Have been reading this thread, do you want to design a basshorn or something? With rear chamber?

In terms of size, remember that you need a horn long enough to reach the desired Fc. Horn length primarily determines this and should be 1/4 wavelength of the lowest frequency to be used.

Mouth size should also be of reasonable area, if a basshorn, then corner loading will obviously reduce the size needed considerably (the room will form part of the flare). Use Hornresp to determine a suitable area.

Rear chamber can be vented or sealed - the system will act as a direct radiator somewhere below Fc. If you want to run your system so that direct radiator mode provides useful output then keep Fc well above Fb. If you do this, then response falls at 12db/oct below Fc until sensitivity becomes that of the driver in direct radiator mode. Below Fb, it will drop at 12db/oct again, or 24db/oct if a vented rear chamber. In particular this is a good idea if a short horn is used such as to keep size down, and this sounds like exactly what you wanted to do.

Of course, the better thing to do is to simply use a longer horn with Fc at the lowest frequency you want to reach, that way you gain the most benefits out of horn loading over your whole bandwidth. Then you can reactance annul it if you wish. Also remember that if you do the short horn + rear chamber, that excursion will jump up high in the direct radiator region as acoustic impedance gets lower, you loose out benefits of the horn in direct radiator mode. So you can get acoustic output to a lower frequency, but excursion-limited power handling goes down too, hence limiting total SPL. If space is a concern though, it is one way to extend low frequency response.

Adrian

• my mods

I have no idea what your trying to do - what is the brand and model of the driver your usigng? What bandwidth exactly do you want to cover? What size restrictions physically have you got which is moving you towards this direction of small horn + low tuned rear chamber?

Is your plan so far basically one of Wayne's folded horn designs, and your own rear chamber?

yeah i want to use a bigger vented volume with a smaller horn that will hopefully work right. I planed on building the recomended box, my big box nonmodded then i modded box.

I am look for bass for my living room mainly like 30-80 the box i am using now has nice lowes but mudding midbass. i mean my eq 32 hzs is cranked and the 62 is the full way down.

I put the numbers through for the RF2210 woofer and Hornresp tells me that this woofer is not suited to a horn at all.

As for the digital design 9512, there isn't enough parameters there to model its horn response. I did derive some of the missing parameters that were required, using an approximate value for Sd and something else, but they didn't model well out on a horn either.

Your best bet is a bass reflex box for both of 'em, and forget about the horn. The box's that Wayne suggested will work fine. For the RF, use the bigger of his suggestions if you want response to 30Hz. And for the DD sub, Wayne's described a number of cabinets which will get you to 30Hz so just follow those suggestions. You may also consider looking at dual chamber reflex boxes.

Adrian