On Thu, 24 Feb 2005 04:26:07 GMT, Joseph Oberlander
wrote:

different design. Now, I would think that mounting small Maggies
perpendicular to the side walls as satellites would be cool, since
dipoles seem to work well as satellites. Of course, it would look a
little weird, plus you might have to tinker with the angle and not
have them 90 degrees from the wall.

You'll get used to them quickly. They make them with off-white
fabric. I would mount them so that the edges are directly facing
your listening position(slightly off of 90 degrees from the wall)

If I didn't think that it would impact the sound, I'd do some sort of
slik-screen arty thing on the screens. Then they would cease being
speakers and become a design component of the room.

One thing that a lot of people don't consider is that you can do a
similar thing with wall treatments as well. You can take a neat thick
and rough fabric with a nice design and stretch it over a frame. I
made such a 3 1/2 ft square hanging stretched fabric that worked well
as a absorber that I would hang on the speakers' opposite wall. Sort
of a mild LEDE arrangement. It seemed to make a slight difference, AND
it looked like an expensive art piece, whereas it cost me about $5 for
the wood and about $15 - 20 for the fabric.

Joseph Oberlander wrote:

Ferstler posted the chart below:

31.5 Hz 20 Hz

TN1220 113 dB 106 dB
VTF-3 (20 Hz plug) 112 dB 100 dB
VTF-2 (25 Hz plug) 106 dB 90 dB
STF-1 103 dB 80 dB
Velodyne F1800 114 dB 110 dB
Velodyne HGS-15 110 dB 104 dB
Velodyne FSR-12 104 dB 97 dB
Paradigm Servo 15 112 dB 110 dB

Nice chart - thanks

This is but a small fraction of what I have on subwoofer
max-ouput measurements.

20hz @ 80db just isn't going to compete with the
five other speakers, IMO. I'd want 100db or better
in order to handle movie effects with somewhat
decent SPL. But, I guess I'm really into impact
in movies.

Well, Hsu makes no claims for the 20-Hz performance of the
sub. It is essentially rated by him down to only 30 Hz. I
did the 20-Hz measurement as a matter of policy. Actually,
there are a number of bigger and/or more expensive subs out
there that do worse. Sometimes considerably worse.

Most movies do not have much bass energy below 30 Hz,
although there are exceptions. The real expert on the
dynamics of movie bass sound is Tom Nousaine. Tom helped to
edit my third book (my second on AV), by the way.

There are also quite a few other models I have measured, but
these are ones that might interest you.

I still like the VTF-3 for the price. It gets the job
done and is a lot less expensive(and not a sluggish 15 incher)
than the Velodynes.

I have reviewed the HGS-15, as indicated above, and also
reviewed the HGS-12 and several more conventional Velodyne
models. Trust me, the Velodyne servo units are anything but
"sluggish."

Indeed, the fast-bass issue continues to mystify me, because
a sub is designed to only handle frequencies below maybe 100
Hz (or lower, of course) and the device does not need to be
"fast" to do that. The attack part of most low-bass signals
will be handled by the midrange driver, anyway, with the sub
(or woofers) just dealing with the tail attached to that
attack transient. As for the need to taper off the bass
"fast" and how some subs cannot do that, well, most musical
bass from acoustic instruments are not particularly fast
when it comes to the taper off, anyway.

Most subs seem sluggish, because they have a substantial
amount of harmonic distortion that makes them sound bloated,
or possibly the higher harmonics generated makes the signals
sound not quite so full, rich, or low. If the distortion
harmonics are high enough, they will also have an impact on
sub localization. Ironically, in some cases a sub sounds
slow, because the listening room allows a standing wave to
pile up at the listening position.

Movies, well, certainly some bass transients might taper off
fast, but the attack transients will again be handled by the
midrange drivers in the satellites. That is how the Franssen
Effect allows for those satellites to make it sound like the
bass is coming from them and not the sub. Well, the
precedence effect can also play a part, and long wavelengths
tend to not be directional, anyway, even when heard in
isolation without attack-transient clues.

In a head to head music face off, I doubt if anyone could
hear the difference between the VTF-2 and a Velodyne servo
FSR-12.

See my comments on Velodyne $1000+ for a sub is
silly.

While the FSR-12 and VTF-2 sound really similar down to 25
Hz (certainly with music and even with test tones to a
degree), below that frequency the Velodyne pulls away. With
test tones you can slightly hear differences at just about
any bass frequency below about 40 Hz when comparing a servo
Velodyne to any other good sub that is not servo controlled.
With music and movie material this really does not matter
much, but some people like the idea of really low
distortion.

I certainly would not want to give up the F1800RII in my
main system, but if it went belly up I would probably
replace it with a Hsu or SVS model. Still, the latest super
Velodyne (digital drive) models have built in equalization
to help smooth out room resonances. A good idea. Of course,
a very fine performing SVS 20-39PC Ultra I recently reviewed
in The Sensible Sound had an on-board parametric equalizer
that could null out any single peak between 20 and 80 Hz.
(One would need to be careful doing this, needless to say.)
Not bad for a unit in the price category you noted. However,
I think that the Velodyne models that have on-board
equalization also include a microphone to help the user get
the best results.

So go the subwoofer wars.

Howard Ferstler

Joseph Oberlander wrote:

Howard Ferstler wrote:

Room size should not have an impact on bass directional
clues. You could tell if the sub was quite close to the
listener, but that is only the case if it is either
generating harmonics that would be high enough in frequency
to provide localization clues or if artifacts (knick knacks,
lamps etc.) close to the sub were vibrating in sympathy.

IIRC, the O.P. said he had a huge room, so beyond 30 ft
long, or so, 50-60hz or so is still directional. The systems also
probably had the crossover improperly adjusted(and/or bad
positioning), and were getting the overamped "boomy" effect.

The best way to see if bass is directional is to disconnect
the satellites and play some bass-strong recordings. See if
the location of the sub can be pinpointed with a variety of
crossover points when at the primary listening position.

At higher frequencies (100 Hz, say) it might be possible,
but in some cases the reason is that the sub is generating
harmonics (at 200 Hz or higher with a 100-Hz primary input)
that would make localization possible. This is one rationale
for the Velodyne servo approach, which reduces such harmonic
artifacts to inaudibility. Of course, as I noted elsewhere,
if the sub is near some kind of item in the room (figurines
on shelves, a lamp or lamp shade) the resonance of that item
would also provide localization clues. Lamps sitting on subs
can cause problems like that.

However, even if slight localization clues are possible, in
most cases, once the satellites are reconnected the Franssen
Effect or the precedence effect will render them inaudible.

Howard Ferstler

On Fri, 25 Feb 2005 12:51:05 -0500, Howard Ferstler wrote:
Joseph Oberlander wrote:

Howard Ferstler wrote:

Room size should not have an impact on bass directional
clues. You could tell if the sub was quite close to the
listener, but that is only the case if it is either
generating harmonics that would be high enough in frequency
to provide localization clues or if artifacts (knick knacks,
lamps etc.) close to the sub were vibrating in sympathy.

IIRC, the O.P. said he had a huge room, so beyond 30 ft
long, or so, 50-60hz or so is still directional. The systems also
probably had the crossover improperly adjusted(and/or bad
positioning), and were getting the overamped "boomy" effect.

The best way to see if bass is directional is to disconnect
the satellites and play some bass-strong recordings. See if
the location of the sub can be pinpointed with a variety of
crossover points when at the primary listening position.

That's a *terrible* way. All you'll accomplish is being able to locate the
harmonics of the sub -- it's distortion components.

The way to test if bass is direction is just listen to the damn thing, setup
the way it is designed. Listen to some music (you do remember what music
is, right?), preferable some chamber music with a single bass player. See if
all the bass seems to be coming from where you hear the bass player. duh.

TCS wrote:

On Fri, 25 Feb 2005 12:51:05 -0500, Howard Ferstler wrote:

The best way to see if bass is directional is to disconnect
the satellites and play some bass-strong recordings. See if
the location of the sub can be pinpointed with a variety of
crossover points when at the primary listening position.

That's a *terrible* way. All you'll accomplish is being able to locate the
harmonics of the sub -- it's distortion components.

The way to test if bass is direction is just listen to the damn thing, setup
the way it is designed. Listen to some music (you do remember what music
is, right?), preferable some chamber music with a single bass player. See if
all the bass seems to be coming from where you hear the bass player. duh.

Right. However, doing it with the satellites disconnected
will greatly highlight any directional information the sub
might be generating, because there will be no satellite
signals masking the low-range soundfield. If you cannot hear
the sub's location with the satellites not operating you
certainly will not hear it when they are in operation.

Incidentally, Nico Franssen (whom I biographically profiled
in the second edition of The Encyclopedia of Recorded Sound)
proved that way back in the 1960s. With the satellites
reconnected, the precedence effect (assuming the sub is
further from the listener than the satellites, which is
often the case), will make the location-related masking even
more effective. It is also in the very nature of long
wavelengths for the source to be difficult to locate.

Regarding those long wavelengths, harmonic overtones
generated by a subwoofer and riding on the fundamentals (or
artifacts sitting close to the sub and vibrating
sympathetically) most definitely can generate location clues
that would be mistaken for directional clues in the low
bass. This is one reason that setting a lamp or some other
hard object on top of a sub can cause problems, and it is
also one reason why one should try to purchase a sub that
has very low harmonic distortion.

In any case, my guess is that what you think you are hearing
involves the fact that you *know* that the sub is "over
there" and generating sound.

Regarding music listening, I have published two books of
record reviews (one published by McFarland and the other
published by A-R Editions) and have reviewed hundreds of
recordings for The Sensible Sound. How many have you
reviewed?

Howard Ferstler

On Sun, 27 Feb 2005 14:56:59 -0500, Howard Ferstler wrote:
TCS wrote:

On Fri, 25 Feb 2005 12:51:05 -0500, Howard Ferstler wrote:

The best way to see if bass is directional is to disconnect
the satellites and play some bass-strong recordings. See if
the location of the sub can be pinpointed with a variety of
crossover points when at the primary listening position.

That's a *terrible* way. All you'll accomplish is being able to locate the
harmonics of the sub -- it's distortion components.

The way to test if bass is direction is just listen to the damn thing, setup
the way it is designed. Listen to some music (you do remember what music
is, right?), preferable some chamber music with a single bass player. See if
all the bass seems to be coming from where you hear the bass player. duh.

Right. However, doing it with the satellites disconnected
will greatly highlight any directional information the sub
might be generating, because there will be no satellite
All it'll do is let you hear what would be otherwise masked.




signals masking the low-range soundfield. If you cannot hear
the sub's location with the satellites not operating you
certainly will not hear it when they are in operation.
And if you can hear the sub's location then you've learned nothing
and certainly nothing about what the best crossover frequency is.




Incidentally, Nico Franssen (whom I biographically profiled
in the second edition of The Encyclopedia of Recorded Sound)
proved that way back in the 1960s. With the satellites
reconnected, the precedence effect (assuming the sub is
further from the listener than the satellites, which is
often the case), will make the location-related masking even
more effective. It is also in the very nature of long
wavelengths for the source to be difficult to locate.

Regarding those long wavelengths, harmonic overtones
generated by a subwoofer and riding on the fundamentals (or
artifacts sitting close to the sub and vibrating
sympathetically) most definitely can generate location clues
that would be mistaken for directional clues in the low
bass. This is one reason that setting a lamp or some other
hard object on top of a sub can cause problems, and it is
also one reason why one should try to purchase a sub that
has very low harmonic distortion.

In any case, my guess is that what you think you are hearing
involves the fact that you *know* that the sub is "over
there" and generating sound.

Regarding music listening, I have published two books of
record reviews (one published by McFarland and the other
published by A-R Editions) and have reviewed hundreds of
recordings for The Sensible Sound. How many have you
reviewed?

Howard Ferstler

TCS wrote:

On Sun, 27 Feb 2005 14:56:59 -0500, Howard Ferstler wrote:

Right. However, doing it with the satellites disconnected
will greatly highlight any directional information the sub
might be generating, because there will be no satellite

All it'll do is let you hear what would be otherwise masked.

Right. It basically is the acid test for localizing a
subwoofer. It works far more effectively than trying to do
it with the satellites hooked up.

signals masking the low-range soundfield. If you cannot hear
the sub's location with the satellites not operating you
certainly will not hear it when they are in operation.

And if you can hear the sub's location then you've learned nothing
and certainly nothing about what the best crossover frequency is.

Of course. However, you then work downward with those
crossover frequencies and find a point where the directional
clues disappear. Of course, if the sub is generating
spurious harmonics, it may not be possible to ever go low
enough. The harmonics will always make the sub's location
detectable.

In any case, I have found that 90 Hz, provided the sub is
low-pass filtered at 24 dB per octave and is not generating
audible harmonics, will work just fine. The THX people
probably would agree, but they decided to work at 80 Hz,
just to make sure.

Once you get down below about 70 Hz, you begin to run the
risk of the spaced satellite woofer systems (particularly
the left and right mains) generating suckout artifacts
between them that will cause unwanted nulls. Those
quarter-wavelength cancellations can produce the same havoc
as boundary-related suckout cancellations.

One advantage of any sub/sat configuration (aside from
obvious soundstaging advantages with the satellites and the
ability of good subwoofers to go lower than most full-range
systems) is that some of the bass suckout artifacts we get
with paired speakers playing full-bandwidth down into the
low bass will have some of those in the 50-70 Hz range
eliminated.

Howard Ferstler