# New to REW - can you use mic and hdmi



## doac00 (Jun 4, 2014)

Folks,

New to REW - do not have a SPL meter or external sound card but do have a HDX model HP laptop that probably has a good sound card within it as it's aimed at "entertainment".

Thus wondering if I could place a mic onto the mic socket and use the HDMI output into the AVR to generate the tones or if I'd still need to acquire sound card and SPL meter??

My overall aim is to try and use the REW program to assist in sub-woofer placement and then to see if I'd benifit from some form of EQ

Moved house - not overally happy with the home cinema sound, the sub is not sounding to "hot" and it maybe time to replace it but before I invest it may be prudent to check the room accoustics and see if better placement of some EQ may help - I'd need to use something like DSPeaker 8033 or a FBD as based in UK and we don't get all the same toys as you chaps in the US :-(


Chris


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## EarlK (Jan 1, 2010)

The recommended approach ( for HDMI use ) is laid out within the following e-zine article ;

-*Using the UMIK-1 and REW with HDMI output - Windows*

- This is  *the mic to buy .*

:sn:


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## Wayne A. Pflughaupt (Apr 13, 2006)

At least a couple of issues here.

For starters, the stock soundcard in your HP laptop might be up to audiophile standards, but the mic pre amp is a big question mark. And you might not be able to generate a calibration file with it in-line. And even if you can, it has no phantom power, which measurement mics require.

If you already have a mic your best option is probably to pick a soundcard from the REW Soundcard Database that is compatible with your computer. If funds are an issue, look for something used on ebay. An older soundcard might not have all the “bells and whistles” the folks who normally use them for recording purposes might desire, and as such be viewed as a “cast-off,” but one would work fine with REW.

Alternately, we recently had someone here merely use a phantom power supply for the mic and connected it to his computer with a XLR to USB converter. However, it has not been verified if this results in viable measurements. The thread is here:

http://www.hometheatershack.com/forums/rew-forum/81106-soundcard-rew-set-up.html

If you don’t already have a mic, then follow Earl’s advice and get one of the USB models. :T

Regards,
Wayne


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## doac00 (Jun 4, 2014)

Gents,

Many thx for replies.

Slight issue is I'm based in the UK and miniDSP is US based so their great USB mic is not readily accessible, unless imported.

And having a "play" with REW last night I can see I'll not be able to calibrate the set-up - I can make it work but the values are probably all way off etc..

The HDMI connection is seen in REW - I can use it as an output no problem
The Mic is the standard input on the PC - even if I got an external soundcard like the behringer uca models and a suitable mic (what would be suitable?) - how would I calibrate the set-up as I'd want to use the line-in on the soundcard but what to use the hdmi out to the AVR - hence not sure how to complete the calibration loop here - any ideas/advice please

Or just simpler to go with the soundcard line in and out and then attach to AVR via phono cable to a space input - Aux say??


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## EarlK (Jan 1, 2010)

- miniDSP is HongKong based .

They offer the best deal around for a USB connected , calibrated test mic .

:sn:


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## doac00 (Jun 4, 2014)

Whoops I stand corrected - thx

The miniDSP is something I may look into if it looks like the room needs some EQ ;-)

Right now I just want to "see" if this is a problem or if I can move my sub to rectify or if my 12 year old REL is in need of an upgrade ;-)

All advice appreciated


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## Wayne A. Pflughaupt (Apr 13, 2006)

Not sure how much more advice we can give at this point, until you get the necessary hardware to take some measurements. Or course we may have missed something that’s relevant to you, so ask away if that’s the case. :T

Regards,
Wayne


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## doac00 (Jun 4, 2014)

Wayne,

Cheers - I'm asking is there a way to use hdmi out and mic or soundcard rca in - and calibrate - i.e. make the calibration loop ???

hdmi into AVR spare hdmi front port
mic or uca222 sound card attached to a mic or SPL meter (I can get one of these off eBay readily)

So how do I "close the loop" - connect AVR speaker rca connection to the soundcard in ??

Chris


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## Wayne A. Pflughaupt (Apr 13, 2006)

The calibration loop is only needed for an outboard soundcard, not your entire audio signal chain. Have you reviewed the REW Help Files?

As far as I know, with REW you can only use your computer’s HDMI output if you’re using a USB mic. With a USB mic no soundcard calibration is needed – see the “REW connections using a USB mic” heading at the REW Cabling and Connection Basics post.

If you do not use a USB mic, an outboard soundcard will be required with any other measurement mic (such as Behringer ECM8000, Dayton EMM6). The outboard sound card will include a mic pre amp and phantom power, both of which the mic requires in order to operate. As mentioned previously, you can’t use a measurement mic with your computer’s mic input as it provides no phantom power. Check the REW Soundcard Database for a list of soundcards that will work with your operating system. Typically these are of sufficient quality that a calibration isn’t even necessary.

The REW Cabling and Connection Basics post shows common REW connection schemes and hardware (third picture diagram is most relevant)

Simply put, these are your options:

* USB mic
* Standard mic with appropriate sound card

Hope this helps!

Regards, 
Wayne


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## EarlK (Jan 1, 2010)

> <<<<SNIP>>>>As far as I know, with REW you can only use your computer’s HDMI output if you’re using a USB mic. With a USB mic no soundcard calibration is needed – see the “REW connections using a USB mic” heading at the REW Cabling and Connection Basics post.<<<<SNIP>>>>


The key to flexible (i/o) access is the use of ASIO & ASIO4ALL .

If a person sets REW to "ASIO" & then uses ASIO4ALL to cobble together an Aggregate SoundCard ( ASIO4ALL searches out all the available WDM device drivers ), that user can then access all available HDMI outputs ( while using whatever input type is currently plugged into & recognized by the computer ) .



:sn:

PS: A recent post has a good example . 

If the WDM selections found by ASIO4ALL are activated ( identifiable by the small icon showing a blue color ), they will show up as viable selections, within REW's drop-down menus within the preferences window .


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## EarlK (Jan 1, 2010)

Wayne said:


> <<<<SNIP>>>>
> The REW Cabling and Connection Basics post shows common REW connection schemes and hardware (third picture diagram is most relevant)
> 
> Simply put, these are your options:
> ...


Wayne, I didn't mean to short-circuit ( with my previous post ) your above quoted advice .

I too believe that they are the best choices .

I'll mention also, due to the ( hidden ) issues that typically arise only after the purchase ( such as a lack of calibration file ) or the "pinned meter-movement" syndrome ( due to dc off-set from the computers mic input ) something like the following can end up being a poor choice ;

 *eBay UK SPL meter *

:sn:


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## doac00 (Jun 4, 2014)

Cheers folks.

I have a Radio Shack SPL on it's way - just won it on eBay and I'll get a Behringer uca200/202 or 222 sound card to go with it and thus utilise the generic cal file for this SPL unit. 

I'm mainly using it for sub placement/test/upgrade so I plan to connect as follows:

SPL to soundcard in
Sub to soundcard out - to LFE channel of sub

Run tests for various placements - see if it may need some EQ or not - or where less is required etc..


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