Pioneer Elite 45TX - Volume question

Discussion in 'Archived Threads 2001-2004' started by Steve Vinson, Feb 16, 2003.

  1. Steve Vinson

    Steve Vinson Auditioning

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    I've had a 45TX for about 6 months now. Up until recently, normal listening levels (i.e., with my wife in the room!) were in the 36-33db range - maybe 30. By-myself levels were 27-24db, maybe 21-18db if I was going for broke.

    About a month ago, I changed my sub (built an Infinite baffle). Ever since running the MCACC, normal "wife-approved" levels are now 27-24db. (Right now, we have Chicken Run on at 21db, and it still could not be considered loud.)

    I did not keep track of MCACC levels until after changing subs. (I have since made a simple chart to easily record all the levels.) I suppose the most relevant would be the channel level. Here are my current levels - they have all been relatively similar since I've started keeping records (4 different MCACC's):

    Frnt - L: +8.5
    Cntr: +7.5
    Frnt - R: +8.0
    S - R: +2.0
    SB - R: +8.5
    SB - L: +10.0
    S - L: +6.5
    Sub: -4.5

    BTW, I reset the unit to factory defaults before the last MCACC (which is the one listed here).

    I know I can just turn up the volume to whatever level now works. But, I cannot help but wonder what the difference is. And, I'm not sure I'm getting everything out of my sub that I should be getting. (I'm told my Bryston 4B should be bottoming my 2 15" drivers, but it clips first instead.) The different volume levels make me wonder if the dynamics of the receiver are somehow limited now.

    Any help would be greatly appreciated.

    Steve V.
     
  2. Steve Schaffer

    Steve Schaffer Producer

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    Steve,

    I've done MCACC several times and done some checking afterwards with AVIA test tones and the receiver's test tones, using a RS analog spl meter.

    What I've found is that after the MCACC setup, a volume setting of 0 db will produce an 85db spl meter reading from the reciever's individual channel test tones with the meter held at the same position as the MCACC mike was when the MCACC calibration was run. AVIA test tones will produce 75db spl meter readings at a -15 volume setting for each individual speaker.

    Since you're basing your question on percieved volume levels rather than measured volume levels there are way too many factors involved to come up with a reliable answer.

    You seem to need to turn up the volume level to a higher level after your sub modification than you did before it. Since the sub produces the type of sound most associated with the perception of loudness, my guess would be that for some reason your sub isn't as responsive as it was before. Your mentionning the fact that it's clipping rather than bottoming sorta leads me to this conclusion. This may be solvable with a phase adjustment or experimenting with different sub placement. Very low frequencies are the ones most associated with our perception of loudness, and also are subject to some weird standing wave effects and such.

    You're basing your concerns on perceived volume levels rather than measured levels, which makes it kinda hard to verify anything, just for giggles maybe you're just getting used to higher volume levels and your own perceptions of what's loud are changing? without meter readings this scenario is not beyond the realm of possibility.

    If your MCACC settings and perceived volume levels have been reasonably consistent since the sub mod, I find it difficult to blame this on the receiver.

    The only way to verify anything reliably would be to record what spl meter readings are now at a given volume setting from each speaker's test tones, rerun MCACC and re-measure spl meter readings after undoing whatever mod you did to your sub.

    If you can produce uncomfortably loud sound at a volume setting of 0 db or lower and have no shutdown problems, I don't see where you have anything to worry about. It may be a simple thing--perhaps before the sub mod you had your speakers set to small and now they're large, or vice versa. If you don't remember what these settings were before the sub mod, there's no way to reliably evaluate this situation.

    Even some dvds are recorded at different levels, the original release of LOTR was uncomfortably loud at -17db on my reciever, while most all other discs are about right, by my perception of loudness. I had to turn it down to -27db before it sounded about the same as my other movies.

    Whatever the cause of this apparent discrepancy, I really don't think there's anything to worry about.
     
  3. Steve Vinson

    Steve Vinson Auditioning

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    Steve,

    Thanks for the suggestions. I will test the volume levels with my SPL meter. I'm also wondering about the possibility of phase cancellation.

    Steve V.
     
  4. Steve Schaffer

    Steve Schaffer Producer

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    Phase cancellation and other issues relating to the standing wave characteristics of Subs can be a real problem.

    I was experimenting with sub placement using the low frequency sweep on AVIA and the sound meter. My goal was to achieve the flattest possible response through the entire range of the sweep.

    Unfortunately I found the flattest response occured with the sub located in the dining area adjacent to the family room, roughly under the dining table!

    In this one case I had to compromise performance to asthetics, something I rarely have to do as I have no WAF to deal with.

    Gee this hobby is fun!
     
  5. MikeRP

    MikeRP Supporting Actor

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    The sub thing is really interesting. I recently changed my home theater to a new room in the house.

    In the old room - I had all kind of sub problems. Volume too loud in some places and too low in others.

    So, I was careful on the new room and did a lot of research before I set the room up (still alot of compromises). I was considering replacing my Def Tech Pro 100 before but now I have too much sub and bass. THing is this room is more like a square and it has good bass and sub volume seemingly everywhere. I consider that luck. So, my sub upgrade is off. I'm fine and I'll do it in a year or so.

    As far as your readings they seem very high. Everything weighted to the plus side. How big is your room?

    Make sure the furnace is off when you run the MCACC is a suggestion - needs to be as quiet as possible. I even turn off the fridge and no one is at home when I do it.

    Again, I'm suprised those readings are so heavy to the plus side.

    Nice thoughtful post Steve S.!

    Mike
     
  6. Scott_Jua

    Scott_Jua Stunt Coordinator

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    I've done the MCACC on mine a few times already, but for the first two times I took more precautions about how my room was souding with ambient noise and such.

    The most recent time I did not bother to turn off the fish tank, the thermostat or anything else creating noise. I figured that since I want to watch movies and listen to music with those things on normally anyway...shouldn't I then leave them on for the MCACC to calibrate around???

    That way the 45tx can take those noises into account and calibrate aroudn them to compensate for the noise the they make...???

    hmmmmmm
     
  7. MikeRP

    MikeRP Supporting Actor

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    Intersting thought Scott.............hmmmmmm....we ought to do some testing to see the differences.

    Good Thought![​IMG]

    Mike
     

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