Another sub-bass option
 

Dave Plowman wrote:

: In article ,
: Arny Krueger wrote:
: If money is tight, auction off the B139s and use the cash to buy a real
: subwoofer driver.
:
: Oh, and if you are building a subwoofer, forget transmission lines. They
: are basically a waste of good box volume.
:
: More sacrilege from Arny. But true. I've never come across a pro
: transmission line speaker, and for good reasons.

Well, more straight talk from Arny ... a loosely chosen entry point!
OTOH, I've been following the thread, as I've a pair of B139's too;-)

AAMOF I hauled them out of a pair of small "TL"s I bought (with early
T27 variant, B110 (unknown label-off variant)) and reduced the cases
to face-down "speaker stands" interim because they sounded so bad,
with old stuffing etc, and besides I needed a temporary replacement
for the one blown T27's in my kitchen Kef 104ab set - but I digress!

Straight talk or not, I've total sympathy with the OP's desire to do
what he can with what he has, especially with budget considerations,
and I'm saving the B139's (and the B110's in case an alternate idea
for a better cabinet arrangement .... looking at the really basic TL I
bought, it could be turned sideways and possibly extended ... as per
http://www.t-linespeakers.org/design/foldings/tttl.html ... maybe ...

But my main point was going to be ... and I hold this out as a
potential future project of my own, all comments appreciated;- -
what about considering the "coffin" dual TL supposedly sub at
http://www.t-linespeakers.org/classics/coffin/
and especially, obviously the details at the "Perfectionist Audio"
link therein,
http://www.hogheaven.com/diyaudio/su...PATL/patl.html
as a possibility for using a spare pair of B139's up?

OK, it requires a little work in the timber dept, but why not?
It might seem to have capabilities beyond the usual, anyway.

[Cheers!]

RdM

"Big is better, and biggest is best" (;=}))
William S. Burroughs as lead dinosaur in some song skit, somewhere

[and the reason I'm delaying mine is because I'd never get it down the
stairs on a move ... but it's definitely a considered future project!]

Another sub-bass option
 

Stewart Pinkerton wrote:

I'm not whining. I also wasn't looking for new drivers. Arny
suggested the JL ones, but the UK price turned out to be too dear.

You'll find that Volt drivers are also expensive. Good bass drivers
*are* both large and expensive. They're also *necessary*, if you want
clean bass at high levels.

At no point did I say I wanted clean bass at high levels. In an earlier
thread, about bi-amping, I said that I rarely use my 20Wpc amp over half
volume for full program material. I gather an isobaric enclosure needs more
power than one using a single driver, but I don't think my needs would
dictate something in the multiple hundreds of Watts category - maybe
30-40Wpc?


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

Another sub-bass option
 

Stewart Pinkerton wrote:

I'm not whining. I also wasn't looking for new drivers. Arny
suggested the JL ones, but the UK price turned out to be too dear.

You'll find that Volt drivers are also expensive. Good bass drivers
*are* both large and expensive. They're also *necessary*, if you want
clean bass at high levels.

At no point did I say I wanted clean bass at high levels. In an earlier
thread, about bi-amping, I said that I rarely use my 20Wpc amp over half
volume for full program material. I gather an isobaric enclosure needs more
power than one using a single driver, but I don't think my needs would
dictate something in the multiple hundreds of Watts category - maybe
30-40Wpc?


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

Another sub-bass option
 

On Thu, 09 Oct 2003 14:06:26 GMT, "Wally" wrote:

Stewart Pinkerton wrote:

I'm not whining. I also wasn't looking for new drivers. Arny
suggested the JL ones, but the UK price turned out to be too dear.

You'll find that Volt drivers are also expensive. Good bass drivers
*are* both large and expensive. They're also *necessary*, if you want
clean bass at high levels.

At no point did I say I wanted clean bass at high levels. In an earlier
thread, about bi-amping, I said that I rarely use my 20Wpc amp over half
volume for full program material. I gather an isobaric enclosure needs more
power than one using a single driver, but I don't think my needs would
dictate something in the multiple hundreds of Watts category - maybe
30-40Wpc?

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Another sub-bass option
 

On Thu, 09 Oct 2003 14:06:26 GMT, "Wally" wrote:

Stewart Pinkerton wrote:

I'm not whining. I also wasn't looking for new drivers. Arny
suggested the JL ones, but the UK price turned out to be too dear.

You'll find that Volt drivers are also expensive. Good bass drivers
*are* both large and expensive. They're also *necessary*, if you want
clean bass at high levels.

At no point did I say I wanted clean bass at high levels. In an earlier
thread, about bi-amping, I said that I rarely use my 20Wpc amp over half
volume for full program material. I gather an isobaric enclosure needs more
power than one using a single driver, but I don't think my needs would
dictate something in the multiple hundreds of Watts category - maybe
30-40Wpc?

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Another sub-bass option
 

Stewart Pinkerton wrote:



Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.


Can I have a little rant?

This thread was about KEF B139s.

If you look at a B139, not with rose-tinted glasses,
but as the woofer in a domestic hi-fi setup, it is excellent.

Maybe it doesn't work as an AV sub to reproduce helicopters
and explosions at window shattering levels but in a reflex box
with -3dB at ~32 Hz or a TL with -10dB at ~20Hz it sounds
pretty damn' good on all of my CDs and vinyl.

What's more, a B139 still works after 30 years, unlike foam-surround
woofers that are dead at 10 years or other newish materials that lose
their shape and fall off (some sort of Goodmans loudspeaker)

So I may buy new speakers, but KEFs will be playing at my funeral. :-)

Thanks,

Roger.

Another sub-bass option
 

Stewart Pinkerton wrote:



Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.


Can I have a little rant?

This thread was about KEF B139s.

If you look at a B139, not with rose-tinted glasses,
but as the woofer in a domestic hi-fi setup, it is excellent.

Maybe it doesn't work as an AV sub to reproduce helicopters
and explosions at window shattering levels but in a reflex box
with -3dB at ~32 Hz or a TL with -10dB at ~20Hz it sounds
pretty damn' good on all of my CDs and vinyl.

What's more, a B139 still works after 30 years, unlike foam-surround
woofers that are dead at 10 years or other newish materials that lose
their shape and fall off (some sort of Goodmans loudspeaker)

So I may buy new speakers, but KEFs will be playing at my funeral. :-)

Thanks,

Roger.

Another sub-bass option
 

On Thu, 09 Oct 2003 23:59:29 +0100, Old Fart at Play
wrote:

Stewart Pinkerton wrote:

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.

Can I have a little rant?

This thread was about KEF B139s.

If you look at a B139, not with rose-tinted glasses,
but as the woofer in a domestic hi-fi setup, it is excellent.

Um, it's a decent woofer, but was overtaken many years ago by more
modern constructions, viz KEFs own 'racetrack' woofers in their
current range.

Maybe it doesn't work as an AV sub to reproduce helicopters
and explosions at window shattering levels but in a reflex box
with -3dB at ~32 Hz or a TL with -10dB at ~20Hz it sounds
pretty damn' good on all of my CDs and vinyl.

Granted, it was never designed for subwoofer duties, and comes from an
era when reproduction below 30Hz was almost an irrelevance, i.e. the
days when vinyl was king.

What's more, a B139 still works after 30 years, unlike foam-surround
woofers that are dead at 10 years or other newish materials that lose
their shape and fall off (some sort of Goodmans loudspeaker)

Well, that's true of any other speaker with a rubber surround. In
fact, over forty years or so of audiophilia, and several dozen pairs
of speakers, I don't think I have ever owned speakers with a foam
surround. The 'other newish materials' you sweepingly denigrate are in
the main responsible for great advances in sound reproduction.
Goodmans haven't made a decent speaker in 30 years, so they are hardly
a good target.

So I may buy new speakers, but KEFs will be playing at my funeral. :-)

Ah now, a *real* audiophile would have gone for Quad '57s! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Another sub-bass option
 

On Thu, 09 Oct 2003 23:59:29 +0100, Old Fart at Play
wrote:

Stewart Pinkerton wrote:

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.

Can I have a little rant?

This thread was about KEF B139s.

If you look at a B139, not with rose-tinted glasses,
but as the woofer in a domestic hi-fi setup, it is excellent.

Um, it's a decent woofer, but was overtaken many years ago by more
modern constructions, viz KEFs own 'racetrack' woofers in their
current range.

Maybe it doesn't work as an AV sub to reproduce helicopters
and explosions at window shattering levels but in a reflex box
with -3dB at ~32 Hz or a TL with -10dB at ~20Hz it sounds
pretty damn' good on all of my CDs and vinyl.

Granted, it was never designed for subwoofer duties, and comes from an
era when reproduction below 30Hz was almost an irrelevance, i.e. the
days when vinyl was king.

What's more, a B139 still works after 30 years, unlike foam-surround
woofers that are dead at 10 years or other newish materials that lose
their shape and fall off (some sort of Goodmans loudspeaker)

Well, that's true of any other speaker with a rubber surround. In
fact, over forty years or so of audiophilia, and several dozen pairs
of speakers, I don't think I have ever owned speakers with a foam
surround. The 'other newish materials' you sweepingly denigrate are in
the main responsible for great advances in sound reproduction.
Goodmans haven't made a decent speaker in 30 years, so they are hardly
a good target.

So I may buy new speakers, but KEFs will be playing at my funeral. :-)

Ah now, a *real* audiophile would have gone for Quad '57s! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Another sub-bass option
 

(Stewart Pinkerton) wrote in message ...


So I may buy new speakers, but KEFs will be playing at my funeral. :-)

Ah now, a *real* audiophile would have gone for Quad '57s! :-)

But you can't be buried in an ESL57.

http://www.t-linespeakers.org/classics/coffin

Roger.

Another sub-bass option
 

(Stewart Pinkerton) wrote in message ...


So I may buy new speakers, but KEFs will be playing at my funeral. :-)

Ah now, a *real* audiophile would have gone for Quad '57s! :-)

But you can't be buried in an ESL57.

http://www.t-linespeakers.org/classics/coffin

Roger.

Another sub-bass option
 

Stewart Pinkerton wrote:

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.

If we assume that the main amp is typically supplying 10Wpc to the mid/top
drivers, what sort of power would be needed from an amp driving a pair of
isobaric bass cabs loaded with B139s? Lets say the bass cabs are sealed
boxes of about 80L each.


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

Another sub-bass option
 

Stewart Pinkerton wrote:

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.

If we assume that the main amp is typically supplying 10Wpc to the mid/top
drivers, what sort of power would be needed from an amp driving a pair of
isobaric bass cabs loaded with B139s? Lets say the bass cabs are sealed
boxes of about 80L each.


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

Another sub-bass option
 

"Stewart Pinkerton" wrote in message


IOW, check out UK-made Volt drivers,

http://www.voltloudspeakers.co.uk/Lo...tudiorange-opt.
jpg

then stop whining.

Actually, if you compare the technical specs of Volt drivers to the
competitive JL audio drivers, there's plenty for UK buyers to whine about.

Here's a summary from which UK & European sources can be culled.

http://ldsg.snippets.org/sect-12-byEBP.php3#WOOF12-

Just remember, subwoofer performance is dominated by cone diameter and Xmax.

Another sub-bass option
 

"Stewart Pinkerton" wrote in message


IOW, check out UK-made Volt drivers,

http://www.voltloudspeakers.co.uk/Lo...tudiorange-opt.
jpg

then stop whining.

Actually, if you compare the technical specs of Volt drivers to the
competitive JL audio drivers, there's plenty for UK buyers to whine about.

Here's a summary from which UK & European sources can be culled.

http://ldsg.snippets.org/sect-12-byEBP.php3#WOOF12-

Just remember, subwoofer performance is dominated by cone diameter and Xmax.

Another sub-bass option
 

On Fri, 10 Oct 2003 14:26:48 GMT, "Wally" wrote:

Stewart Pinkerton wrote:

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.

If we assume that the main amp is typically supplying 10Wpc to the mid/top
drivers, what sort of power would be needed from an amp driving a pair of
isobaric bass cabs loaded with B139s? Lets say the bass cabs are sealed
boxes of about 80L each.

You'll be looking at something like 86dB/w/m basic sensitivity from
the B139s (although a fairly tough 4 ohms or less loading), so this
will entirely depend on the sensitivity of your main speakers. Note
also that if you are *typopically * supplying 10 watts to the main
speakers, you'll need at least 50 watts to handle peaks, so you'd have
to be looking at a minimum of 50-100 watt amplifier, with enough
current reserves to handle say a 3 ohm load without buckling. Note
that if you want to keep the bass response flat down to 20-25Hz,
you'll have to use active equalisation, and boost the bass by some
6-10dB. That's *4-10 times* the 'midband' power!

To give you some idea, I use some 11dB of bass equalisation in the
20-30Hz range on a pair of Tannoy 633s that I use for TV sound. These
are 90dB/w/m speakers which take about 3-5 watts of average drive on
action movies with the equaliser out of circuit. When it's in circuit
on a good 'blockbuster' like T2 or U-571, then my Audiolab 8000P,
which puts out a measured 195 watts/channel continuous into 4 ohms,
sometimes clips on the loud stuff...........
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Another sub-bass option
 

On Fri, 10 Oct 2003 14:26:48 GMT, "Wally" wrote:

Stewart Pinkerton wrote:

Nope. If you look at the volume of air you need to shift at 20Hz to
obtain even 100dB (not a particularly loud peak level), then you need
a *lot* of power! This is why decent commercial subs invariably have
several hundred watt amps, some go up to a kilowatt!.

If we assume that the main amp is typically supplying 10Wpc to the mid/top
drivers, what sort of power would be needed from an amp driving a pair of
isobaric bass cabs loaded with B139s? Lets say the bass cabs are sealed
boxes of about 80L each.

You'll be looking at something like 86dB/w/m basic sensitivity from
the B139s (although a fairly tough 4 ohms or less loading), so this
will entirely depend on the sensitivity of your main speakers. Note
also that if you are *typopically * supplying 10 watts to the main
speakers, you'll need at least 50 watts to handle peaks, so you'd have
to be looking at a minimum of 50-100 watt amplifier, with enough
current reserves to handle say a 3 ohm load without buckling. Note
that if you want to keep the bass response flat down to 20-25Hz,
you'll have to use active equalisation, and boost the bass by some
6-10dB. That's *4-10 times* the 'midband' power!

To give you some idea, I use some 11dB of bass equalisation in the
20-30Hz range on a pair of Tannoy 633s that I use for TV sound. These
are 90dB/w/m speakers which take about 3-5 watts of average drive on
action movies with the equaliser out of circuit. When it's in circuit
on a good 'blockbuster' like T2 or U-571, then my Audiolab 8000P,
which puts out a measured 195 watts/channel continuous into 4 ohms,
sometimes clips on the loud stuff...........
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Another sub-bass option
 

Stewart Pinkerton wrote:


that if you want to keep the bass response flat down to 20-25Hz,
you'll have to use active equalisation, and boost the bass by some
6-10dB. That's *4-10 times* the 'midband' power!

To give you some idea, I use some 11dB of bass equalisation in the
20-30Hz range on a pair of Tannoy 633s that I use for TV sound.



Can anyone recommend any music CDs with something in the 20-30Hz range?

Roger.

Another sub-bass option
 

Stewart Pinkerton wrote:


that if you want to keep the bass response flat down to 20-25Hz,
you'll have to use active equalisation, and boost the bass by some
6-10dB. That's *4-10 times* the 'midband' power!

To give you some idea, I use some 11dB of bass equalisation in the
20-30Hz range on a pair of Tannoy 633s that I use for TV sound.



Can anyone recommend any music CDs with something in the 20-30Hz range?

Roger.

Another sub-bass option
 

In article , Stewart Pinkerton
wrote:
On Fri, 10 Oct 2003 14:26:48 GMT, "Wally" wrote:


To give you some idea, I use some 11dB of bass equalisation in the
20-30Hz range on a pair of Tannoy 633s that I use for TV sound. These
are 90dB/w/m speakers which take about 3-5 watts of average drive on
action movies with the equaliser out of circuit. When it's in circuit on
a good 'blockbuster' like T2 or U-571, then my Audiolab 8000P, which
puts out a measured 195 watts/channel continuous into 4 ohms, sometimes
clips on the loud stuff...........

Are you sure it is the amp clipping as distinct from the speakers reaching
the end of their travel or becoming nonlinear? - i.e. have you measured the
waveforms when this is happening?

I ask because when I was testing amps at high powers many years ago I often
heard 'clipping' at LF, but tests showed that in many cases the amp output
waveform was fine. It was often the speaker that was running into trouble.
In some cases moderate signal nonlinearity was causing the cones to 'creep'
and this reduced the level at which LF would cause the speakers to 'clip'.
A visual sign was the cones seeming to 'suck in' or 'push out' of the
cabinet as this happened. I have never tried the Tannoys you're using,
though, so the speakers I was using may have been rather more limited in
terms of the cone displacements they could handle.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Another sub-bass option
 

In article , Stewart Pinkerton
wrote:
On Fri, 10 Oct 2003 14:26:48 GMT, "Wally" wrote:


To give you some idea, I use some 11dB of bass equalisation in the
20-30Hz range on a pair of Tannoy 633s that I use for TV sound. These
are 90dB/w/m speakers which take about 3-5 watts of average drive on
action movies with the equaliser out of circuit. When it's in circuit on
a good 'blockbuster' like T2 or U-571, then my Audiolab 8000P, which
puts out a measured 195 watts/channel continuous into 4 ohms, sometimes
clips on the loud stuff...........

Are you sure it is the amp clipping as distinct from the speakers reaching
the end of their travel or becoming nonlinear? - i.e. have you measured the
waveforms when this is happening?

I ask because when I was testing amps at high powers many years ago I often
heard 'clipping' at LF, but tests showed that in many cases the amp output
waveform was fine. It was often the speaker that was running into trouble.
In some cases moderate signal nonlinearity was causing the cones to 'creep'
and this reduced the level at which LF would cause the speakers to 'clip'.
A visual sign was the cones seeming to 'suck in' or 'push out' of the
cabinet as this happened. I have never tried the Tannoys you're using,
though, so the speakers I was using may have been rather more limited in
terms of the cone displacements they could handle.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Another sub-bass option
 

Dave Plowman wrote:

More sacrilege from Arny. But true. I've never come across a pro
transmission line speaker, and for good reasons.

Err, PMC make rather a lot of them. But I guess you've never come
across one, so...

Andrew.

Another sub-bass option
 

Dave Plowman wrote:

More sacrilege from Arny. But true. I've never come across a pro
transmission line speaker, and for good reasons.

Err, PMC make rather a lot of them. But I guess you've never come
across one, so...

Andrew.