Phil Allison wrote:
Jim Lesurf wrote:


The real problems with digital 'EQ' for room and speaker are more
complicated. It depends on the details of what you need to 'correct'. The
most obvious example being a room or speaker response that has a narrow and
deep dip somewhere.

And some room/speaker problems are almost unfixable by such means as
"measure the frequency response, then 'invert it' to get a flat result".



When the DiAppolito MTM configuration was first thought up, the odd or even
order crossover was selected to provide maximum range of dispersion. His
was vertically mounted. Then decided it was better to narrow dispersion by
changing order of crossover, to minimize ceiling floor bounces. I always
went for maximum dispersion, especially in horizontal mounting. I like to
move around a bit. The drivers natural phase change must be entered in the
crossover order, at selected crossover frequency.

Greg

** Best thing you can do is to EQ the speakers themselves outdoors in the
back garden. Suggest you put the pair side by side and the test mic in
the central position, about 2 metres away.

( If you have Quad ESL63s or the like, just forget it, you cannot improve perfection)

Nothing an EQ can do will fix a poor listen room but human ears do learn
to listen through some of the defects in a room given time - but a
reverberant room is a dead loss from the outset. Means a typical room
with bare walls & ceilings,large glass windows etc. Polished wood floors
are an abomination, sound wise.


FYI:

Best listening room I or anyone I know ever experienced belonged to a
friend of mine living nearby in Sydney. Prompted by suggestions from
myself and some telephone advice from an acoustics expert - his 5m x 10m
x 3m lounge room was as follows.

1. Timber floor over joists, covered in shag pile carpet and underlay =
dead to low, mid and high frequencies.

2. Double brick cavity walls covered in short pile carpet from floor to
ceiling on 3 sides, bookshelves full of books on the fourth = dead to mid
and high frequencies.

3. Large timber frame covered in carpet and underlay strung 0.3m under
the plaster on joist ceiling covering about 50% of the area - hung above
the listening position.

4. Heavy curtains covering the two small windows.

5. Listening position was 4 metres away from the rear wall and speakers
about 3 metres in front of that.

6. House in a quiet cul-de-sac with tolerant neighbours.

Result was nearly anechoic, anyone who spoke facing away from the
listener was hard to hear. Hand claps made *no* audible echo.

The room had stacked Quad ESL57s and a twin KEF B139 sub - parked against the rear wall.

Good recording sounded *spectacular*, with a clarity and the full
original ambience you only usually get to hear with electrostatic headphones.

In that room, I was able to also audition Yamaha NS1000s and
Magnaplaners, not at the same time though.

The Yamahas sounded remarkably similar to one pair of ESL57s but could
not beat two pairs when played loud. The Quad's sound was then very noticeably cleaner.

The Magnaplanars sounded just awful, poor sales dude who brought them
over for a demo that evening was reluctant to bring them inside after few
minutes spent listening to the stacked Quads.

My friend spent about the same money improving his room as he had on one
pair of Quad ESL57s - about $1000 in 1979. His only new purchase after
what was a Sony CD player in 1983 - after he had a good listening session
with my CDP101 of course.

The idiotic notion that the CD format was a lemon was rife in those days.


... Phil