Bass for my soldier

[Nathenry]

34hz is prefect and the size 200l is also fine.
so is the higher tunning the best togo with?
Thanks

[sreten]

Originally Posted by Nathenry

34hz is prefect and the size 200l is also fine.
so is the higher tunning the best togo with?
Thanks

Hi,

The higher tuning is best if your only subsonic filter option is non peaking,
and that should be set to around 30Hz, 2nd or 3rd order Butterworth
are the usual options, both only need one op-amp, and must be used
to approach anywhere near the bass ends maximum capability.

Not always, a lot of recordings have little bass below 40Hz, but if
one comes along that does you would be in trouble. If the sound
source is a PC then plugin bass filters are a very viable option.

The lower tuning + mildly peaking filter is better, sound quality wise but the
extra bass extension lowers the maximum SPL as extra bass always does.

The recommended box and tuning is hard to argue with, especially outdoors.

rgds, sreten.

[Nathenry]

i will go with the higher tuning
The recommended box and tuning is hard to argue with, especially outdoors.

[tb46]

Hi Nathenry,

I generally agree with sreten's comments on tuning and filtering, it may be important, to point out, that he is referring to the box recommended in the factory data sheet, not the B&C SUB18 as recommended earlier in this thread. As to filters, it is my opinion, that a bass reflex enclosure should not be used in high power applications (i.e.: PA or block parties) without a suitable low cut (high pass) filter; when the low frequency content of the music drifts below the tuning frequency of the enclosure, the excursion of the driver will become excessive...

The 18TBX100 data sheet shows an example of a BR enclosure w/ a volume of 200 L and a tuning frequency of 34 Hz. It uses a port with an area of 339.6 cm^2 and a length of 26 cm.

The previously recommended factory B&C SUB18 (Post #9) is 183 L and tuned to 35 Hz. It uses a split slot port with an area of 541.2 cm^2 and a length of 32 cm.

I want(ed) to point out, that you can reduce the internal volume even more without any negative effects. I'll attach another Hornresp Wizard screenprint, this time I shortened the port(s) to 25.40 cm (10"). You can see the effect on the frequency response, and the tuning frequency (bottom right: Helmholtz freq is 39.53Hz). In other words, you can tune either one of these boxes high or low. I also tried to make this box as easy to build as possible.

I'll also attach a Rev. A of the drawing:

Regards,

[Nathenry]

Oliver thanks for the update drawing.

[Nathenry]

Ok more info coming in. the speakers my husband used above his bass speakers is one of Bill fitzmaurice DR's top.

[sreten]

Hi,

183L tuned to 35Hz will work fine, not a lot in it versus 200L/34Hz.

rgds, sreten.

[Nathenry]

Originally Posted by sreten

Hi,

183L tuned to 35Hz will work fine, not a lot in it versus 200L/34Hz.

rgds, sreten.

Ok

[ODougbo]

Question for the pros (woodworker guy here) are you saying not to build a bigger box to lower the bass - to increase the SP/output?

[sreten]

Originally Posted by ODougbo

Question for the pros (woodworker guy here) are you saying not
to build a bigger box to lower the bass - to increase the SP/output?

Hi,

If you restrict the bass output of a PA cabinet it will generally handle
more power and go louder in the bass range it covers. As said you
need a high pass filter. Some high output high power handling bass
PA cabinets are very surprisingly restricted in real bass response.

e.g. This 1 x 18" :



Allegedly does 136dB, but
"Frequency Range loud (-10 dB) 50Hz -142 Hz".
"Frequency Range deep (-10 dB) 45Hz -138 Hz".

-10dB at 50Hz and 45Hz is no great shakes by anybodies standards.

rgds, sreten.