Domestic sub: experiences please
 

The great leap forward! I have just installed an Behringer cross-over and
now want to
build/buy a sub to run off the low channel (variable crossover from 44 Hz
up). I've got
a 500W (genuine rms) amp to drive a sub. I should say that my listening room
is large:
7m x 5m x 2.5m so the power is not over the top. I am using a redundant car
sub as I'm
still in the experimental stage.

Results are quite good but not what I want. It really isn't up to the room
size and is a bit
flabby in its control. I'm not after a 'boom-box' sound, but need to extend
the
power response down to bowed double bass, electric bass guitar and
electronic deep
bass.

I would prefer to build rather than buy. Question is which sub driver to buy
and what
constraints are there on the design of the box. Has anyone got experience or
suggestions?
Is there a recommendable site where I can find box designs or design
suggestions? I've
had a google but its difficult to know which are sheep and goats.

Anyone's ideas, especially negative ones, gratefully received. BTW my first
impressions
of the Behringer CX3400 are very positive. Tonally neutral, very quiet, no
audible
distortion and highly controllable. For those into active speakers this
could be a good
choice. Each device can be used as 2 or 3 way stereo or mono 4 way. Only
possible
drawback for domestic users is that all connectors are XLR.
--
__________________________________________________ _______________

Peter Scott
__________________________________________________ _______________

Domestic sub: experiences please
 

Peter Scott wrote:

I would prefer to build rather than buy. Question is which sub driver
to buy and what
constraints are there on the design of the box. Has anyone got
experience or suggestions?

Sealed box. 18 or bigger driver. Precision Devices will be your friend if
you want to go low with big power and presence -

http://www.precisiondevices.co.uk/showdetails.asp?id=17

should be capable - your room should be big enough to hide it...

--
We are the keepers of the sacred words: Ni, Pang,
and Ni-wom!

Domestic sub: experiences please
 

Peter Scott wrote:

BTW my first impressions of the Behringer CX3400 are very positive.
Tonally neutral, very quiet, no audible distortion and highly
controllable.
For those into active speakers this could be a good choice. Each device
can be used as 2 or 3 way stereo or mono 4 way. Only possible
drawback for domestic users is that all connectors are XLR.

That looks an interesting bit of kit. What adapters are needed to turn it
into all phono sockets? Like, male or female XLR plug, how many (8?)?


--
Wally
www.artbywally.com/FiatPandaRally/index.htm
www.wally.myby.co.uk

Domestic sub: experiences please
 

"Wally" wrote in message
...

For those into active speakers this could be a good choice. Each device
can be used as 2 or 3 way stereo or mono 4 way. Only possible
drawback for domestic users is that all connectors are XLR.

That looks an interesting bit of kit. What adapters are needed to turn it
into all phono sockets? Like, male or female XLR plug, how many (8?)?

XLR is new to me so I am going on what it says in the Behringer
user manual. You can download these from B's site at
www.behringer.com. Unit is Super-X Pro CX3400.

The manual makes an interesting read as it also covers the theory of
loudspeaker alignment and insertion of time delays to avoid cancellation
in multiple speaker setups.The cross-over allows time delays to be put in
and gives you separate control of gain for low/mid/high bands
and control of the limiters.

If my understanding is correct you can make up a cable that connects the
balanced XLR end to an unbalanced phono or jack socket. All that happens
is the output impedance halves from 60 to 30 ohms. This should not
matter from the cross-over into the kilohm input impedances of the amps.

Please ignore if this is all known to you. XLR has a conductor for both
live and return (L and R) and they are twisted together like cat5 to cancel
out
magnetic interference. There is a separate screen connected to the third pin
called X for external. For XLR to XLR the screen is broken at the receiving
end to avoid hum loops. For XLR to unbalanced the screen and return are
joined at one end. XLR signals go in the direction the pins point, so
outputs
have pins sticking out, that is they are male plugs even though on the
chassis.
I find this weird, the opposite of mains practice.

I am inputting from the XLR output from a Cyrus Pre pre-amp. If you were
sending from an unbalanced phono pre-amp output then you would need
another cable the reverse of what I've said above. Alternatively you could
use
Direct Injection (DI) boxes like the ones the pros use for unbalanced
mikes and guitars.

The cross-over has two input XLRs and six XLR outputs, two for bass
(one used if summed), two for mid/high and two for high if a three way
set-up is used. Four of the six are used for four-way mono use.

By the way I can recommend www.studiospares.com. They are a
Behringer dealer and are friendly, reliable and speedy. Good source
connectors and cables and stuff like DI boxes.

The low price of Behringer stuff 80-some ukp plus VAT for the
Xover makes it possible to buy one to play with perhap? I am also
moving to professional power. I am trying the InterM devices. At
present an R500plus in stereo mode driving Mordaunt Short 55Ti
speakers of some vintage and a bridged R500 to give the oomph
for the sub. So far very pleasing.

Peter Scott

Domestic sub: experiences please
 

Peter Scott wrote:

XLR is new to me so I am going on what it says in the Behringer
user manual. You can download these from B's site at
www.behringer.com. Unit is Super-X Pro CX3400.

Thanks for that - I'll have a read.


... so outputs
have pins sticking out, that is they are male plugs even though on the
chassis.
I find this weird, the opposite of mains practice.

I'm glad you mentioned that - I found a place that does XLR-to-phono
adapters, and thought the signal ends would have sockets...


I am inputting from the XLR output from a Cyrus Pre pre-amp. If you
were sending from an unbalanced phono pre-amp output then you would
need another cable the reverse of what I've said above. Alternatively
you could use Direct Injection (DI) boxes like the ones the pros use
for unbalanced mikes and guitars.

Doesn't a DI box convert the unbalanced phono signal to a balanced one with
the correct impedance? Unless it also works in reverse, it wouldn't help
with the connections from crossover to amps. Consdering the cost of DI boxes
(about a tenner per signal), I think adapters is probably the way to go. I
was wondering about the connection from unbalanced preamp to the crossover,
but the manual says the input impedance is 50K balanced, 25K unbalanced,
which I think should be okay.


The cross-over has two input XLRs and six XLR outputs, two for bass
(one used if summed), two for mid/high and two for high if a three way
set-up is used. Four of the six are used for four-way mono use.

Yup. So, inputs are sockets, requiring a connector with pins, and outputs
have pins, requiring a connector with sockets, yes?


By the way I can recommend www.studiospares.com. They are a
Behringer dealer and are friendly, reliable and speedy. Good source
connectors and cables and stuff like DI boxes.

The low price of Behringer stuff 80-some ukp plus VAT for the
Xover makes it possible to buy one to play with perhap?

If it's as clean as you suggest, it sounds like a much easier way for me to
try out my tri-amping idea. I was going to cobble something together by
attempting to make my own filters (ie, tweak standard circuits, because I
don't really know what I'm doing), but, at that price, it just isn't worth
the effort.


I am also
moving to professional power. I am trying the InterM devices. At
present an R500plus in stereo mode driving Mordaunt Short 55Ti
speakers of some vintage and a bridged R500 to give the oomph
for the sub. So far very pleasing.

These R500 thingies are PA amps?


--
Wally
www.artbywally.com/FiatPandaRally/index.htm
www.wally.myby.co.uk

Domestic sub: experiences please
 

In article ,
Peter Scott wrote:
For XLR to unbalanced the screen and return are joined at one end. XLR
signals go in the direction the pins point, so outputs have pins
sticking out, that is they are male plugs even though on the chassis. I
find this weird, the opposite of mains practice.

The reason for this is that the XLR is also used for microphones which may
be phantom powered. And this is 48 volts - so not 'safe'. So in this case,
the male and females are arranged for the flow of power into the mic, not
the signal coming from it. And line, rather than mic level applications
now follow this convention for convenience. It wasn't always so. Older
Nagra tape recorders, for example, used females as outputs.

The change came somewhere around the '60s as phantom arrived - but some
makers took a long time to use the now standard 'wrong' way round.

The exception is 100 volt line speakers. They should be arranged the
'correct' way round as they also carry dangerous voltages. Although
hopefully any new 100 volt gear won't use XLR anyway - Speakon is better.

--
*Avoid clichés like the plague. (They're old hat.) *

Dave Plowman London SW
To e-mail, change noise into sound.

Domestic sub: experiences please
 

"Wally" wrote in message
...


I'm glad you mentioned that - I found a place that does XLR-to-phono
adapters, and thought the signal ends would have sockets...


Doesn't a DI box convert the unbalanced phono signal to a balanced one
with
the correct impedance? Unless it also works in reverse, it wouldn't help

Yes. I was meaning it could be used to connect unbalanced pre-amp to
balanced Xover input.

Yup. So, inputs are sockets, requiring a connector with pins, and outputs
have pins, requiring a connector with sockets, yes?

Yes. The way I remember is that the pins point in the direction of the
signal.

If it's as clean as you suggest, it sounds like a much easier way for me
to
try out my tri-amping idea. I was going to cobble something together by
attempting to make my own filters (ie, tweak standard circuits, because I
don't really know what I'm doing), but, at that price, it just isn't worth
the effort.

You appreciate I've only had it a few days so these are first impressions.
They are so far very good. The Xover filters are 24dB/octave and are
infinitely
variable. Great tweaking!

These R500 thingies are PA amps?

Sort of. They're at the high end of quality. THD is alleged to be 0.05%
but the small print is that this is in bridged mode which I guess would
reduce crossover distortion? However by underrunning the amp the
spec implies an THD almost as low. If you're interested you can
download specs from www.inter-m.com. Its Korean, so now I've
got a Korean car, a Korean phone and Korean amps. I've been using
a 500 for a few months for the main speakers and sufficiently
pleased to get another for the sub. On a car 10" sub I am just into
clipping would you believe, but a larger diameter driver will give
me more efficiency I am sure. The units are rack mounting, as is
the Xover, so I am scratching my head for a decent looking rack design.
The reason I chose the R500 is that it has no fan. The larger ones do.

I know this is heresy but I've always believed that the key to clean
loud sound is a big tightly controlled loudspeaker driven by loads
of power and not to worry too much about THD.
Since I replaced a Marantz 60 wpc with the R500 the crispness
and solidity has gone up. I was about to junk the Mordaunts for lack
of sparkle.

Peter Scott

Domestic sub: experiences please
 

Peter Scott wrote:

You appreciate I've only had it a few days so these are first
impressions. They are so far very good. The Xover filters are
24dB/octave and are infinitely variable. Great tweaking!

I have to say, I'm very tempted. Since it seems to be touted as suitable for
studio monitoring, one would assume that it's good enough for decent home
audio (if not mega-audiophile standards, whatever they are). At around 90
quid, it just seems incredibly cheap. (The little Behringer mixers, starting
at about 25 quid, look like amazing value as well.)


These R500 thingies are PA amps?

Sort of. They're at the high end of quality. THD is alleged to be
0.05% but the small print is that this is in bridged mode which I
guess would reduce crossover distortion? However by underrunning the
amp the
spec implies an THD almost as low. If you're interested you can
download specs from www.inter-m.com.

Done some looking - they're a bit out of my price range, although the R300
looks interesting for driving the bass end. My amplifier plan as it stands
is a pile of Cyrus 2s (got one, need two more).


Its Korean, so now I've
got a Korean car, a Korean phone and Korean amps. I've been using
a 500 for a few months for the main speakers and sufficiently
pleased to get another for the sub. On a car 10" sub I am just into
clipping would you believe, but a larger diameter driver will give
me more efficiency I am sure.

Is the sub being driven by a bridged R500?


The units are rack mounting, as is
the Xover, so I am scratching my head for a decent looking rack
design.

TBH, I'd be tempted to hide all this stuff - unless you want your living
room to look like a studio control room. :-)


The reason I chose the R500 is that it has no fan. The larger
ones do.

Good point.


I know this is heresy but I've always believed that the key to clean
loud sound is a big tightly controlled loudspeaker driven by loads
of power and not to worry too much about THD.

I could go with this - seems to me that the best kind of clipping is no
clipping, so 'sufficient power' should be that which provides the headroom
to handle transients at one's maximum preferred in-room volume.


Since I replaced a Marantz 60 wpc with the R500 the crispness
and solidity has gone up. I was about to junk the Mordaunts for lack
of sparkle.

What's the spec power handling of the Mordaunts?


--
Wally
www.artbywally.com/FiatPandaRally/index.htm
www.wally.myby.co.uk

Domestic sub: experiences please
 

..
I have to say, I'm very tempted. Since it seems to be touted as suitable
for
studio monitoring, one would assume that it's good enough for decent home
audio (if not mega-audiophile standards, whatever they are). At around 90
quid, it just seems incredibly cheap. (The little Behringer mixers,
starting
at about 25 quid, look like amazing value as well.)

There has been a lot of discussion about Behringer on US news groups such
as rec.audio.pro. The pros really don't want to admit it but are forced to
accept
that after initial reliability problems B offers high specs at amazingly low
prices. It seems that Uli B who runs the company keeps his ear to the
ground and is always willing to talk and listen to users.


Is the sub being driven by a bridged R500?

At present its a dual coil and bi-amped from the two channels. I intend to
bridge and drive a single coil when I decide on a sub design and driver.
That was the original reason for this thread!


TBH, I'd be tempted to hide all this stuff - unless you want your living
room to look like a studio control room. :-)

Well form follows function if you follow the Bauhaus principles (tho
I've heard this changed nowadays to 'form follows finance!'). I'd
like to think that I can design summat that looks good. Sort of
minimalist. Only real problem is the mass of cable. Oh well, praps
it'll have to go back in the antique pine cupboard that I've used up
to now.


I could go with this - seems to me that the best kind of clipping is no
clipping, so 'sufficient power' should be that which provides the headroom
to handle transients at one's maximum preferred in-room volume.

Couldn't put it better. The worst kind of distortion is clipping, even
when its the soft variety. I used to use a NAD amp with soft clip and it
wasn't too bad. Smaller room then of course. But nothing works
better than headroom. Sharp corners on the waves generate oodles
of hf harmonics, especially in modern amps with a vast frequency
spectrum.

What's the spec power handling of the Mordaunts?

Nominally 150W pc but protected at 300W according to a reply to my
previous thread here. Used to shut down my Marantz when listening to
Pink Floyd or Joe Zawinul. BTW I've got a CD brought in from Hong
Kong that has the most amazing bass drums and percussion. Apparently
they all use it to test their systems over there. Yim Hok-Man
8.225942 HDCD on the Marco Polo label.

BTW Cyrus kit often turns up on eBay. That's where I got my Pre.

--
Wally
www.artbywally.com/FiatPandaRally/index.htm
www.wally.myby.co.uk

Domestic sub: experiences please
 

Peter Scott wrote:

Couldn't put it better. The worst kind of distortion is clipping, even
when its the soft variety.

What's the spec power handling of the Mordaunts?


Nominally 150W pc but protected at 300W according to a reply to my
previous thread here. Used to shut down my Marantz when listening to
Pink Floyd or Joe Zawinul.

An amp with taste?

BTW I've got a CD brought in from Hong
Kong that has the most amazing bass drums and percussion. Apparently
they all use it to test their systems over there. Yim Hok-Man
8.225942 HDCD on the Marco Polo label.

You hate soft clipping yet love this HDCD?
I suppose you and everyone in Hong Kong have HDCD players.

--
Eiron.