Ballpark Driver requirements

[hotshoetom]

Hi Guys,

I have a 3900 cu. ft. room that I would like to be able to get 115 db @ 10 Hz. Can anyone tell me how to go about calculating what I will need driver-wise and amplifier-wise to achieve that goal? I am assuming that I will be using a similar size adjacent room to the HT room in my basement as the 'enclosure' for an IB type setup.

I have a pair of the 'original' smaller Hsu tube subs they were selling 10 years ago and they are pretty much shot. In addition I have a pair of 12" car subs in a box + two more in cardboard boxes that need to have the surrounds replaced. Can anyone recommend someone to do the repair to those speakers? The current setup works ok above 30 Hz, but I'd really like to get some more extension and SPL too. The amp I am using is an old Adcom 555 II making 325/ch into 4 ohms.

Cheers!

Hotshoetom

[brent_s]

Download WinISD Pro Alpha or Unibox if you have Excel. Input the necesary T/S parameters for the drivers under consideration. Model a sealed enclosure with the larget volume the program will allow...or the actual volume of the room you're considering for your IB. Input the power you will have available and look at the SPL graphs. WinISD will let you specify the number of drivers in the model, can't remember about Unibox. Both simulate groundplane numbers so you can probably safely add +6dB or so to the numbers you see...varies by room size, construction, and speaker placement within the room. I get +10dB @ 20hz in my 24x16x9 dedicated theater room.

-Brent

[brent_s]

Quick model with four FiCarAudio IB18s with 1000 watts (250/driver) in 10,000 ft^3 (true IB) will get you 109dB @ 10hz at 1m groundplane. So, that should easily get you at least 115dB in room. The IB18's aren't on the FiCarAudio web site, but they're stickyed in the Shack's Fi forum. A four pack is $199/driver.

-Brent

[Avus_M3]

I've been playing with WinISD for awhile now and find it very easy to use. I do have a quick question though...on the advanced box options what should the QTC, QL, and QA read? QTC is locked because it's a closed box but what about the other 2? I emailed Scott and am awaiting his reply to order 4 Fi IB 18's for 29L's of displacement capability

[brent_s]

Avus_M3 wrote:

I've been playing with WinISD for awhile now and find it very easy to use. I do have a quick question though...on the advanced box options what should the QTC, QL, and QA read? QTC is locked because it's a closed box but what about the other 2? I emailed Scott and am awaiting his reply to order 4 Fi IB 18's for 29L's of displacement capability

I leave them on their default values. Their meanings are somewhat defined in the help file. There may be resources on the web that discuss them in more detail. I'm pretty sure the LDC addresses them as well. Among other things, you can change the values to simulate how much stuffing is in the box or how much air leakage the driver and/or box has.

-Brent

[collo]

There's a handy SPL calculator here