Mike's Project - Zaph's MTM 16 (modded)

[Mike C]

I've seen a fair bit about the Eros, and I'm somewhat tempted as I believe the Scanspeak 95 tweeter is a good one that should suit my tastes quite well.

However, I get the impression that one can do quite a bit better now at a similar cost, similar size (as the Eros is now a somewhat old design?).

Remember, I like 'natural' bass rather than a 'hifi' sounding bass (I have not put that very well .... start again).
The IPLs have a slightly light bass - some are surprised at that, but see comments about the Thor. It is however tuneful in that it plays the music's notes, not the speakers own notes; they start and stop well. I'm looking for this kind of thing rather than bass 'slam' or impact.

A speaker that's just outside my size limits but appears ideal in just about every other way is Zaph's MTM 'speaker 16', the tower reflex version. As far as I know, the good mid/bass drivers should give me the midrange and vocals I love to bits, esp with the SET. Any comments?
And the efficiency looks ideal. SET friendly? Anyone know?

However, here I'm struggling so advice would be appreciated.
(Yes, I should read more about speaker design and will do).
Say I took Zaph's design and made 2 changes; baffle say 8.5 ins wide instead of 9 ins, and make it 40 ins high instead of 44.

The narrower baffle will I guess upset the BSC. But the near wall positioning might compensate to some extent? Or not! Is this wishful thinking?

The smaller volume will alter the bass; but I have no idea how, or why it's designed to that volume (related to Vas I assume).
More specifically .... if I change the volume as above, and wish to get the kind of bass I try to describe, can it be made to work and how do I tune the port?
Phew!

Or do I give up and buy the Castles? :-)

[Dave Bullet]

Vas is one of the T/S parameters used to determine an appropriate enclosure volume for driver(s). If you do change the height and width dimensions - you can increase (or decrease) box depth so the volume (therefore port diameter/length) can be kept the same to not affect tuning.

Regarding varying baffle dimensions - 0.5 an inch probably won't change the BSC much (a 5% change in width). What might be affected more is the high frequency (tweeter) response. Try and keep the driver placement on the baffle the same as Zaph's design.

Why do you want to change the enclosure dimensions anyway?

Cheers,
David.

[Mike C]

Originally posted by Dave Bullet
Vas is one of the T/S parameters used to determine an appropriate enclosure volume for driver(s). If you do change the height and width dimensions - you can increase (or decrease) box depth so the volume (therefore port diameter/length) can be kept the same to not affect tuning.


Why do you want to change the enclosure dimensions anyway?

Cheers,
David.

Thanks Dave.
The reason is given in my 'background' post (which is no longer close to this post due to how this board works, my mistake!). It is for WAF of course .... Mrs C will be happier if the new speakers are no larger than the present ones.

Regarding the possible changes; I prefer not to increase the depth if I can get away with it. By 'get away with it' my objective is to get good bass quality, with depth between that of the sealed box design and ported box (preferably much closer to the ported of course). To put a figure to it, use the Castle 7i as a benchmark; I'm looking for lower than 47Hz.

OK, I need to read up on speaker design as I only know about TLs (and I'm no expert on those).