How to determine if my RTi4's are blown?

louhamilton
louhamilton Posts: 209
edited May 2008 in Speakers
Okay, I recently upgraded my system to include a Denon 3808CI ,PS3, and SVS PB12-NSD.

After watching Hitman, I noticed the mids in the RTi4's are a little muddy today. Sort of scratchy and not tight. I used the Denon to calculate all settings. The only thing I changed was the x-over from 40Hz to 80Hz.

Not sure what else I can say about it except that I typically listen at -40 to -30, but I bumped up Hitman to -20 just to really "feel" the movie.
Post edited by louhamilton on
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  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited May 2008
    Lou,
    Wow - I'm surprised that you may have blown your RTI4s.

    The Denon 3808CI is rated the same as my Yamaha RX-V1800 (130watts/channel - but measured at 103watts/channel 5 channels driven).

    Not sure what -20 'translates' to in relation to output, though.

    Still, to drive a speaker to damage would mean overdriving the amp into distortion and causing heat/damage in the drivers.

    I've driven my RTI4s pretty hard and loud, but mostly for music. I guess that means less dynamics than movie effects - maybe that's the potential problem - a short BIG spike in spl/dynamics during the movie?

    Loudest I drove my RTI4s (just from the avr and before using the Carver M-1.0t) during a movie was "Fellowship of the Ring" the scene with the Balrog vs Gandalf....WAY loud! But the RTI4s sounded clean w/ no damage.

    Keep us posted....
    Erik

    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
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  • zingo
    zingo Posts: 11,258
    edited May 2008
    It's possible I guess that you damaged the speakers. Receivers clip easier than a dedicated amp, and thus can cause damage easier and at a lower volume. 40hz is way too low of an x-over settings for those speakers or most speakers, and moving that up was a good idea. Push lightly on the driver and see if you hear a scratching sound.

    Erik, -20 refers to 20 db below the reference volume on the receiver. It's harder to damage the RTi4 with your Carver than a receiver for the reasons stated above. A dedicated amp provides "clean" power so to speak.
    Jake
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  • louhamilton
    louhamilton Posts: 209
    edited May 2008
    UPDATE:

    It seems to be related to only music streamed through the PS3. I hooked up my D-Link DSM-320 with an optical cable and the music is night and day. I need to play around with the PS3 and see if there are any settings that can be changed.
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  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited May 2008
    Lou,
    Glad to read that the RTI4s are not blown! The PS3 does have some settings for "music" (sampling rate, decoding, and bit mapping) - hope you find the right settings.

    This may go off topic here, but would like to learn more.

    I kinda sorta maybe understand the reference db thingy, but dbs are not dbs - depends on the units.

    Check out the chart here at the bottom:
    http://www.allaboutcircuits.com/vol_3/chpt_1/6.html

    If I understand correctly, -40dbm (this is where I think I need clarification on the exact db units being inferred when using db to refer to *power*) is the same as 0.002 watts.

    And even if Lou 'bumped' up the volume to -20dbm - that is still less than 1 watt of power!

    Or, maybe the unit isn't dbm but something else like dbV or dbu or dbFS??
    http://www.sizes.com/units/decibel.htm

    Now my head hurts! ;)

    If someone has a good link to point me to so I can sort db vs power out - I'll be quiet and study :)

    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
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  • Ron Temple
    Ron Temple Posts: 3,212
    edited May 2008
    Dolby reference level is 85dbs average and allowing peaks of 20dbs in the main channels and 30dbs for LFE. If you calibrate your AVR/pre-pro to 85dbs @ - 0, then that's reference level. Most AVRs can't do it without clipping. It's all relative, my reference point is -15.

    Combo rig:

    Onkyo NR1007 pre-pro, Carver TFM 45(fronts), Carver TFM 35 (surrounds)
    SDA 1C, CS400i, SDA 2B
    PB13Ultra RO
    BW Silvers
    Oppo BDP-83SE
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