Quick understanding check, please.

[Hermit]

Just asking the simple and obvious to be sure I get the basic idea, while I buy everything to get started.

1 - The laptop analyzer can stand alone. With laptop, REW, Behringer, RS meter, and soundcard I can test room acoustics (so I can adjust speaker position and room panels before setting the equalizer).
2 - Using the Behringer eliminates the RS meter connection, but meter is still used to set dB.
3 - An equalizer is not required for using REW, so connections shown in sticky, reflect having an EQ.

?... thanks... Don

[brucek]

1 - Yep

2 - Don't understand what you mean...

3 - Yep. I don't know what sticky you're referring to, but REW certainly works without an equalizer being in the circuit..

brucek

[Hermit]

Thanks...

Most important question answered and others can be inferred.

The sticky is the last one in this forum, and leads to a graphic where the RS meter is connected to the input of the laptop, so the meter can provide a signal. I understand the Behringer will be the signal source when it is connected, and the RS meter only used to set level.

I tried to put in a link but messed something up... I will study and learn how to be a better user.

I'm excited, but its a steep learning curve. Purchased and tested the Behringer with an automated receiver calibration. SB Live card is on its way. Plan to practice on existing set up, and get serious when my new mains and sub EQ are delivered. Just a bit concerned I have misunderstood the "how-to" pages and I will make wrong buying choices.

Great Holidays to All... Don

[brucek]

the RS meter is connected to the input of the laptop, so the meter can provide a signal. I understand the Behringer will be the signal source when it is connected, and the RS meter only used to set level.

The RS meter is connected to the line-in of a soundcard that connects to the laptop (or a PC).

I still can't understand what you mean by the statement that the Behringer will be the signal source? What's a Behringer? Can you explain what you mean?

Is the picture you're referring to the one below?

REW is a software tool that outputs a sweep from a PC into your stereo system. The system subwoofer plays the signal that a microphone (RS meter) picks up and sends to the PC to be analyzed. The software then recommends filters to enter into an equalizer (if you have one). That's it...........



RoomEQ_Wizard_WIRING_DIAGRAM.jpg


brucek

[Hermit]

Sorry Bruce...

Didn't realize how bad my understanding is... think I better find time to read a lot more, before I talk.

I meant a Behringer 8000 "microphone"... thought it was so commonly used for analysis that more words were unnecessary. Also I guessed that any device that provides a signal to an input would be called a source... and so I dubbed the Behringer a source. The thread I spoke of had photographs of how the operator connected his Radio Shack SPL meter to the soundcard, and in turn to his subwoofer equalizer. Your diagram shows the SPL meter connected to the laptop and mentions using an alternative microphone... which is my plan.

Im a bit off balance at how badly I am mangling my communication and realize I am in dire need of hands on practice. Think I need to pause my question, until I can hook up my equipment, and see what everyone is talking about first hand. Also will make more time to read thru threads so I can better understand what I am trying to say.

Thanks... Don duh:

[clubfoot]

Yes you can use the 8000 or RS for taking measurements with the appropriate calibration file loaded and they are very, very close for sub measurements. If you need to measure higher then use an 8000.

[Hermit]

Yep clubfoot...

I will be testing full range with the Behringer mic. With my extended range tweeters and SVS PC-Ultra sub I expect to reproduce from 20 H z to 40 KHz. Factor in my small room (15x11x7) and I expect to be "very" challenged. I've been working on the HT stuff for 3 years now and tried to apply lots of theoretical design from the Master Handbook of Acoustics and lots of tech articles from various websites and forums. HT is such a complex discipline... which makes it fun for me... I like the challenge.

The major issue now is for me to have high quality, quantatative data. My best friend is a musician with a little technical experience. We have spent lots of time building and adjusting my stuff, over the last year and a half, and we hear a "tremendous" improvement in quality. Now we are to the point that the changes we make are inherently subtle, because the general quality of the HT is so much better. Sometimes what seems like an improvement this week, doesn't seem that way next week.

Hense the step up to digital analysis and subwoofer equalization. First thing I am refining is my existing room and system response... just to figure out what all the research and guesswork over the last 3 years adds up to. I'll be graphing all the experiments and trying to get the best performace from my physical room acoustics. Then add the new mains and equalizer and see if I can amaze myself and friends... fingers crossed...

Enough rambling for now and back to building my rear, high-corner absorbers... .

Thanks to all... and have a good weekend... Don

p.s... To the powder hounds out there - Ive got a foot of snow on my valley driveway, with 3 to 5 feet "fresh powder" at the mountain extremes... time to get back out on the trails...

[brucek]

I meant a Behringer 8000 "microphone"... thought it was so commonly used for analysis that more words were unnecessary.

Ahh OK, my bad. Yeah, the ECM8000 is used for measuring, while the SPL meter in that case would be used only once during calibration of the SPL level setting at the listening position. The Check Levels routine is started and your receiver is adjusted to output 75dB at the listening position. This 75dB is set using the Radio Shack meter (handheld or whatever) without any connections - then the meter is put away. Then while still running Check Levels, the ECM8000's preamp and laptops soundcards input level controls are set to appease REW. Then the REW SPL meter is adjusted to match the 75dB (by running Calibrate SPL routine), thereby calibrating REW to track an actual SPL level set with the RS meter.

All that verbiage takes 100 times longer to write down than actually do the job...

brucek

[Hermit]

... and its always harder when it involves a new student... like myself... . All-in-all, my first questions are answered and I am probably barking up the "right" tree.

Bad news is I can see the set up and prep is quite complex and essential... and its going to cost me a few braincells to understand how to do it well enough. (shouldn't have used so many up )

Its a "REALLY" good thing I enjoy learning and challenges so much... .

And I'm sure I will have a few more questions when I try to run the first pass on my HT....

Back to work... lots to get ready... thanks... cheers... Don

[Hermit]

To everyone who scratched their heads over my questions... SORRY...

Aaaaahhhhh... "MY BAD" ?

Just played with REW to see if my laptop's soundcard would work, since it has line in and out. My ignorance of REW was quickly evident.

Before joining here I skimmed the instructions of another analysis program. I believe it discussed the technician manually playing prerecorded test and reference tones, while the program displayed the acoustic effects on these tones.

I did not understand that REW is a fully automated system that generates its own test tones, and marches itself thru the analysis (pretty much like my Pioneer receiver, but better). I was only expecting REW to provide real-time analysis, so I could figure out adjustments for system acoustics.

I now understand the REW has to be connected to a processor so it can generate its own test tones, as needed.

Both very cool and more complicated than I was expecting... g'night... Don

p.s... the connections photos, I spoke of previously, are in the REW online instructions files

[DrWho]

Hermit wrote:

With my extended range tweeters and SVS PC-Ultra sub I expect to reproduce from 20 H z to 40 KHz.

The highest frequency you'll be able to measure will be half the sampling rate of your soundcard. Most soundcards are 48kHz, so you'll only be able to measure up to 24kHz.

If you're using CDs for your source material, then the highest possible frequency to be recorded will be 22.05kHz. It is a brick wall physical limitation of digital systems (it is impossible for higher frequencies to be generated).

[Hermit]

Thanks Doc...

I was wondering what the frequency limits of the test were, and hadn't found an answer yet. The relationship between sampling frequency and test limits is especially interesting. I'm only paying attention up to 20.000 Hz, since I understand that is pretty much a limit for all but the most acceptionally gifted listeners... and my old ears are probably only good to 16,000... ;-( .

I included the overkill response info in case it might be useful to the more experienced people here - and they could shed light on what I don't know or understand or even know to ask. As for the super-tweeters... I bought them for 3 reasons - They were such a great price I thought it best to buy them now... I enjoy experimenting with "rocket"-science kind of toys... and the ERTs support lower frequencies, since they are crossed over at 12 or 15 kHz, selectable (if I remember right). Even using a SACD I believe the original "master" recording is also an issue, since you can't duplicate what wasn't recorded in the first place.

I think the extra support for higher frequencies will be worth the price, and I hope it will help to create the spine-tingling experience I want.

Thanks again... Best Wishes to All... the Hermit

[Tom2000]

Hi,

Ahh OK, my bad. Yeah, the ECM8000 is used for measuring, while the SPL meter in that case would be used only once during calibration of the SPL level setting at the listening position. The Check Levels routine is started and your receiver is adjusted to output 75dB at the listening position. This 75dB is set using the Radio Shack meter (handheld or whatever) without any connections - then the meter is put away. Then while still running Check Levels, the ECM8000's preamp and laptops soundcards input level controls are set to appease REW. Then the REW SPL meter is adjusted to match the 75dB (by running Calibrate SPL routine), thereby calibrating REW to track an actual SPL level set with the RS meter.

All that verbiage takes 100 times longer to write down than actually do the job...

I am a newbie here, and ran into this thread. It does answer some of my question regarding to the set up and procedure. Great!

--Tom