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Discussion Starter · #1 ·
I am going to be embarking on a couple of speaker projects and decided on REW as a measurement tool. I have no equipment yet, so I'm looking for a recommendation on a mic and a preamp for my Windows 7/64 usb2 & 3 laptop. I think I will need a usb preamp because my laptop only has a single headphone/mic jack. Accuracy and reliability at a reasonable price is my #1 goal.

I'm computer savvy and have used RTA's in the past, but never on a pc based system.

Any feedback on hardware or links to any threads to beginners setup and getting started would be greatly appreciated.

Thx,

James
 

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I am going to be embarking on a couple of speaker projects and decided on REW as a measurement tool. I have no equipment yet, so I'm looking for a recommendation on a mic and a preamp for my Windows 7/64 usb2 & 3 laptop. I think I will need a usb preamp because my laptop only has a single headphone/mic jack. Accuracy and reliability at a reasonable price is my #1 goal.
Since your laptop has USB 2/3, you can get a USB mic (like the UMIK-1) and not need a preamp.
 

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From what I've read, I thought I needed to use a preamp since the single jack on my laptop does both input and output.
One can still get REW to output it's audio through the computers "multi-jack", while ( simultaneously ) using the UMIK-1 as the input into REW .

FYI ( slightly more complicated ), one can also use ( simultaneous with the UMIK-1 ) a simple usb based soundcard ( such as the Behringer UCA-222 ) for output from REW ( as long as the card uses Window's generic usb driver ) . I've tested this setup ( on my old laptop running XP ) using the UMIK-1 & the UCA-222 together ( using ASIO4ALL ) .

The UMIK-1 mic is recommended because it is simple to use ( plus inexpensive ) . There's an growing user base ( for these mics ), making it pretty wide-spread ( & this means there's an ever expanding web-based user group, that can act as your virtual "help file" ) .



:sn:
 

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Discussion Starter · #5 · (Edited)
One can still get REW to output it's audio through the computers "multi-jack", while ( simultaneously ) using the UMIK-1 as the input into REW .

FYI ( slightly more complicated ), one can also use ( simultaneous with the UMIK-1 ) a simple usb based soundcard ( such as the Behringer UCA-222 ) for output from REW ( as long as the card uses Window's generic usb driver ) . I've tested this setup ( on my old laptop running XP ) using the UMIK-1 & the UCA-222 together ( using ASIO4ALL ) .

The UMIK-1 mic is recommended because it is simple to use ( plus inexpensive ) . There's an growing user base ( for these mics ), making it pretty wide-spread ( & this means there's an ever expanding web-based user group, that can act as your virtual "help file" ) .



:sn:
That's great, I've always been a fan of K.I.S.S., and the UMIK-1 fits the simple part.

I saw a chart somewhere that showed I needed an output to get signal to my stereo's preamp, an input for the SPL meter and an input for the measurement mic.

What SPL meter do you recommend? My understanding of it's use is to establish a SPL baseline for the measurement mic, right? Once you store this reference do you still need to use the SPL meter?
 

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That's great, I've always been a fan of K.I.S.S., and the UMIK-1 fits the simple part.
Agreed.

I saw a chart somewhere that showed I needed an output to get signal to my stereo's preamp, an input for the SPL meter and an input for the measurement mic.
Nope. You need an input for the mic (USB) and an output for the stereo system (headphone jack) and you do not need the SPL meter if the mic's calibration comes with sensitivity info.

What SPL meter do you recommend? My understanding of it's use is to establish a SPL baseline for the measurement mic, right? Once you store this reference do you still need to use the SPL meter?
See above.
 

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Just purchased the UMIK-1 from Cross Spectrum. Now, I need to figure out what else I will need.

Maybe a mic stand????

How long of a cable does it come with?
It appears to me that maybe you've rushed into this purchase without completing your homework/research .

For instance, if you're intending on putting together a hardware system that can collect the necessary data for crossover design ( & hand it off to a sophisticated network modeling program ), then the UMIK-1 is not the unit to get . You need a 2-chnl soundcard ( for that ) because you'll need to dedicate one as a timing channel .

Instead, you'll need something like the calibrated Dayton EMM-6 mic // coupled with a 2-chnl preamp Soundcard ( such as the Focusrite 2i2 or Tascam US-122mkII ) .

:sn:
 

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Discussion Starter · #11 ·
It appears to me that maybe you've rushed into this purchase without completing your homework/research .

For instance, if you're intending on putting together a hardware system that can collect the necessary data for crossover design ( & hand it off to a sophisticated network modeling program ), then the UMIK-1 is not the unit to get . You need a 2-chnl soundcard ( for that ) because you'll need to dedicate one as a timing channel .

Instead, you'll need something like the calibrated Dayton EMM-6 mic // coupled with a 2-chnl preamp Soundcard ( such as the Focusrite 2i2 or Tascam US-122mkII ) .

:sn:
Thanks EarlK.

Just sent CS a message to change my order to the Dayton EMM-6 Premium Plus. Hopefully they haven't shipped it yet. You are exactly right, my first project will be setting up midrange and high frequency horns on my 105db Frazier Super Texan bass horns.

Any preference on which of the 2 sound cards?
 

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Both of those soundcards are nice solid units ( the 122 is the more "weighty" of the two ) . Both are well built, giving a nice feeling of "quality", when turning a knob for instance .

The Tascam is a bit cheaper, while the Focusrite has better input metering ( actually, like most cards in this price range, the Tascam has no input metering ) .

I do own both ( well actually, I have the Tascam US-144, to be a bit more exact, which I got it for it's midi capability ) .

I guess I will give the edge to the Focusrite simply because of the input metering . ( It's very easy to see when a person should back-off the input gain > due to the metering turning red ) .

:sn:
 

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If I remember correctly the midi function is necessary to use the auto eq programming in Minidsp???
No, it's useful if a person wants to Auto-Configure the PEQ filters found within some of the Behringer EQ units ( that REW specifically supports ) .

Install REW , open the EQ window , then click on top right tab to see exactly which Behringer models are supported .
- FYI, you'll see a bunch of EQ's listed from other manufacturers, but they don't have midi connectivity .

:sn:
 

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Discussion Starter · #15 ·
Thanks for the help EarlK. Hope you're around when it comes time to fire it up and test some drivers.

I got a shipping notification from Herb @ Cross Spectrum on the EMM-6 Premium Plus. Should have it in a couple of days.

I just ordered the Focusrite 2i2 from BH Photo too.
 

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If I can piggyback on this discussion of bang for the buck REW hardware, it seems that I went for the "simple" setup and bought a USB UMM-6 mic and successfully got REW up and running / measuring with my HDMI / USB laptop. BUT... what I did not understand when I purchased this mic is that this type of setup will not let me use loopback to set delays and also objectively align the subs to the mains. So what hardware do I need for this? I assume the UMIK-1 and some external soundcard? Or a mic preamp too? All of the above? Thanks for all help!
 

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If I can piggyback on this discussion of bang for the buck REW hardware, it seems that I went for the "simple" setup and bought a USB UMM-6 mic and successfully got REW up and running / measuring with my HDMI / USB laptop. BUT... what I did not understand when I purchased this mic is that this type of setup will not let me use loopback to set delays and also objectively align the subs to the mains. So what hardware do I need for this? I assume the UMIK-1 and some external soundcard? Or a mic preamp too? All of the above? Thanks for all help!

Either SoundCard ( SC ) mentioned previously will suffice .

Both of those soundcards have builtin mic pre-amps & can deliver 48V phantom power ( needed for all test mics ) .

One then needs a mic such as the EMM-6 from CSL .


Since you've already jumped the gun once ( so before spending more $$ ), I suggest that you read a whack of threads on the subject of aligning subs with mains ( use this forums search engine to find them ) .

Also, look for what ( HTS member )"jtalden" has to say about alignments ( I consider him the site expert on this subject ) .
- I believe that in the past he's stated that achieving acceptable ( sub to mains ) alignment doesn't dictate a two channel soundcard ( though all the following examples do employ a timing channel ).

Simply using the RTA window ( while playing back PN Pink Noise from the generator ) & then turning the "phase knob" on a powered sub ( while watching for the best "combining" in the crossover region ), is good enough for many .

Here's A thread ( that obviously used a timing channel ) .

And Another

One More !

A Favourite !

Last One !

:sn:
 

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Thanks for the links. I am working through them. Although at this point I think I am more confused that when I started. Lots of them start of making me think they are going to simply say "click these settings and take this measurement" but by the end of the instructions I don't even know what I am trying to measure. Ugh.

Some of them get into time alignment of drivers within a cabinet so that may be where I get a little off. I just want to align my subs with each other, set objectively proper distances for my main speakers, and then time align the single sub channel (the sum of the 4 subs) to the center channel speaker.
 

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I just want to align my subs with each other, set objectively proper distances for my main speakers, and then time align the single sub channel (the sum of the 4 subs) to the center channel speaker.
Half the battle is knowing what you want to do! With 4 subs there are likely several good approaches to achieve smooth bass response. My experience is with time aligning the SW so they are:
1. Working together
2. Time aligned as a group to best match the main speakers.

I think of these as 2 separate tasks. I suggest you address one at a time.

How #1 is approached is very dependent on the equipment used to adjust delays and how much work/learning you want to do. If you want some help or direction from me, please provide some background on your equipment and setup.

You also mentioned aligning the mains as well. That is also possible in a very technical and obsessive way, but it is perfectly adequate to just set the mains timing per the measured distance unless there is reason that the electrical delay is different between them as maybe in some HTPC setups using FIR filters?
 

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Half the battle is knowing what you want to do! With 4 subs there are likely several good approaches to achieve smooth bass response. My experience is with time aligning the SW so they are:
1. Working together
2. Time aligned as a group to best match the main speakers.

I think of these as 2 separate tasks. I suggest you address one at a time.

How #1 is approached is very dependent on the equipment used to adjust delays and how much work/learning you want to do. If you want some help or direction from me, please provide some background on your equipment and setup.

You also mentioned aligning the mains as well. That is also possible in a very technical and obsessive way, but it is perfectly adequate to just set the mains timing per the measured distance unless there is reason that the electrical delay is different between them as maybe in some HTPC setups using FIR filters?
Thank you very much for the offer.
Here is the pertinent equipment:

Three Seaton Catalyst 12c mains, Four Seaton Submersive F2 subwoofers, Triad Bronze L/C/R surrounds, Marantz AV8801 (not using Audyssey), Emotiva UPA-2, UPA-200,

Xilica XP-2040 for sub EQ

I have attached a diagram of my room with sub locations (not changeable).

Regarding electrical delay, my LCR speakers and all subs have a DSP crossover in them so their distances will differ from measured. The surround are not active surrounds so they can be measured.

If it is useful here is also an MDAT file. The small description in the left box for each measurement corresponds to which sub it is and how much delay is added in the Xilica. I.e "right 9.75ms" is the right side sub with 9.75ms of delay.

Thanks again!
 

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