Recommend a subwoofer design for my application:

[cast55]

I am running an active cross three way stereo triamplified (six channel) system.

My bass cabinets are vented EBS3, each carrying one EVX-180B driven by one channel of a QSC PLX3102. These cabinets are nicely flat to 32 Hz, and do extend lower than that to some extent. I have disabled the 32 Hz "subsonic" filter on the QSC, and instead implemented a 48 dB/octave L-R active slope at 20 Hz to roll off the subsonics and prevent driver overexcursion - the natural roll-off of the driver is somewhat higher than this. So configured, I'm pretty happy with the way these cabinets sound for music and movies, however I am definitely missing something on the extreme low end, and I was hoping to augment this infrasonic-to-low-sonic range with an additional sub.

Ideally, I would like something that can keep up with my mains (which are well into 130+ dB), but which cover the bottom octaves only, crossed at 32 Hz on the upper end, and extending down to 16 Hz at minimum, and 8 Hz if at all feasible. The project will be DIY, and difficulty is not really an issue. My budget is not set in stone, but I am thinking about $1K for amplification and $800 - $1K for drivers/enclosure, maximum. Huge transmission lines are probably out because I only have 8' ceilings.

Suggestions?

[epa]

Originally Posted by cast55

I am running an active cross three way stereo triamplified (six channel) system.

My bass cabinets are vented EBS3, each carrying one EVX-180B driven by one channel of a QSC PLX3102. These cabinets are nicely flat to 32 Hz, and do extend lower than that to some extent. I have disabled the 32 Hz "subsonic" filter on the QSC, and instead implemented a 48 dB/octave L-R active slope at 20 Hz to roll off the subsonics and prevent driver overexcursion - the natural roll-off of the driver is somewhat higher than this. So configured, I'm pretty happy with the way these cabinets sound for music and movies, however I am definitely missing something on the extreme low end, and I was hoping to augment this infrasonic-to-low-sonic range with an additional sub.

Ideally, I would like something that can keep up with my mains (which are well into 130+ dB), but which cover the bottom octaves only, crossed at 32 Hz on the upper end, and extending down to 16 Hz at minimum, and 8 Hz if at all feasible. The project will be DIY, and difficulty is not really an issue. My budget is not set in stone, but I am thinking about $1K for amplification and $800 - $1K for drivers/enclosure, maximum. Huge transmission lines are probably out because I only have 8' ceilings.

Suggestions?

verry narrow band
@ what freq you x-over to the mids?
is it mayby possible to redesign the ev 18"?
tapped horn or tqtp should go lower ,130 db is a challenge.

[tb46]

How abut the Matterhorn? :-)

Regards,

[cast55]

Originally Posted by epa

verry narrow band
@ what freq you x-over to the mids?
is it mayby possible to redesign the ev 18"?
tapped horn or tqtp should go lower ,130 db is a challenge.

As it stands, I am crossing over to my mids (18Sound 10M600 on one channel each of QSC PLX1802) at 254 Hz, and then to my highs (JBL 2441 compression drivers on 2382A horns, on a QSC PLX1104) at 2kHz.

This actually measures and sounds decent in the room; however, I am using more EQ than I like to do this - I think I might add a midbass between the EVX-180B and the 10M600 at some point to clean things up a little. That is looking long-term, though. I would prefer to focus on the portion of the spectrum which is missing entirely, which is the infrasonic and low sub range. I designed my bass cabs specifically for the EVX180B, and for their intended purpose, they work perfectly. High SPL, low distortion, and decent extension for that driver; however, they were designed for music / sound reinforcement, and not for theater / synthesized low frequency effects which is the material I am trying to address with the new sub.

Although a LFE cabinet which could reproduce the same SPL as the existing system would be ideal, I suppose this is unnecessary in consideration of the fact that I would never exhibit movies etc. at maximum SPL. That sort of power I only rarely use for sound reinforcement of material for which that sort of thing is expected.

What is tqtp?

[epa]

Originally Posted by cast55

As it stands, I am crossing over to my mids (18Sound 10M600 on one channel each of QSC PLX1802) at 254 Hz, and then to my highs (JBL 2441 compression drivers on 2382A horns, on a QSC PLX1104) at 2kHz.

This actually measures and sounds decent in the room; however, I am using more EQ than I like to do this - I think I might add a midbass between the EVX-180B and the 10M600 at some point to clean things up a little. That is looking long-term, though. I would prefer to focus on the portion of the spectrum which is missing entirely, which is the infrasonic and low sub range. I designed my bass cabs specifically for the EVX180B, and for their intended purpose, they work perfectly. High SPL, low distortion, and decent extension for that driver; however, they were designed for music / sound reinforcement, and not for theater / synthesized low frequency effects which is the material I am trying to address with the new sub.

Although a LFE cabinet which could reproduce the same SPL as the existing system would be ideal, I suppose this is unnecessary in consideration of the fact that I would never exhibit movies etc. at maximum SPL. That sort of power I only rarely use for sound reinforcement of material for which that sort of thing is expected.

What is tqtp?

sorry its tqwtp tapped quarter wave tapered pipe

[epa]

something like this




bms 18 860
klik on the pic to enlarge,then klik bottem left to enlarge again

[tb46]

Hi epa,

These designs need very solid corners to give the SPL indicated, maybe 2 x pi would be more appropriate? Two boxes with dual JBL GTO1214 in a DTS-10 style enclosure will also get there, with corner loading.

Regards,

[epa]

Originally Posted by tb46

Hi epa,

These designs need very solid corners to give the SPL indicated, maybe 2 x pi would be more appropriate? Two boxes with dual JBL GTO1214 in a DTS-10 style enclosure will also get there, with corner loading.

Regards,

hi tb46
i propose of corner loading these anyway.
i was thinking of a single fold.
what do you mean by solid corners?
haven,t moddeled these jbl's yet

[tb46]

Hi epa,

A corner in a basement build from concrete would qualify as solid, wouldn't it? Whereas 3/8" plaster board on metal wall studs spaced on 24" centers wouldn't. In the sub 30Hz frequency range sound has a tendency to just go through walls, and the corner effect disappears, you might not even get to 1 x Pi. Measurements would tell, but I would recommend modelling in 2 x Pi.

As to the JBLs, they are inexpensive, and Petter Persson already has done the basic work:

http://www.diyaudio.com/forums/subwo...n-2x12-th.html

Merry Christmas!

Regards,

[epa]

Originally Posted by tb46

Hi epa,

A corner in a basement build from concrete would qualify as solid, wouldn't it? Whereas 3/8" plaster board on metal wall studs spaced on 24" centers wouldn't. In the sub 30Hz frequency range sound has a tendency to just go through walls, and the corner effect disappears, you might not even get to 1 x Pi. Measurements would tell, but I would recommend modelling in 2 x Pi.

As to the JBLs, they are inexpensive, and Petter Persson already has done the basic work:

http://www.diyaudio.com/forums/subwo...n-2x12-th.html

Merry Christmas!

Regards,

ah i see ,i tought you meant the corners in the horn
that project looks verry promissing,ill look in to it tomorrow
tnx