Domestic sub: car ones are odd
 

"Eiron" wrote in message
...
Car sub drivers are just like any other, they have T-S parameters.
But if I use the T-S numbers and feed in a small box it shouldn't sound
good.


I use a Sony XSL-121P5, which was very cheap in the Halfords sale,
as a sub for my satellite system.
According to WinISD, in a 65l reflex box it is flat to 30Hz,
-3dB at 24Hz and -12dB at 18Hz, so with room gain it will be flatter.
It's a reasonable compromise between bass-extension and WAF.


Small enclosures give a gentle rolloff from a high frequency which
roughly matches the room gain of the car (with the windows shut,
of course.) You don't need such a lot of power if you correctly
match the levels of sub and main speakers.

Oh dear. Just when I thought I was getting somewhere! What you've
both said is useful. It seems that there is an alternative to disguising
the enclosure as a cupboard or table! How do I go about choosing
an enclosure? I can't use the conventional equations. I must look
for the TS numbers for some of the car type drivers I might use.

Peter Scott

Domestic sub: car ones are odd
 

In article ,
Peter Scott wrote:
I must look for the TS numbers for some of the car type drivers I might
use.

I'd also be careful about power handling if it's a car unit. Their watts
appear to be about 1/3rd of 'ours'. ;-)

--
*When I'm not in my right mind, my left mind gets pretty crowded *

Dave Plowman London SW
To e-mail, change noise into sound.

Domestic sub: car ones are odd
 

"Peter Scott" wrote in message

"Wally" wrote in message news:EDZ1e.7308
At present its a dual coil and bi-amped from the two channels.

Do you mean there are two drivers? In separate enclosures, one
presumes?

Actually now I'm finding out more about sub design I realise how
strange are the ones that are used in cars. I'm using Weems
'Designing, Building ...' and some info from Eminence. Knocked up a
quick spreadsheet based on Keele's formulae. Upshot is to get cutoff
of
less than 40Hz I need one hell of an enclosure and at least a 15"
driver.

There's at least one hidden agenda item. Speakers playing in a room
pick up a 12 dB/octave bass boost commencing at a frequency that is
inversely related to the to the size of the room. For big rooms this
starts at very low frequencies and frankly isn't much help. With small
rooms, this starts at relatively high frequencies and can be a great
help.

Just guessing, but the probable intent was to have a bass roll-off
starting around 80 or 100 Hz, which would match pretty well with the
frequency where the bass boost due to the relatively small volume of a
car kicks in.

Anyone know where I can buy BassBox in the UK? I
am awaiting a reply about buying it direct from Harries in the
US but its easier if there's a UK dealer. Google didn't help.

http://www.mhsoft.nl/spk_calc.asp#sealed

http://www.pvconsultants.com/audio/eq/boxcircuit.htm

Domestic sub: car ones are odd
 

"Arny Krueger" wrote in message
...
"Peter Scott" wrote in message


Anyone know where I can buy BassBox in the UK? I
am awaiting a reply about buying it direct from Harries in the
US but its easier if there's a UK dealer. Google didn't help.

http://www.mhsoft.nl/spk_calc.asp#sealed

http://www.pvconsultants.com/audio/eq/boxcircuit.htm


You are a hero Arny. Thanks, these look great. Harries will only
send the Lite version the manual and with various functions
missing. Hopefully these will give the answers I need. Midnight
oil again!

Peter Scott