Hi folks
I’m new to posting new threads so pls excuse any errors I may generate.
My problem is that I have a home made 12 cubic foot enclosure (2 x 2 x 3 foot inside dimensions) that I made originally for a JBL 2245H sub that was designed using winISD Pro built with 1” MDF.
The box sounded absolutely great except for one problem the JBL 2245 is not a good driver for a home theater sub as it runs out of xmax too quickly below 20Hz, as the winISD states it can only support 18 watts at 10Hz. Too bad I didn’t appreciate this fact before I purchased the JBL.
I refused to add any type of filter to limit the power below 20Hz as this would have defeated the purpose of the big box that was meant to get these really low earth shaking frequencies.
So in an attempt to salvage the box I purchased a new Audiobahn AW1805Q sub at a reasonable price and popped it into the enclosure. This sub did not have the xmax limitation of the JBL however it’s not producing any real output bass, it seems to be misaligned!
I have two 4 inch vents on the enclosure (I know I should have more or bigger vents but that’s another issue best told later) where the winISD calls for 11.24 inch lengths for a 20Hz resonance and the AW1805Q calls for 11.24 inch vents so I figured that keeping the same vents should have little impact on the sound. Unfortunately, I can hardly get any deep base out of the system.
So seeing how the JBL is a really efficient driver but was limited to 300 RMS (being pushed by a 450 watt amp) the AudioBahn could handle 1200 watts (not sure if this is RMS or peak), so I purchased a Yamaha P7000 amp which is capable of producing 2200watts into 8ohms bridged (the Audiobahn has 2x 4ohm VC wired in series giving the same impedance as the JBL). But even with this amp the Audiobahn just isn’t putting anything decent out (my 12 inch woofer in my ESS monitors running off of 200 watts is putting this sub to shame!). I’ve tested the driver and it seems fine, both VC’s read 3.3 ohms and the cone moves without any friction although its compliance is very stiff (compared to the JBL). The cone does move properly when driven but there’s not much sound output, thus the misalignment theory seems to be the only possible cause.
From this I question whether the winISD is giving the correct information can anybody out there test what an Audiobahn AW1805Q should do in a 12 cf vented enclosure and compare it to winISD?
The winISD TS parameters for the Audiobahn are:
QES 0.440
QMS 5.270
QTS 0.406
FS 23.20 Hz
VAS 4.697 ft^3
Mms 607.3
Cms 0.775 mm/N
Rms 16.79920 N c/m
Re 3.3 ohms
BL 25.76798 N/A
Dd 14.73 in
Le 2.85 mH
Sd 0.1100 m^2
Xmax 26mm peak
Vd 2860 cm^3
Pe 1200 w
No 0.3671
Znom 4.000
USPL 91.65
SPL 87.80
Voicecoils 1
Connection Parallel
Note I had lots of problems getting the winISD to accept the TS parameters for this driver unless I fudged the number of voice coils and set the connection to parallel, and I believe this may have affected the vent length calculations.
Thanks
Philip
I’m new to posting new threads so pls excuse any errors I may generate.
My problem is that I have a home made 12 cubic foot enclosure (2 x 2 x 3 foot inside dimensions) that I made originally for a JBL 2245H sub that was designed using winISD Pro built with 1” MDF.
The box sounded absolutely great except for one problem the JBL 2245 is not a good driver for a home theater sub as it runs out of xmax too quickly below 20Hz, as the winISD states it can only support 18 watts at 10Hz. Too bad I didn’t appreciate this fact before I purchased the JBL.
I refused to add any type of filter to limit the power below 20Hz as this would have defeated the purpose of the big box that was meant to get these really low earth shaking frequencies.
So in an attempt to salvage the box I purchased a new Audiobahn AW1805Q sub at a reasonable price and popped it into the enclosure. This sub did not have the xmax limitation of the JBL however it’s not producing any real output bass, it seems to be misaligned!
I have two 4 inch vents on the enclosure (I know I should have more or bigger vents but that’s another issue best told later) where the winISD calls for 11.24 inch lengths for a 20Hz resonance and the AW1805Q calls for 11.24 inch vents so I figured that keeping the same vents should have little impact on the sound. Unfortunately, I can hardly get any deep base out of the system.
So seeing how the JBL is a really efficient driver but was limited to 300 RMS (being pushed by a 450 watt amp) the AudioBahn could handle 1200 watts (not sure if this is RMS or peak), so I purchased a Yamaha P7000 amp which is capable of producing 2200watts into 8ohms bridged (the Audiobahn has 2x 4ohm VC wired in series giving the same impedance as the JBL). But even with this amp the Audiobahn just isn’t putting anything decent out (my 12 inch woofer in my ESS monitors running off of 200 watts is putting this sub to shame!). I’ve tested the driver and it seems fine, both VC’s read 3.3 ohms and the cone moves without any friction although its compliance is very stiff (compared to the JBL). The cone does move properly when driven but there’s not much sound output, thus the misalignment theory seems to be the only possible cause.
From this I question whether the winISD is giving the correct information can anybody out there test what an Audiobahn AW1805Q should do in a 12 cf vented enclosure and compare it to winISD?
The winISD TS parameters for the Audiobahn are:
QES 0.440
QMS 5.270
QTS 0.406
FS 23.20 Hz
VAS 4.697 ft^3
Mms 607.3
Cms 0.775 mm/N
Rms 16.79920 N c/m
Re 3.3 ohms
BL 25.76798 N/A
Dd 14.73 in
Le 2.85 mH
Sd 0.1100 m^2
Xmax 26mm peak
Vd 2860 cm^3
Pe 1200 w
No 0.3671
Znom 4.000
USPL 91.65
SPL 87.80
Voicecoils 1
Connection Parallel
Note I had lots of problems getting the winISD to accept the TS parameters for this driver unless I fudged the number of voice coils and set the connection to parallel, and I believe this may have affected the vent length calculations.
Thanks
Philip