jbl 2225h need box calc

[djk]

This box looks pretty good for a pair of JBL 2225H. It's an EQ'd 6th order design, tuned to 31hz. The general layout is:



Here is the performance with the original driver I designed it for:



It is 100.4dB/2V/1M (1W), 128.2dB at full power (600W). 3dB down at about 29hz. The JBL driver has about 2.3dB less maximum output in the 50hz~60hz region due to its higher Fs and its lower Vas and x-max.

[tomp787]

Here is some simulation data based on the box dimensions. It was done by Zilch and posted on Audioheritage.

[mastadon]

what driver did you design those boxes for ???

Originally Posted by djk

This box looks pretty good for a pair of JBL 2225H. It's an EQ'd 6th order design, tuned to 31hz. The general layout is:



Here is the performance with the original driver I designed it for:



It is 100.4dB/2V/1M (1W), 128.2dB at full power (600W). 3dB down at about 29hz. The JBL driver has about 2.3dB less maximum output in the 50hz~60hz region due to its higher Fs and its lower Vas and x-max.

[djk]

I had a driver custom made for them, the part number Eminence assigned the design was 15711.

The simulation is of another custom Eminence driver, sold by Martinsoundpro.com. Their part number is #1844.

It is also possible to use some 18" drivers in this design, it just depends on the T/S parameters.

Of course the size may be adjusted for almost any driver with a Qts around 0.312, the cut-off will be around Fs, and the size about 0.41x the Vas.

[mastadon]

it may appear, you are correct, i just downloaded a real time analyzer, (Software) it has a tone generator and oscillascope, anyways i was using the tone generator, and listening to 30hz and i didnt realize how low that was. my yamaha 10
' subs were chuffin and not liking be called upon to reproduce that

Originally Posted by Brett

I agree with Ron for a couple of reasons. First of all he is correct re our brains filling in the fundamentals. Next, go and measure some: even on a 34" scale 4 string the fundamental on most low E is much lower than the 2H. On a B it is even worse as the strings aren't long enough to support it.

Have you ever had 30Hz loud on stage (presume you want this for at least some live work)? It's very annoying and can cause all sorts of resonances and muddy the sound.

Also consider many of the popular BG rigs such as Ampeg 4 and 8x10 dive below 70Hz and yet are often described as having good fundamental tone. For recording direct with maybe some micced cab mixed usually in sounds best.

[Robert2k]

I'm planning to build copy of JBL 4685 with 2 x JBL 2225h, please help about enclosure design.

[epa]

FYI
low B (B0)is 30.87 hz .
on the left a sine wave 31 hz,on the right a snapshot of music with 31 hz bas(see the harmonics )