I posted this experiment in the Home Theater section but no comments so I thought I would try here. This is where the guys with some technical know-how hang out.
I have a popping problem with my REL Strata 5 Sub - 10inch driver, 150w amplifier, downward firing, sealed box of modest size (don't know how many litres)
The experiment
Sound meter Bruel & Kjaer type 2250 (ie top quality professional model)
Test tracks
Ani Difranco "I know this Bar" (acoustic guitar, piano and slow kick drum)
Sonic Animation "love lies bleeding" & "I'm Afraid I think I'm human" (electronic)
Background levels in my lounge room
average 22db (35db at 12.5hz distant traffic or fridge)
Methodology - set up sub with high level connection. location - against rear wall, room 3.5 by 6.5m, timber construction, carpet, sub sitting on dense concrete paver - then disconnected main speakers so that only the sub played. Measurements taken from the seating position about 2.5m from the sub - as far as I could tell this was not in a node or anti node (there is definitely a node about 1.5m to my right in line with the open corridor)
Results
"I know this bar" - well this was an interesting track. The display on this meter shows volume over the frequency spectrum - like those flashy displays on a graphic equaliser. The display showed that the sub was playing at 65db from over just below 63 hz all the way down to 12.5 hz. I don't think a Strata 5 actually goes that low so I suspect the whole sub was resonating - and of course the pops were present. I have a quicktime movie of the meter - unfortunately the bass sound is nothing more than a click as it was beyond my digital cameras capabilities. File is too big to post - sorry.
Ehen the volume was turned down so that some of the "kick drum" hits were not popping the line is still almost flat below 63hz down to 12.5hz. This is interesting as people who know music will tell you there is rarely anything below 30hz and a kick drum does not go down this low (the drum sounds like it has been distorted or something- might even be electronic).
Next some dance "doof" music by Sonic Animation.
This read very differently. big peak at 63 hz then a big drop off either side. (This is curious as the subs filter was set at 38 hz - obviously it is not a brick wall filter - it did make me wonder again about room nodes)
I got peaks of 90db @ 63hz - the house rattled but the sub was still holding on. This is typical for dance music as I have seen similar readings on this meter outside dance clubs - ie the big peak centered around 63hz.
Conclusions - well the sub did ok with movies (previous test) and dance music but it just did not like that Ani Difranco track. It would appear to be an unusual track however a friends Rel Brittania 3 played the track at high volumes with no problems - the Strata 5 stuggled and failed.
Design limitations or a fault - well only an expert sub designer could tell me (thats you guys). Rel have never once replied to my repeated requests for advice and the importer in Australia after testing the sub initially only gave me three words "Its working fine" but have since said they would check with REL - no answer since that time.
The local REL dealer has offered to look at it so when I get the time I will drop it in for a checkup.
Any comments, suggestions or advice (apart from I should have made my own sub)
Thanks in advance !
I have a popping problem with my REL Strata 5 Sub - 10inch driver, 150w amplifier, downward firing, sealed box of modest size (don't know how many litres)
The experiment
Sound meter Bruel & Kjaer type 2250 (ie top quality professional model)
Test tracks
Ani Difranco "I know this Bar" (acoustic guitar, piano and slow kick drum)
Sonic Animation "love lies bleeding" & "I'm Afraid I think I'm human" (electronic)
Background levels in my lounge room
average 22db (35db at 12.5hz distant traffic or fridge)
Methodology - set up sub with high level connection. location - against rear wall, room 3.5 by 6.5m, timber construction, carpet, sub sitting on dense concrete paver - then disconnected main speakers so that only the sub played. Measurements taken from the seating position about 2.5m from the sub - as far as I could tell this was not in a node or anti node (there is definitely a node about 1.5m to my right in line with the open corridor)
Results
"I know this bar" - well this was an interesting track. The display on this meter shows volume over the frequency spectrum - like those flashy displays on a graphic equaliser. The display showed that the sub was playing at 65db from over just below 63 hz all the way down to 12.5 hz. I don't think a Strata 5 actually goes that low so I suspect the whole sub was resonating - and of course the pops were present. I have a quicktime movie of the meter - unfortunately the bass sound is nothing more than a click as it was beyond my digital cameras capabilities. File is too big to post - sorry.
Ehen the volume was turned down so that some of the "kick drum" hits were not popping the line is still almost flat below 63hz down to 12.5hz. This is interesting as people who know music will tell you there is rarely anything below 30hz and a kick drum does not go down this low (the drum sounds like it has been distorted or something- might even be electronic).
Next some dance "doof" music by Sonic Animation.
This read very differently. big peak at 63 hz then a big drop off either side. (This is curious as the subs filter was set at 38 hz - obviously it is not a brick wall filter - it did make me wonder again about room nodes)
I got peaks of 90db @ 63hz - the house rattled but the sub was still holding on. This is typical for dance music as I have seen similar readings on this meter outside dance clubs - ie the big peak centered around 63hz.
Conclusions - well the sub did ok with movies (previous test) and dance music but it just did not like that Ani Difranco track. It would appear to be an unusual track however a friends Rel Brittania 3 played the track at high volumes with no problems - the Strata 5 stuggled and failed.
Design limitations or a fault - well only an expert sub designer could tell me (thats you guys). Rel have never once replied to my repeated requests for advice and the importer in Australia after testing the sub initially only gave me three words "Its working fine" but have since said they would check with REL - no answer since that time.
The local REL dealer has offered to look at it so when I get the time I will drop it in for a checkup.
Any comments, suggestions or advice (apart from I should have made my own sub)
Thanks in advance !
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