surround speakers seem to sound dull when running dolby ex (7.1)

[Astro]

at the moment i have an rx-v2500. when ever i set the amp to dolby digital ex (to run the surround back speakers as well as the surrounds, i find that the normal surrounds seem to mute slightly and sound like a blanket has been put over the top (not as bright sounding). when i put it back to 5.1 they sound better. why is this?

[Sir Terrence the Terrible]

at the moment i have an rx-v2500. when ever i set the amp to dolby digital ex (to run the surround back speakers as well as the surrounds, i find that the normal surrounds seem to mute slightly and sound like a blanket has been put over the top (not as bright sounding). when i put it back to 5.1 they sound better. why is this?

Two things going on here. When you kick in to 6.1+1(Dolby EX) the reciever is compensating for the volume that two extra speakers will have. Your surround speakers should have a total output of 82db per side(L and R seperate), so when combined together(in terms of output) they should equal 85db total. When you add in another two speakers, the total volume of all of the surrounds would be 88db, which is too loud when referenced to the front. So what your receiver is doing is dropping the side surrounds down 3db to compensate for two more speakers(80db per side), and the total output of all four would equal to 85db, which is the correct volume. Each surround speaker would have a referenced output of 80db, so when all four are combined the total output would be 85db, which would be equal to each of your front speakers. Its a balancing measure within the Dolby curcuit.

Secondly, when you kick in the EX curcuit, it directs signal to the center rear channels, which mean taking a bit of high frequency information from the sides, and sending it to the rear. That is what makes it a bit dull when compared to 5.1 where it is directing no signal to the center rear.

So that should explain of your mute and dull problem. Nothing wrong with your reciever, it just the way the EX curcuit works.

[Astro]

Two things going on here. When you kick in to 6.1+1(Dolby EX) the reciever is compensating for the volume that two extra speakers will have. Your surround speakers should have a total output of 82db per side(L and R seperate), so when combined together(in terms of output) they should equal 85db total. When you add in another two speakers, the total volume of all of the surrounds would be 88db, which is too loud when referenced to the front. So what your receiver is doing is dropping the side surrounds down 3db to compensate for two more speakers(80db per side), and the total output of all four would equal to 85db, which is the correct volume. Each surround speaker would have a referenced output of 80db, so when all four are combined the total output would be 85db, which would be equal to each of your front speakers. Its a balancing measure within the Dolby curcuit.

Secondly, when you kick in the EX curcuit, it directs signal to the center rear channels, which mean taking a bit of high frequency information from the sides, and sending it to the rear. That is what makes it a bit dull when compared to 5.1 where it is directing no signal to the center rear.

So that should explain of your mute and dull problem. Nothing wrong with your reciever, it just the way the EX curcuit works.

ok thanx for the very helpfull reply!
i might play around with it and even turn up the level of the surrounds on the reciever and see how that goes.
Because this happens, to me the 5.1 setup sounds better. When the reciever takes some high frequency info from the surrounds and sends it to the rears as well, i can defenetly hear the high freq drop. Why do people rave about ex and have it set up then?

[pixelthis]

ok thanx for the very helpfull reply!
i might play around with it and even turn up the level of the surrounds on the reciever and see how that goes.
Because this happens, to me the 5.1 setup sounds better. When the reciever takes some high frequency info from the surrounds and sends it to the rears as well, i can defenetly hear the high freq drop. Why do people rave about ex and have it set up then?


I didnt have a problem with my 7.1.
Did you recalibrate the levels of your system when you set up the back speakers?
I THINK YOUR EARS ARE PLAYING TRICKS WITH YOU.
Since the rears are directly behind you there is going to be more high frequency info coming from them, because of their directional nature.
Its not that the sound from your surrounds is "dropping" its that the sound from your backs are so much louder.
I had to turn mine down a great deal in order to get everything equalized out.
Finally decided that bi-amping would be so much more usefull:1:

[Sir Terrence the Terrible]

I didnt have a problem with my 7.1.
Did you recalibrate the levels of your system when you set up the back speakers?
I THINK YOUR EARS ARE PLAYING TRICKS WITH YOU.
Since the rears are directly behind you there is going to be more high frequency info coming from them, because of their directional nature.
Its not that the sound from your surrounds is "dropping" its that the sound from your backs are so much louder.
I had to turn mine down a great deal in order to get everything equalized out.
Finally decided that bi-amping would be so much more usefull:1:

Pixelstupid, stop spreading bad information, you do not know what you are talking about AGAIN!!!

If you know anything about our hearing system, you know that the pinna reflections actually reduce high frequency information from reaching the inner ear. Sounds directly to the sides of us have a more direct path to the inner ear, so high frequencies are not reflected, but maintain's its energy to the highest frequencies we can hear. As you change the azimuth of the signal hitting the ears more rear ward, high frequencies become more and more reflective off our pinna, thereby REDUCING high frequency information.

As part of the EX curcuit, the volume level does drop when you engage the EX button on the receiver. As I have said, if you engage the buttom and the speakers do not drop in level, they will be 3db too high when the output is electrically combined. The EX curcuit compensates for this by reducing the L/R surrounds when the EX speakers are engaged.

When you do not know something, keeping your hands off the keyboard is advisible.

Can you tell me why anyone would bi-amp something that is too loud already? Doesn't make any sense to me.

[SlumpBuster]

I don't want to jump into a dog fight here, but I'm one of the people that would rave about EX. I miss it when I don't use it.

In fact, this weekend I watched "I Am Legend" with a room full of guests and, accordingly, could not sit in my usual sweet spot. I was placed in the back between my back surrounds. To my surprise, everything sounded great. It was fun to listen to my system from a different perspective. The effects were slightly exagerated, but not distracting.

But on to the advice. I haven't noticed any similar problem when running EX. Although I am not as technically informed as SirT, his explanation makes good sense. Regardless of what is causing it, I would still play around a bit with speaker positioning (to the extent that you can) and speaker levels. If you haven't leveled out the speaker volumes with a SPL meter, this would be a good time. Many auto calibration systems are innaccurate, including YPAO.

There isn't anything inherently wrong with EX, nor is it inherently inferior to 5.1. But you are messing with the signal, changing it, expanding it, and essentially distorting it. Accordingly, if it is not implemented correctly, you will miss the benefit potentially muddling the surround field in the process.

Oh, I forgot. The 2500 has a built in graphic equalizer for each channel, try playing around with that. Boost some of the high frequencies to see if you like the results.

[pixelthis]

Pixelstupid, stop spreading bad information, you do not know what you are talking about AGAIN!!!

If you know anything about our hearing system, you know that the pinna reflections actually reduce high frequency information from reaching the inner ear. Sounds directly to the sides of us have a more direct path to the inner ear, so high frequencies are not reflected, but maintain's its energy to the highest frequencies we can hear. As you change the azimuth of the signal hitting the ears more rear ward, high frequencies become more and more reflective off our pinna, thereby REDUCING high frequency information.

As part of the EX curcuit, the volume level does drop when you engage the EX button on the receiver. As I have said, if you engage the buttom and the speakers do not drop in level, they will be 3db too high when the output is electrically combined. The EX curcuit compensates for this by reducing the L/R surrounds when the EX speakers are engaged.

When you do not know something, keeping your hands off the keyboard is advisible.

Can you tell me why anyone would bi-amp something that is too loud already? Doesn't make any sense to me.


Third grade math doesnt make sense to you.
I HAVE A CHOICE OF A 7.1 SYSTEM or to use the two "back" amps for B speakers,
which I can use to bi-amp the fronts, decided that I would go that way.
And My ex system didnt act the way you describe, dont think ANY of them do,
so keep YOUR fingers off the keyboard , wiseguy:1:

[pixelthis]

I don't want to jump into a dog fight here, but I'm one of the people that would rave about EX. I miss it when I don't use it.

In fact, this weekend I watched "I Am Legend" with a room full of guests and, accordingly, could not sit in my usual sweet spot. I was placed in the back between my back surrounds. To my surprise, everything sounded great. It was fun to listen to my system from a different perspective. The effects were slightly exagerated, but not distracting.

But on to the advice. I haven't noticed any similar problem when running EX. Although I am not as technically informed as SirT, his explanation makes good sense. Regardless of what is causing it, I would still play around a bit with speaker positioning (to the extent that you can) and speaker levels. If you haven't leveled out the speaker volumes with a SPL meter, this would be a good time. Many auto calibration systems are innaccurate, including YPAO.

There isn't anything inherently wrong with EX, nor is it inherently inferior to 5.1. But you are messing with the signal, changing it, expanding it, and essentially distorting it. Accordingly, if it is not implemented correctly, you will miss the benefit potentially muddling the surround field in the process.

Oh, I forgot. The 2500 has a built in graphic equalizer for each channel, try playing around with that. Boost some of the high frequencies to see if you like the results.

Glad you like your system.
I made a booboo and said that the back channel was discrete, its actually summed
from the difference info from the surrounds, havent messed with this for awhile.
ANYWAY thats where they got the center channel on old prologic systems.
But wasnt much distortion on those systems , shouldnt be much on this type of system.
WHICH REMINDS ME OF A TRICK that was started when DD came out.
PEOPLE WOULD TAKE THEIR OLD pro-logic receivers and run the back surrounds into the left and right front, and that would be their rear amps.
Then they would take the output from the center, that would be their "back" channel.
This gave them a 6.1 system on the cheap, some sounded quite good:1:

[Sir Terrence the Terrible]

Third grade math doesnt make sense to you.
I HAVE A CHOICE OF A 7.1 SYSTEM or to use the two "back" amps for B speakers,
which I can use to bi-amp the fronts, decided that I would go that way.
And My ex system didnt act the way you describe, dont think ANY of them do,
so keep YOUR fingers off the keyboard , wiseguy:1:

All EX systems work the way I describe, Its in the Dolby standard for EX channels. If you spent less time dumpster diving, and more time reading Dolby's white papers on EX you would know this. Some receivers handling the process differently than other, but in the end the result is the same.

Since your ability to think is hampered by the fact you don't have a brain cell left to use, just don't do it.