kHz, +/- 3dB
Impedance 8 ohms
Recommended Power 10 to 110 watts per channel
Sensitivity 90 dB @ 1 Watt/1 Meter

Center
Crossover Frequency 80 Hz; 150 Hz
Frequency Response 80 Hz to 18.5 kHz, +/- 3dB
Impedance 8 ohms
Recommended Power 10 to 110 watts per channel
Sensitivity 90 dB @ 1 Watt/1 Meter

http://accessories.gateway.com/AccessoryStore/Consumer+Electronics_381930/Digital+TV_381941/Home+Theater+Systems_9000003/1528818_ProdDetail?tpcid=1000&productid=1528818

[Michael Bain]

The Gateway system is probably similar, although most likely Hsu has tweaked the Ventriloquist system to meet their listening demands and to match with their subs.

[Retread]

Originally posted by Michael Bain
The Gateway system is probably similar, although most likely Hsu has tweaked the Ventriloquist system to meet their listening demands and to match with their subs.

Why are we using words such as "probably" and "likely" about something as fundamental as the specification for frequency response of a speaker system? Why doesn't Hsu post the information?

It reminds me of an event in 1962 when I had the responsibility for environmental testing of Apollo spacecraft electronic equipment. I had a 10,000 force-pound shaker with which vibrate objects (talk about a big magnet assembly! About 4' long and 4' in diameter. We had to wear hard hats, because it kept making pieces of concrete fall off the ceiling). A "high-envionment" telemetry recorder ($25,000 in 1962!) would go to 15% flutter at 1G. Everyone said that couldn't be possible, so I was sent to the factory in LA. They rented a shake facility and found that it was worse than I had said. When I asked for an explanation, they said they had never shaken the entire recorder as one assembly, because their shaker wasn't big enough.

So, with specifications not forthcoming, I wonder if Hsu has actually done the measurements.

[Michael Bain]

I was not talking about frequency response, I was talking about ultimate performance of the systems. Since we know even less about the Gateway system, we have to use words like "probably" and "likely" when comparing to VT system.

What exactly is it about the specifications that you want to know that is not already being told? It doesn't make much sense to list the frequency response of the small satelite speakers because the center channel is designed to handle the lower mid bass load, and the overall system is designed to be used with a subwoofer crossed at 80-100Hz.

There is good info on the VT series here:

http://www.hsuresearch.com/forum/showthread.php?s=&threadid=248

Hsu always measures his products, usually very painstakingly and very conservatively. That is without question.

[Retread]

Originally posted by Michael Bain
I was not talking about frequency response, I was talking about ultimate performance of the systems. Since we know even less about the Gateway system, we have to use words like "probably" and "likely" when comparing to VT system.

What exactly is it about the specifications that you want to know that is not already being told? It doesn't make much sense to list the frequency response of the small satelite speakers because the center channel is designed to handle the lower mid bass load, and the overall system is designed to be used with a subwoofer crossed at 80-100Hz.

There is good info on the VT series here:

http://www.hsuresearch.com/forum/showthread.php?s=&threadid=248

Hsu always measures his products, usually very painstakingly and very conservatively. That is without question.

The questions I have been asking, over and over, are: (1) is the 80 Hz frequency the 3 dB point or further up the curve; (2) what is the roll-off rate; and (3) what are the distortion properties if the center and front are set to "Large."

As far as I can tell, a Hsu person has not responded to these questions. The answer I always get is from someone else, and it's always something like "Why would you want to set the center and front to Large?" And "Don't you know that 2.5" drivers can't handle low frequencies?" (as if the center didn't have two 4"x6" drivers). And "What you REALLY should do is set the fronts to Small, and . . ." Etc.

I also stated my surmise (since the center and front amplifier cables all go to the center, and the center distributes to the front satellites) that the center speaker splits the lows from the highs, sends the lows to the two 4x6s, and distributes only the highs to the front satellites. No answer to that one either.

Why do I want to know? Because there's a big hole in my responses in the region of 80-100 Hz. I want to know if I'm looking at an attribute of the system, or if I am looking at room artifacts.

I've seen posts saying that there is a hole in the region of 80-100 Hz, but it doesn't affect the "sound." Not a highly satisfying assertion.

So I'm currently faced with running the tests myself, in my imperfect environment, and inferring the correct results.

If I didn't provide my customers with answers to their questions, I wouldn't be in business long.

[Michael Bain]

I suggest speaking with Dr. Hsu (or Sasha) directly about this (call the company and ask for them, or email them).

Hsu does not list a tolerance margin for frequency response of the VT system. Good point. Presumably that is +/-3db window, but talk to tech support and verify that (knowing Hsu's conservative nature, I can basically assure you that he would not spec something with greater than +/-3db tolerance). Also, it really wouldn't make sense for the center to pass off all the mid/high frequencies to the satellites. The center channel is critical for dialogue in the HT setup. The difference between other systems with only small satellites is that the low mid bass load is moved to the center channel where it can properly be reproduced with the larger drivers.

Hsu generally recommends setting all the speakers to small, and then placing the subwoofer in a corner for boundary reinforcement.

Ultimately the goal here is to set up the system to the best of it's ability, no matter what the specifications or distortion measurements are. This will generally require input from Dr. Hsu, who can be most easily reached by phone or email.

Start with this form:

http://hsuresearch.com/support/index.php?id=36

[Sorny]

Why do I want to know? Because there's a big hole in my responses in the region of 80-100 Hz. I want to know if I'm looking at an attribute of the system, or if I am looking at room artifacts.


Have you played with different crossovers than 80 and 100Hz? Have you tried changing the phase? Is the ventriloquist effect turned on via the switch on the center channel? Have you tried the room placement link to see if perhaps there is a null at your seating position at around that frequency?

Just some things to try, if you haven't already...

Sorny

[Lwang]

I also stated my surmise (since the center and front amplifier cables all go to the center, and the center distributes to the front satellites) that the center speaker splits the lows from the highs, sends the lows to the two 4x6s, and distributes only the highs to the front satellites. No answer to that one either.
The mid/high of the center channel does not go to the L&R speakers. They stay with the center speaker, so you get real mono dialogue through the center channel.

If you are concerned about the splitting of the bass & mid/treble of the L/R speaker between the center and the satillites itself, that is the way they are designed. This is done because the bass are rerouted to a center point between the two main speakers, preserving the rough location of the original signal's bass. The imaging of really-off centered instruments might be pulled more toward the center slightly, but what would be the alternative in situations where you have micro-satillites? You can either cross at 250hz to the sub, where in 99% of the case, it would be off centered (either in the front or back of the room). That would have really made the imaging of any istrument with any type of bass pull toward the location of the woofer. Another alternative would have been to cross the sub at 80-120hz range (the most popular freq range). That would leave a big hole between 100hz to 250hz. Plus you would still have the pulling of the image toward the sub since in much of the freq range, the sub's level would still be louder than the satillites, allowing us to localize the transducer that is producing the most sound.

Why do I want to know? Because there's a big hole in my responses in the region of 80-100 Hz. I want to know if I'm looking at an attribute of the system, or if I am looking at room artifacts.
How much hole could you have in the response of the speaker? A sealed speaker like the VT-12's response would drop at a rate of 12dB/oct (after a slow initial transition), So in an absolute worse case situation, a drop in in 1/3 oct would be 4dB. But summed with the sub's crossover of 80hz, it would mean a 1dB drop.

[Retread]

Originally posted by Lwang
The mid/high of the center channel does not go to the L&R speakers. They stay with the center speaker, so you get real mono dialogue through the center channel.

If you are concerned about the splitting of the bass & mid/treble of the L/R speaker between the center and the satillites itself, that is the way they are designed. This is done because the bass are rerouted to a center point between the two main speakers, preserving the rough location of the original signal's bass. The imaging of really-off centered instruments might be pulled more toward the center slightly, but what would be the alternative in situations where you have micro-satillites? You can either cross at 250hz to the sub, where in 99% of the case, it would be off centered (either in the front or back of the room). That would have really made the imaging of any istrument with any type of bass pull toward the location of the woofer. Another alternative would have been to cross the sub at 80-120hz range (the most popular freq range). That would leave a big hole between 100hz to 250hz. Plus you would still have the pulling of the image toward the sub since in much of the freq range, the sub's level would still be louder than the satillites, allowing us to localize the transducer that is producing the most sound.


How much hole could you have in the response of the speaker? A sealed speaker like the VT-12's response would drop at a rate of 12dB/oct (after a slow initial transition), So in an absolute worse case situation, a drop in in 1/3 oct would be 4dB. But summed with the sub's crossover of 80hz, it would mean a 1dB drop.

I thought the center speaker in the Ventriloquist is ported.

My receiver has a 100 Hz lowpass filter. I don't know its rolloff characteristics, but I suspect it's fairly steep. I'll eventually measure it to see. The only way to disable the receiver lowpass is to set the front to Large. If I understand correctly, that applies the full bass to the front. I'd really like to know what kind of distortion results from applying full bass to the Ventriloquist center speaker. If I set the front to Large and subwoofer to Plus, then the front bass is sent to the front and also to the sub.

I'm not "concerned" about splitting the bass in the front center. Since all the sound in the front goes to the center, and the front satellites are small, then there has to be bass splitting and redirecting in the center. I'd just like to know what.

[Lwang]

I'm not "concerned" about splitting the bass in the front center. Since all the sound in the front goes to the center, and the front satellites are small, then there has to be bass splitting and redirecting in the center. I'd just like to know what.
What do you mean "what"? crossover freq? xo type? splitting/bass summing method?


As to the VT-12's bass design, I don't see the port in these pictures:

http://www.hsuresearch.com/forum/attachment.php?s=&postid=2256

http://www.hsuresearch.com/forum/attachment.php?s=&postid=1436

[Retread]

Originally posted by Lwang
What do you mean "what"? crossover freq? xo type? splitting/bass summing method?


As to the VT-12's bass design, I don't see the port in these pictures:

http://www.hsuresearch.com/forum/attachment.php?s=&postid=2256

http://www.hsuresearch.com/forum/attachment.php?s=&postid=1436

There are two ports on the back of my center speaker. I assume one for each 4x6. I seem to recall a Sasha post a while back that the model for the pictures wasn't the real thing.

As for wanting to know "what," the answer is as much as I can get.

[wid]

I dont have any answers to all your tech questions , but my VT-12 center speaker does not have those two ports on the backside you say you have on yours.Are you sure about those ports?

[tdekany]

Originally posted by wid
I dont have any answers to all your tech questions , but my VT-12 center speaker does not have those two ports on the backside you say you have on yours.Are you sure about those ports?

I have them on mine. (girlfriends). I'll take pictures next week.

[wid]

Tdekany, I just checked my center speaker agian ,I looked in back, under it, and even took the grill off and there is no ports.So this means either there is two different Vt centers or one or the other is a mistake.I am going to e-mial HSU and try to get an answer to what is suppose to be right.

[tdekany]

they are up in the corners.

[wid]

Nothing in the corners either

[Lwang]

Can you verify that they are in fact ports? You could block one and blow mildly into the other. If the woofer moves out, then it is in fact ports.

[tdekany]

I am sure now that I am wrong. They look like they could be ports. I am sorry if I misled anyone.

[wid]

No worries, just sit back and enjoy this wonderful sounding system.The more I let others check out the VT-12 the more I am satisfied its not just me that thinks this system is so GOOD sounding.

[Retread]

Originally posted by Lwang
Can you verify that they are in fact ports? You could block one and blow mildly into the other. If the woofer moves out, then it is in fact ports.

See Sasha's post of 11/13 under "Ventriloquist Launch Details." Here's what he said: "Yes, we decided not to port the small satellites. There were some earlier pictures showing ports. The center channel will have ports on the rear."

[haionlife]

Well, I can only speak for the center that I have...but it has 2 ports on the upper outer corners of the rear cabinet face. Looked a lot like ports and I even stuck something down in them to snag out a bit of stuffing...Then after reading this thread and having doubts I decided to gather a bit of evidence. I have a CD that has single frequency sine waves and I threw on some in the 70-80hz range and cranked the volume...

"Yep, them are ports!" I exclaimed - as the Kleenex brand facial tissue blew across the room. There was a good breeze coming out of each hole. So either they're ports or there's a manufacturing defect!!! Uh oh! I'll just go ahead and assume that its a feature and not a bug :)


Mark