# REW and firewire interface Motu-Traveller



## basementbluesboy (Dec 4, 2011)

Dear all,

I am located in Germany and I am using REW to opimize my home-recording room in order to record and mix songs.

I installed the REW on my desktop and performed some measurements, which seem to be off compared to measurements from peers. It seems that the spectrum of the low frequencies is not measured correctly. Therefore my general question: 

Does the REW work properly with Motus' firewire interface Traveller or are there any problems or difficulties with this interface

Thank you for your help.

BBB
Cologne, Germany.


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## EarlK (Jan 1, 2010)

> Does the REW work properly with Motus' firewire interface Traveller or are there any problems or difficulties with this interface



> REW doesn't work ( see input ) with FireWire based cards when used on a Mac ( PC yes, Mac no ) .

> Your best bet is to use the onboard soundcard of your Mac / you'll simply need an analog mixer to boost the mic signal up to line level for your computers line input .

> Or simply buy a cheap PC for REW use . PC is the only computing platform that REW really works "ubiquitously" on .

:sn:


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## basementbluesboy (Dec 4, 2011)

Dear EarlK,

my traveller is connected to a desktop dual core pc. So the REW should work properly with the traveller. By the way I worked three years in Toronto. I liked it. Very good classic rock radio stations.

Thank you ver much for your quick response.


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## EarlK (Jan 1, 2010)

I've been here ( currently just north of Toronto ) 35 years & counting ( so I guess, I still like it ) .

> I recommend that you read  this thread & see if you get anything out of it 

> Just substitute the model & manufacturer of your sound card whenever you see "Focusrite Saffire" .

> What I'm saying, is that a goodly majority of peoples problems ( that they think are REW based ) are actually based on a lack of functional familiarity with the on-board software that ships with their soundcard .

> Anyways, take a look at that thread first & then report back here ( some useful "check-this-first" hints within it ) .


:sn:


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## basementbluesboy (Dec 4, 2011)

Hi EarlK,

your quoted thread was about how to calibrate the soundcard. I was able to calibrate my soundcard und I had loaded that cal file when I measured my room accoustics. I posted the results in a German forum on recording and two guys mentioned that the results looked to good for an untreated room, b/c there were very few modes below 100hz, which is usually not the case. 

So basically they assumed that rhere was something wrong with the mesasurement. Now another guy looked at the measurements and he believes they are valid, but still mentioning that the room response looks pretty could for an untreted room that is why I am a little afraid that the measurements might be wrong.

bbb


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## EarlK (Jan 1, 2010)

Sorry about that bbb ! :innocent: ( I must have got up way too early this morning :dontknow: ) 

Anyhow, please post your .mdat file here as an attachement / then we can all decide if it's "too good to be true" .

*or *​
I have a smattering of high-school German rattling around in this aged brain ( schooled in the 70's ) so how about a link to the thread ?
- I can likely wade through it enough to come back & give you an opinion .


:sn:


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## basementbluesboy (Dec 4, 2011)

Hi EarlK,

I tried to send you the link, but I am not allowed to, b/c I have less than five posts. If you post your email-address I can send you an email with the link. The link has waterfalls, drawnings of the room etc.

However I have attached the mdat-file.

By the way I am married to a Canadian girl from Toronto. 

I really appreciate your help. Let me know I you can access the mdat or if it did not go through.

Now, I have to go to sleep.

By from good ole Germany.

bbb


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## basementbluesboy (Dec 4, 2011)

Hi EarlK,

did you have a chance to look at the attached measurements? Are tese valid measurements or is there something wrong with them? Let me know.

bbb back at work


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## EarlK (Jan 1, 2010)

Morning bbb,

Yep , they look valid to me .

I'll post some pics after my next coffee .


:sn:


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## basementbluesboy (Dec 4, 2011)

Hi EarlK,

that sounds good to me. If I am not mistaken when analysing the waterfall-plot I believe I have less issues with modes, than I had expected. However, I have to admitt I am not very familiar with all the other plots and the information the rew provides. But eventually, I will learn quite a bit during my project of optimizing my little mixing and recording space.

thank you very much for your help.

bbb


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## basementbluesboy (Dec 4, 2011)

Dear EarlK,

here is the link to the German forum with plots etc.:
http://recording.de/Community/Forum...ik/Raumakustik_und_Dämmung/155596/thread.html

I hope it goes through this time.

bbb


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## EarlK (Jan 1, 2010)

Hi bbb,

> Well I read that thread ( though I ended up using Google Translation since apparently not enough of my schooling has remained intact lddude: ) .
> I agree with everyone posting there that the lack of bass frequencies below 100hz is very suspicious .
> In fact, your REW responses look "gated" to me 
> ( ie ; how did you achieve a 85db signal to noise ratio in that room when your FR test data says it was done at a max level of 82 db ? ) . 
> What's your measured ambient noise level range for that room ? Surely it's not that anechoic, even down in your basement ?


> On a search, I researched the following web-page ( looking for an electronic explanation to the above paradox ) ;
> Click the pic !












> My first "go-to" reaction was to speculate that you're simply too "new" when using MOTUs' CueMix software and have mistakenly dialed in an expander/gate or a high pass filter ( somewhere ), be it either on input or on a mix output . Sadly , CueMix doesn't have an expander/gate for me to blame but it does have EQ .

> The following pic of your SC calibration puts my "User Error" suspicion to rest for now ( assuming you actually used all the same routing within CueMix for your loopback as you do for testing ) .










> Here are some screen captures that I made of ( your REW file compared to Fotos REW file ) .

(i) Both files ( yours & Fotos ) show truncated LF response . 
(ii) He has a somewhat treated HT room .
(iii) Personally, I'd move all your gear out of your room & run a whole bunch more tests ( including using other speakers ) to look for the cause of the truncated LF .
(iv) It's possible ; ( accepting a conclusion that you made a couple of minor REW setup errors, such as your SPL reference setting for one ) that your cement-walled basement room actually has a huge multiple eigenmode cancellations ( occuring almost everywhere ) amounting to one huge bass suck-out below 100 hz . That's technically possible, but that's a brutal possibility for anyone to have to embrace ( considering this is where you want to mix ) . 
> Therefore before spending huge time , effort & $$$$ on room treatment (ie; bass trapping ), I'd really want ( if I were you ) to explore other possible explanations by doing (iii) . That's all I got for now . :sn:


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## basementbluesboy (Dec 4, 2011)

Dear EarlK,

thank you for your competent analysis. This is by far the best I have read so far. My CueMix for the traveller does not have eq. I believe only the MK 828 has an built in eq feature.

For the testing I used the rew's SPL meter and the Beringer ECM mike, which I had put in the listening postion. I set rew's SPL meter to 83db and pushed the calibration button so that I hard the pink noise. With the Voltcraft SPL C-wheighted meter I matched the 83db at the listening position. Then I set the input level to approximately -20db through moving the windows sound slider und the tweak knob on the traveller. After this procedures I started to measure. The results where captured in the mdat-file, you were looking at.

However, my room is not completely untreated. A friend and I put in drywalls infront of the concrete walls and the celling. Between the drywall and the concrete wall of the room we put rockwool's sonorock. Not sure whether you have that in Canada. It is mineral wool, which is fairly good at absorbing low frequences, b/c it is fairly fluffy. On top of it we left a little bit of air between the sonorock and the bare concrete wall.

Now is it possible that the very low frequencies go through the drywall and get absorbed by the sonorock? Or should those frequences bounce back and fourth from the dry walls? 

Additionally, I only have Yamaha HS50M speakers and their frequency range goes from 55hz to 20khz. This might also contibute to the fact that the bass is so low.

As you mentioned I moved all stuff out of the room. Additionally, I put in the two front corners additional packages of sonorock, just to see what happens. The result is that the mode of approx. 150hz drops significantly, wheras the mode at around 30hz barely goes down. I just tested this b/c I would like to built super chunks to eliminate more of tha 150hz mode. After that I planned on eliminated early reflections.

Do you whant me to send you the measurements with the two chunks of sonorock in the front corners, so you can compare with the initial measurement? 

I can not get a hold of diffrent monitors, can I perform other tests to make sure that I do not have a big mode problem in that room?

I really appreciate your help with this.:T

bbb


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## EarlK (Jan 1, 2010)

You're welcome !

> What I'd like to see is a single speaker measurement executed within another room ( another room that dosn't have any cement walls ) . 
> You absolutely must get this data to be able to reference against your existing situation . 
> Until you can prove that your speakers ( with your electronics ) can give solid performance down to 55 hz, then everything you do, say & hear from others, is simply conjecture . 



bbb said:


> Now is it possible that the very low frequencies go through the drywall and get absorbed by the sonorock? Or should those frequences bounce back and fourth from the dry walls?


> They'd bounce back & worth mostly between the cement walls ( with the mineral-wool/Gyproc boundries providing attenuation during each travel/bounce ) . 

> You need some real solid advice from acousticians ( even would-be acoustians ) who populate forums such as  *GS*  as to if it is even possible for your existing wall structure to give such a Low-Q, Broad-Band LF attenuation, amounting to around 10 db . 
> Get that advice before you consider ripping out the walls or investing in more bass trapping . 
> Create the speaker reference data ( as mentioned at the beginning of this post ) before soliciting around the web for this acoustics advice .

:sn:


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## EarlK (Jan 1, 2010)

bbb said:


> As you mentioned I moved all stuff out of the room. Additionally, I put in the two front corners additional packages of sonorock, just to see what happens. The result is that the mode of approx. 150hz drops significantly, wheras the mode at around 30hz barely goes down. I just tested this b/c I would like to built super chunks to eliminate more of tha 150hz mode. After that I planned on eliminated early reflections.
> 
> Do you whant me to send you the measurements with the two chunks of sonorock in the front corners, so you can compare with the initial measurement?


> Sure, post the mdat file here & I'll take a look at it . I'm curious to see the effects of your treatments .

> Please state all the dimensions ( L x W x H in cm ) of these treatments ( superchunks, etc. ) .



> However, my room is not completely untreated. A friend and I put in drywalls infront of the concrete walls and the celling. Between the drywall and the concrete wall of the room we put rockwool's sonorock. Not sure whether you have that in Canada. It is mineral wool, which is fairly good at absorbing low frequences, b/c it is fairly fluffy. On top of it we left a little bit of air between the sonorock and the bare concrete wall.


> Hmmm, limp mass, broadband bass trap maybe ?

> Anyhow, Roxul "Safe n Sound" is available here in the GTA for us peasants to use. 

See ;




bbb said:


> For the testing I used the rew's SPL meter and the Beringer ECM mike, which I had put in the listening postion. I set rew's SPL meter to 83db and pushed the calibration button so that I hard the pink noise. With the Voltcraft SPL C-wheighted meter I matched the 83db at the listening position. Then I set the input level to approximately -20db through moving the windows sound slider und the tweak knob on the traveller. After this procedures I started to measure. The results where captured in the mdat-file, you were looking at.


> It appears to me that you did your SPL calibration in a backwards way ( not so good :nono: ) .

> Try ; Open the SPL window within REW & then select REWs SPL "calibration" button ( moving on to the next step of deciding to use fullrange pink noise as a noise type ) . Once the pink noise is running you then turn up your output signal ( using Windows mixer or your MOTUs output ) to a level that you want to measure at. Once at that (happy) level ( & with the SLM in the exact position that you will measure from using your test mic ) you read the db from the meter & then manually enter that number into the REW SPL meter window ( & then hit "Okay" ). Then close the SPL window . You're now SPL calibrated for that physical position ( for those input levels ) .


:sn:


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## basementbluesboy (Dec 4, 2011)

Dear EarlK,

as mentioned earlier attached please find the measurements with the sonorock stuffed in the front corners. Please note that the monitors are only approx 30-40cm away from the front wall. B/C I read in some basic accoustic threads that this increase the volume of the bass, espially with small speakers and small rooms. The listening position is about 1,27m away from the front wall this is about 38% of the shorte side of the wall. the exact length, width and hight of the room I will send tomorrow as I have to go to sleep now. Hoave toget up early tomorrow.

cheers and thank very much for your help.:wave::T

bbb


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## basementbluesboy (Dec 4, 2011)

Dear EarlK,

if you go to this link again:

http://recording.de/Community/Forum...ik/Raumakustik_und_Dämmung/155596/thread.html

and if you doubleclick on the pictures they should pop up almost over the whole screen. Now, go to the picture of the room, which has the headline Homestudio mit Box, if you doubleclick on it it shows you the width, length and height of the room. The listening position is the circle. The small rectangles are the monitors close to the front wall and the big rectangle is a table.

I calculated the listening position as 38% of the shorter distance to the backwall with the door. Not sure whether this correct. Maybe I should use 38% to the further distance since the backwall is splitt, b/c of the rooms L-shaped form. Or maybe I should use the average mean of the distances to calculate the listening position with 38%. I am not so sure? Do you have an idea how this is done in such a room? Or is this trial and error?

Let me know, if you can access the piture of the room. All the measures are in meter as this is the typical measure in Europe.

Hope to hearing from you soon.

bbb


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## EarlK (Jan 1, 2010)

Hi BBB ,

I think way too much is getting lost in the translation here .










> I had looked at your room layout ( & now everyone here at HTS can see it ) .



EarlK said:


> > Please state all the dimensions ( L x W x H in cm ) of these treatments ( super-chunks, etc. ) .


> I asked you to state the dimensions of the 2 pieces of super-chunk ( room-treatment ) that you placed into the corners .



EarlK said:


> > It appears to me that you did your SPL calibration in a backwards way ( not so good ) .
> 
> > Try ; this instead,,,,blab,,,,blab,,,,blab


> Have you recalibrated your SLM meter yet ?



EarlK said:


> > What I'd like to see is a single speaker measurement executed within another room ( another room that doesn't have any cement walls ) .
> 
> >* You absolutely must get this data to be able to reference against your existing situation .*
> 
> > Until you can prove that your speakers ( with your electronics ) can give solid performance down to 55 hz, then everything you do, say & hear from others, is simply conjecture ( & likely a waste of time ) .


> Have you done this yet ?



EarlK said:


> > You need some real solid advice from acousticians ( even would-be acousticians ) who populate forums such as  *GS*  to see if it is even possible for your existing wall structure to give such a Low-Q, Broad-Band LF attenuation, ( amounting to around 10 db ) .
> 
> > Get that advice before you consider ripping out the walls *or investing in more bass trapping .*
> > *Create the speaker reference data ( as mentioned at the beginning of this post )* before soliciting around the web for more acoustics advice .


> I haven't included myself in this group of experts . So this will be my last post within this thread . :wave:

> I have given you what I believe is the necessary advice so that ( once implemented by you ) you can sign-up to a good acoustics forum and get some real help for the acoustic challenges that your room represents . Just don't expect to be spoon-fed easy answers to the really difficult acoustic challenges that exist in small control rooms .

Good Luck with your quest ( & build ) !

:sn:

PS : Hopefully you already have the following 2 books / if not, buy them & keep them nearby for reference . 
You'll want to be able to state that you've at least thumbed through Rods book before you join an Acoustics Forum . ( Click the Icons ) ;


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## basementbluesboy (Dec 4, 2011)

Dear EarlK,

thank you for your help so far. Yes, I recently read through a book on accoustic treatment in a small studio. However, I am far away from being very knowlegeable with this. And no, I do not expect to be spoon fed with each and every basic. Sorry, that I have not answered your questions yet. I wanted to make the measurements this weekend, b/c I have a job during the day, too. But I guess, I do not need to post the answers to your questions in this thread, anymore, since you closed the thread.

Too bad anyhow, b/c I enjoyed mailing with you. But dont worry I will figure it out, it will just be a question of time.

Happy holidays to you and your family.:clap::bigsmile::T

bbb


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