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This topic has 2 voices, contains 5 replies, and was last updated by avatar Jason Hicks 1073 days ago.

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May 13, 2011 at 12:35 pm #2558
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Michael
I'd like to get opinions on how much power the VGT's really need. For instance, the sr7005 claims 125w per channel. Would that be enough to get good sound out of the VGT's at low to mid volumes? I've read some reviews that suggest the VGT's need a lot more power than is delivered through an "affordable receiver" – though they don't make a recommendation on how much power, or whether that means separate pre/pro & amp. (Thinking ahead to a time where I may consider trading up from VFT's to VGT's).  
 
 
May 13, 2011 at 1:16 pm #2836
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Jason Hicks

[quote user="Timecop"]

I'd like to get opinions on how much power the VGT's really need. For instance, the sr7005 claims 125w per channel. Would that be enough to get good sound out of the VGT's at low to mid volumes? I've read some reviews that suggest the VGT's need a lot more power than is delivered through an "affordable receiver" – though they don't make a recommendation on how much power, or whether that means separate pre/pro & amp. (Thinking ahead to a time where I may consider trading up from VFT's to VGT's).  
 
 

[/quote]

Well it's going to depend on a few factors, how big your room is, how far you sit from them and what your listening levels are typically.

But keep in mind that the VGTs are more sensitive than the VFTs so they actually will require less power to get the same amount of output. 

If I had to make a catch all generalization I would say that I would recommend an AVR with around 110 to 120 watts/channel to power the VGTs.

I read the review where the guy said you needed a $5000 amp to get the most out of the VGTs and maybe he's right but I wouldn't know since I have never heard the VGTs powered by an amp in that price range, so maybe I've never even really "heard' them properly.  [*-)]

I do know that I just listened to them powered by a Peachtree iNova (2x80W integrated) and they sounded very nice to my ear. 

May 13, 2011 at 2:17 pm #2706
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Michael

When you say that the VGTs are more sensitive than the VFTs, what exactly do you mean?

The room I have these in is 13 x 18, I sit about 12-14 feet away, and not sure how to quantify listening levels really. With the 100w receiver, I was in the low 30's / high 20's – but that felt louder than I usually have to play stuff to get good sound. 

 

 

 

May 13, 2011 at 2:55 pm #2837
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Jason Hicks

[quote user="Timecop"]

When you say that the VGTs are more sensitive than the VFTs, what exactly do you mean?

The room I have these in is 13 x 18, I sit about 12-14 feet away, and not sure how to quantify listening levels really. With the 100w receiver, I was in the low 30's / high 20's – but that felt louder than I usually have to play stuff to get good sound. 

 

 

 

[/quote]

The sensitivity spec tells us the output in dB of the speaker if we feed it one watt and take an SPL reading one meter away from the speaker. 

So the sensitivity of the VFT is 90 dB and for the VGT it is 92 dB.   

Now that might not seem like a big difference, but even a 2 dB difference in sensitivity will have significant implications for how much power you will need to hit a given SPL, especially at higher volumes.

Let's say we are four meters from each speaker and we want to hit an SPL of 95 dB.  We would need about 50 watts for the VFT to hit that SPL.  But we would only need 32 watts for the VGT to hit 95 dB.  If we went up to a desired SPL of 98 dB the gap gets larger, with 101 watts needed for the VFT and 64 watts for the VGT.  So if you are using a 100 watt amp to push the VFT, when you are four meters away we would expect the amp to start clipping right at around 98 dB, as long as you can really get 100 watts out of it.  Keep in mind though that this only is considering direct sound from the speaker, in a normal room you will get more SPL due to reflections from the walls and other hard surfaces.

You could always use an SPL meter to take some readings to figure out what your preferred listening levels are in dB for a given position in your room.

 

 

May 16, 2011 at 11:53 am #2707
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Michael

Thanks for the info Jason, that was very helpful. One follow-up question. I notice that in the Forte system I have, the sensitivity of the speakers are as follows: 

Center: 85 db

Surrounds: 85 db

Towers: 90 db

 

Since the sensitivity is spread out so far between towers and surround/center – does that cause any issues for the receiver? I'm assuming that level-adjustment may correct this by applying a positive push to the speakers with less efficiency… is this how the receiver handles it?

Are there issues when a 5.1 system isn't of matched sensitivity levels?

 

Thanks! 

May 16, 2011 at 2:39 pm #2838
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Jason Hicks

That's correct you can compensate for differences in sensitivity in your system by calibrating the levels in your receiver.  Typically you will have a range of 24 dB to calibrate within, which is more than enough to make up for any sensitivity differences.

Now if you have a receiver that allows you to adjust the levels less than say 10 dB or so, which would only be in older receivers typically, then you could run into problems. 

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