[john]

Is there a program to plot frequency response of a receiver+speakers in real
time (or within a few seconds), to allow me to tweak the equalizer?

The tools I already have:

receiver, speakers
hardware function (wave) generator
laptop computer (with sound output and mic input)
oscilloscope
measurement microphone (behringer ecm8000)
mic pre-amp mixer with analog and USB port output

I assume the soundcard in the laptop does not have a flat response curve
(both input and output), so the software should have some way to
calibrate/compensate for this.

When I google for sweep spectrum analyzer software, I found lots of hits.
Please help me narrow down the choices that make the best use of the tools I
have. Obviously, free software is preferred.

[Don Pearce[_3_]]

On Thu, 19 Mar 2009 05:54:07 -0700, "john" wrote:

Is there a program to plot frequency response of a receiver+speakers in real
time (or within a few seconds), to allow me to tweak the equalizer?

The tools I already have:

receiver, speakers
hardware function (wave) generator
laptop computer (with sound output and mic input)
oscilloscope
measurement microphone (behringer ecm8000)
mic pre-amp mixer with analog and USB port output

I assume the soundcard in the laptop does not have a flat response curve
(both input and output), so the software should have some way to
calibrate/compensate for this.

When I google for sweep spectrum analyzer software, I found lots of hits.
Please help me narrow down the choices that make the best use of the tools I
have. Obviously, free software is preferred.

I know that intuitively this feels like it should be easy. Many, many
people before you have felt the same thing. In practice it simply
can't be done because the biggest factor determining the frequency
response is the sum of all possible paths between speaker and ear in
the room, which cannot be compensated.

OK, theoretically, if you could hold your ear steady at one spot
(within a millimetre or so), and nothing in the room ever moved, it
could be done, but that is really rather impracticable. Also, it would
only work for one ear, leaving the other one out in the cold. Bear in
mind that in a typical room it is quite common to get 20 or 30dB
difference between ears for individual notes because of moding.

So no, don't waste your time. If you have tone controls, adjust them
for the best overall sound.

d

[[email protected]]

On Mar 19, 8:54*am, "john" wrote:
Is there a program to plot frequency response of a receiver+speakers in real
time (or within a few seconds), to allow me to tweak the equalizer?

The tools I already have:

receiver, speakers
hardware function (wave) generator
laptop computer (with sound output and mic input)
oscilloscope
measurement microphone (behringer ecm8000)
mic pre-amp mixer with analog and USB port output

I assume the soundcard in the laptop does not have a flat response curve
(both input and output), so the software should have some way to
calibrate/compensate for this.

When I google for sweep spectrum analyzer software, I found lots of hits.
Please help me narrow down the choices that make the best use of the tools I
have. Obviously, free software is preferred.


see the real time analyzer (RTA) he

http://www.marchandelec.com/programs.html

Mark

[Ethan Winer[_2_]]

Is there a program to plot frequency response of a receiver+speakers in real
time (or within a few seconds), to allow me to tweak the equalizer?

Don already gave you the right answer. EQ'ing speakers is futile for
many reasons. This article explains the issues in depth:

http://www.realtraps.com/art_audyssey.htm

--Ethan

[Mike Rivers]

john wrote:
Is there a program to plot frequency response of a receiver+speakers in
real time (or within a few seconds), to allow me to tweak the equalizer?

The class of program that does this is called a Real Time Analyzer, but as
has already been explained to you, using an RTA to adjust an equalizer
(presumably for flat response) only works if you have a very good acoustic
environment and know how to interpret multiple measurements. The tool
best suited for smoothing the frequency response in a room is a hammer,
not a computer program.

I assume the soundcard in the laptop does not have a flat response curve
(both input and output), so the software should have some way to
calibrate/compensate for this.

Even the poorest sound card has far flatter frequency response than the room
you're measuring. However, you'll need a microphone to make your
measurements
and the microphone probably won't be as flat as the sound card's frequency
response unless you buy or rent a real measurement mic.

Please help me narrow down the choices that make the best use of
the tools I have. Obviously, free software is preferred.

The best tool is free. It's your own ears. Twiddle the knobs until it
sounds good
to you and enjoy. Anyone who tries to sell you a system for fixing your
room
electronically is selling you a bill of goods, unless you always listen
in only one spot,


--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[Ethan Winer[_2_]]

Wise advice Mike, as always. Just a few comments.

On Mar 19, 12:50 pm, Mike Rivers wrote:
The best tool is free. It's your own ears. Twiddle the knobs until it
sounds good to you and enjoy.

One problem with trying to "tune a room" by ear is the music you play
may or may not be in a key that aligns with the room's resonances. A
tune In the key of G may not excite room modes that are terribly boomy
for the key of A.

Anyone who tries to sell you a system for fixing your room
electronically is selling you a bill of goods, unless you always listen
in only one spot,

It's even worse than that. I've measured very large changes across
distances of only a few inches, even at very low frequencies. This
article addresses a different issue, but the graph makes the point
very well:

http://www.ethanwiner.com/believe.html

--Ethan

[Mike Rivers]

On Mar 20, 11:39 am, Ethan Winer wrote:
Wise advice Mike, as always. Just a few comments.

On Mar 19, 12:50 pm, Mike Rivers wrote:

One problem with trying to "tune a room" by ear is the music you play
may or may not be in a key that aligns with the room's resonances. A
tune In the key of G may not excite room modes that are terribly boomy
for the key of A.

Well, you have to take an earball average across a reasonable cross
section of material that you like to listen to. And that won't make a
mastering-grade room, it will just make music more pleasant to listen
to. But that goes a long way toward making decent mixes.

[RD Jones]

On Mar 19, 7:54*am, "john" wrote:
Is there a program to plot frequency response of a receiver+speakers in real
time (or within a few seconds), to allow me to tweak the equalizer?

The tools I already have:

receiver, speakers
hardware function (wave) generator
laptop computer (with sound output and mic input)
oscilloscope
measurement microphone (behringer ecm8000)
mic pre-amp mixer with analog and USB port output

Add my voice to the din saying you can't correct for the response
of the system _in the room_. The physical properties of the room
can only be corrected by physical treatment, not by electronic means.
Understanding that, what you can do is compensate for the response
of the speaker(s). The speaker is, by far, the most difficult and
expensive to get to respond flat (assuming flat is what you're after).

The problem is that the typical (undisclosed) EQ's band adjustments
are so wide that they're not very useful for correcting a speaker's
fairly narrow peaks and dips. You'll also need to make your
measurements in as nearly ideal conditions as possible such as
outdoors where there's no room reflections and resonances.

I assume the soundcard in the laptop does not have a flat response curve
(both input and output), so the software should have some way to
calibrate/compensate for this.

The sound card will likely be the flatest responding link in the
chain,
assuming use of a true line input. (the ECM8000 is not truely flat
either)

When I google for sweep spectrum analyzer software, I found lots of hits.
Please help me narrow down the choices that make the best use of the tools I
have. Obviously, free software is preferred.

Most of the programs in use by those in this group will already have
some sort of built-in spectral tool (Sound Forge, CoolEdit/Audition,
etc)
or use a DX or VST plug-in to accomplish the task. Not really free.

I'm thinking you'd like something of a stand-alone app:

"VA Visual Analyser" is free and works as good as any
stand alone app I've tried.

http://www.hitsquad.com/smm/programs/VA/

There's also RightMark Audio Analyser.

rd

[[email protected]]

On Mar 19, 5:54*am, "john" wrote:
Is there a program to plot frequency response of a receiver+speakers in real
time (or within a few seconds), to allow me to tweak the equalizer?

The tools I already have:

receiver, speakers
hardware function (wave) generator
laptop computer (with sound output and mic input)
oscilloscope
measurement microphone (behringer ecm8000)
mic pre-amp mixer with analog and USB port output

I assume the soundcard in the laptop does not have a flat response curve
(both input and output), so the software should have some way to
calibrate/compensate for this.

When I google for sweep spectrum analyzer software, I found lots of hits.
Please help me narrow down the choices that make the best use of the tools I
have. Obviously, free software is preferred.

This is what live sound engineers use to "tune" the room.
Smaart
http://www.eaw.com/products/software/EAWSmaart/index.html

[WillStG]

On Mar 21, 8:09 pm, wrote:
On Mar 19, 5:54 am, "john" wrote:



Is there a program to plot frequency response of a receiver+speakers in real
time (or within a few seconds), to allow me to tweak the equalizer?

The tools I already have:

receiver, speakers
hardware function (wave) generator
laptop computer (with sound output and mic input)
oscilloscope
measurement microphone (behringer ecm8000)
mic pre-amp mixer with analog and USB port output

I assume the soundcard in the laptop does not have a flat response curve
(both input and output), so the software should have some way to
calibrate/compensate for this.

When I google for sweep spectrum analyzer software, I found lots of hits.
Please help me narrow down the choices that make the best use of the tools I
have. Obviously, free software is preferred.

This is what live sound engineers use to "tune" the room.
Smaart
http://www.eaw.com/products/software/EAWSmaart/index.html

Anyone try RoomEQWizard? It appears to be useful as a Real Time
Analysis program - and it's free too, although you have to register

http://www.hometheatershack.com/roomeq/ It's a Java app.

Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The large print giveth and the small print taketh away..." Tom Waits

[Arny Krueger]

"john" wrote in message


Is there a program to plot frequency response of a
receiver+speakers in real time (or within a few seconds),
to allow me to tweak the equalizer?
The tools I already have:

receiver, speakers
hardware function (wave) generator
laptop computer (with sound output and mic input)

Forget abut the mic input on the laptop. The line/headphone output might be
pretty fair, but your external USB audio interface will be your major tool.
Anbody who needs an inexpensive but usable USB interface can pick up a
Behringer UCA 202 for about $30.

oscilloscope
measurement microphone (behringer ecm8000)
mic pre-amp mixer with analog and USB port output

A good starting place is the freeware Audio Rightmark program, which does a
complete technical test, including frequency response, in maybe a minute or
two.

Start out by looping your audio interface, line-in to line-out.

The start adding equipment to the loop, using attenuators to bring the loop
back to unity gain. For example, you can use it to test power amps by making
yourself up a little variable attenuator out of a couple of 5K watt linear
taper potentiometers. Use that to tap the 20-50 volt output of the power amp
down to a volt or two for the input of your audio interface.

The Audio Rightmark program has a speaker testing feature that you can use
for accoustical measurements.

[Mike Rivers]

WillStG wrote:

Anyone try RoomEQWizard? It appears to be useful as a Real Time
Analysis program - and it's free too, although you have to register

I downloaded it and tried to use it. I couldn't figure out what to do
with it or
what it would do for me. It always looked like it was trying to sell me
something, as I recall. It was a few years ago.


--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[Ethan Winer[_3_]]

On Mar 22, 3:01 am, WillStG wrote:
Anyone try RoomEQWizard? It appears to be useful as a Real Time
Analysis program - and it's free too, although you have to register

Yes, I use REW all the time and it's great. It's now my main tool for
measuring rooms. Not only does the current version work very well, as
you observed it's also free. The only problem I'm aware of is it
doesn't work very well on Macs. As I understand it, the problem is the
Java runtime on Macs. Which makes sense because the same code works
very well under Windows.

--Ethan

[hank alrich]

Ethan Winer wrote:

On Mar 22, 3:01 am, WillStG wrote:
Anyone try RoomEQWizard? It appears to be useful as a Real Time
Analysis program - and it's free too, although you have to register

Yes, I use REW all the time and it's great. It's now my main tool for
measuring rooms. Not only does the current version work very well, as
you observed it's also free. The only problem I'm aware of is it
doesn't work very well on Macs. As I understand it, the problem is the
Java runtime on Macs. Which makes sense because the same code works
very well under Windows.

Contemporary Macs can boot into Windows, so there's a workaround for
Macsters who might like to use REW.

--
ha
shut up and play your guitar