First home speaker project, need measurements.

[HiggityHank]

Hey all,

After waiting and waiting to install my much nicer components in my car, I've decided I don't really need them there. (nor do I really want to do the custom fiberglass etc.) So I've got this really nice set of components with a Madisound XO, and all they need is an enclosure.

I've got the following:

Peerless CSX 176H
Morel MDT 39
Madisound Crossovers

And using WinISD I've come up with an enclosure with interior measurements netting 10"x18"x13" (1.4 cubic feet, 34.2l) with a 3" port 10.25" long setting the tuning at 35.6Hz. Does this sound right to everyone? (I have tacked a bit onto the total volume to make up for driver displacement, XO displacement, and bracing. WinISD's measurement was exactly 1.207 ft^3)

[Timn8ter]

I'm curious as to the construction of the XO. Was it designed for those specific drivers?

[sreten]

All i'll say on this is assuming the Madisound croosovers are
correct for in car use they will not compensate for 'Baffle step
diffraction' loss which occurs in free standing loudspeakers
and the bass will be shelved down.

Alternatively the XO you've bought is designed for domestic
loudspeakers (and should have never be used in car) so
as long as you stick to a sensible baffle width it will be fine.

With Vas = 28 litres you start chasing your tail going beyond
this for box volume, your parameters sound fine, but TBH you
wont lose much going to 25/30 litres and 35hz.

/sreten.

[Timn8ter]

Even if it was intended for those drivers and home use isn't the impedance of the driver affected by the enclosure to some extent?

[sreten]

Not at frequencies relevant to the crossover /sreten.

[HiggityHank]

the XO was designed for use with these drivers.

So what you're saying, sreten, is that I'm overbuilding? (too large?) Could you suggest some alternatve measurements?

[sreten]

35 litres isn't overdoing it unless a major concern is cabinet size.

The crossover should be designed for the specific drive units
for domestic use and for a specific cabinet width - which you
should be able to get from Madisound.

Given the cabinet width which is usually around 9 inches total,
the other two exterior measurements are not critical.

If size is an issue then I'd recommend 25 litres tuned to 35Hz.
Still quite a big cabinet for a 6.5 incher.

/sreten.

[rabbitz]

Have a look at the Peerless data sheet which has recommended volumes and tuning.
http://www.wescomponents.com/peerless/850122.pdf

Used 30 litres on mine. Try tuning the port at several frequencies. I ended up with 44Hz, appears to be too high, but it just happened to sound better in my room with my equipment and probably due to a bit of a peak between 50-70Hz.