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New member Username: ToobsessedwithbassPost Number: 1 Registered: Mar-09 | I recently purchased the Rivals test tones cd and Radio shack audio meter to eq my system. I was surprised to see my Magnepan MG12s rolled off after about 12k and produced nothing audible at 16k. I have a really open family room and my Maggies are more than 3 feet out from the walls. I checked by changing to the Onkyo 805ss primary outputs rather than my old crown DC 300s,that normally power them, and even switched to my older Yamaha receiver with the same results. I tried the disc on my old Sony Walkman and could here the tones from the headphones. Maggie specs indicate they are flat to 23k. Am i missing something? By the way, I tried my Sony Blu ray 550s and on older sony DVD with the same results |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 13402 Registered: May-04 | . The manufacturer's spec is taken in a semi-anechoic environment. What you saw with the RS meter is weighted in a different manner which will allow for quite a bit of deviation in the numbers, particularly when measuring something other than a monopole speaker system. Additionally a real room measures unlike an anechoic chamber. Actual in-room response probably should drop off rather quickly between 12-16kHz in most rooms when measured with the RS meter. Quite a bit will also depend on the microphone position relative to the high frequency driver of the panels when using the RS meter. If the speakers sound balanced to your ears, then I wouldn't be concerned about the deviation indicated by the RS meter. . |
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New member Username: ToobsessedwithbassPost Number: 2 Registered: Mar-09 | Thanks for your response. I notice a drop off on percussion compared to my old M&K 1As and my RHS surrounds, but they are still very clear. I was concerned that the Crown DC300MK2 might not have been clen enough but it seems to be as clear as the Onkyo, but with more headroom. My room is 35X25, opening into a kitchen area. I am using 2 Alpine 1242d, in a cabinet tuned to 25 hz. The meter shows a strong peak at 40hz, but flat to -2-3 db at 25hz. My ears tell me not enought bass at 25-35. Is there a benefit to adding 2 more subs due to the large sqft. By the way, my ceiling height is 14 ft. |
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New member Username: ToobsessedwithbassPost Number: 3 Registered: Mar-09 | By the way, I am using the C weighting according to Rivals instructions |
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Bronze Member Username: ChrisgwdCalifornia Post Number: 35 Registered: Aug-06 | Rob, The RS SPL also has a pretty good roll off up in that region. Did you take into account the cal curve? See here for a graphical curve: http://www.realtraps.com/art_microphones.htm And here for a cal correction file: http://www.hometheatershack.com/forums/downloads-area/19-downloads-page.html By the way, your room sounds very similar to mine. I am also in the process of trying to figure out how to measure it and set it up properly. My RS SPL is out for cal and I have not really measure my room yet. I just put a pair of new monitors and a pair of 12" subs from Selah Audio and haven't gotten them tweaked up yet. I had a single M&K V2B sub prior to that. It would shake the room, but it wasn't as clean as I'd like and I think the room modes drove a bit towards a one note resonance. Good Luck! Chris |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 13403 Registered: May-04 | . Measurements taken beneath 300-500Hz in a room meant for living and not testing cannot be trusted since there can be as much as 20dB variance from flat response indicated by the meter. IMO the RS meter worth is its price only between approximately 1- 5kHz. That amount of accuracy would depend on the room set up and the skills of the user. This would be fine for basic level setting in a HT system but not much else. Otherwise take any numbers provided by the RS meter as a guideline at best. . |
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Bronze Member Username: ChrisgwdCalifornia Post Number: 37 Registered: Aug-06 | Thanks Jan, I should have noted that it is stated somewhere in that review of the various Mics and SPLs that the RS SPLs, unit to unit, are pretty consistent below 5k and the general cal curve can be pretty good. Above that, they vary from unit to unit and applying the general cal curve doesn't really work. Chris |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 3213 Registered: May-05 | Interesting points, however I feel the need to interject... Rives knows the RS meter very well. They describe it as not very accurate, yet very consistant. They therefore made a set of test tones on the CD for use with the RS meter. I have no idea what they corrected for nor how they did it. Rives is a very well respected acoustics company. I'd trust that the specific tones used as they were intended with a RS meter will be very accurate. Maybe not professional in-home service accurate, but probably more accurate than any other DIY measurements. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 13404 Registered: May-04 | . Sounds like it's time to call Rives and ask a few questions. |