Bruno_du_13
12-21-2015, 07:32 AM
Hello,
I use a 3-way triamp'ed system built of a 18" 2268H, a CMCD-81H (8" 2169H driver) and a 2452H 1.5" driver loaded by a 40° PT Horn
This is almost the same drivers of the SRX738 (link below) excepted for the HF PT driver, which was at first a 2431H, replaced by the 2452H.
http://www.jblpro.com/ProductAttachments/JBL_SRX738.v1.pdf
Cut-off frequencies are 350Hz and 2KHz, active, 24dB/oct slopes, with parametric EQ to make the response almost flat using a XTA digital active crossover.
-> So the 1.5" 2452H is used between 2kHz and 20KHz.
The size of the PT horn is about 10" X 5".
The natural measured frequency response of the 2452H with the PT horn is extended below 2kHz.
Problem:
At rather high sound level (at home, let's say above 100dB/1m), it becomes a little agressive in the mid frequencies. CMCD 8" exhibits very little distortion and should not be the problem. Furthermore, its unsmooth response above 2kHz is strongly filtered (24dB/oct slope + EQ attenuations)
Hearing close to the loudspeakers, it seems indeed this is the 2452 who sounds harsh.
So here are my questions :
. what is the lowest recommanded frequency cut-off for a 2452H with such of horn ?
. Is there some distorsion problems with the 2452H used above 2kHz?
. if 2kHz is too low for that 1.5" / PT association, should a D2 driver (the HF section of the JBL M2) be the solution? in the M2 the cut-off is 800Hz, but the horn area is a lot higher than the PT one.
I note M2 HF horn is not usable for my system since its dispersion is 120° width, against 60° for the PT horn (and also the 8" CMCD).
Thanks in advance,
Regards
Bruno
I use a 3-way triamp'ed system built of a 18" 2268H, a CMCD-81H (8" 2169H driver) and a 2452H 1.5" driver loaded by a 40° PT Horn
This is almost the same drivers of the SRX738 (link below) excepted for the HF PT driver, which was at first a 2431H, replaced by the 2452H.
http://www.jblpro.com/ProductAttachments/JBL_SRX738.v1.pdf
Cut-off frequencies are 350Hz and 2KHz, active, 24dB/oct slopes, with parametric EQ to make the response almost flat using a XTA digital active crossover.
-> So the 1.5" 2452H is used between 2kHz and 20KHz.
The size of the PT horn is about 10" X 5".
The natural measured frequency response of the 2452H with the PT horn is extended below 2kHz.
Problem:
At rather high sound level (at home, let's say above 100dB/1m), it becomes a little agressive in the mid frequencies. CMCD 8" exhibits very little distortion and should not be the problem. Furthermore, its unsmooth response above 2kHz is strongly filtered (24dB/oct slope + EQ attenuations)
Hearing close to the loudspeakers, it seems indeed this is the 2452 who sounds harsh.
So here are my questions :
. what is the lowest recommanded frequency cut-off for a 2452H with such of horn ?
. Is there some distorsion problems with the 2452H used above 2kHz?
. if 2kHz is too low for that 1.5" / PT association, should a D2 driver (the HF section of the JBL M2) be the solution? in the M2 the cut-off is 800Hz, but the horn area is a lot higher than the PT one.
I note M2 HF horn is not usable for my system since its dispersion is 120° width, against 60° for the PT horn (and also the 8" CMCD).
Thanks in advance,
Regards
Bruno