RT60 iphone apps

[Tom Morrow]

Has anyone tried RT60 measurement tools for the iphone?  I'm curious about accuracy, whether a cheap dongle microphone is sufficient, and what stimulus you use (starter gun?)

 

I'm going to be working on a scene filmed in a real tile public bathroom, and I was thinking it would be interesting to get some measurements of how much I can reduce the RT60 with sound blankets.  More for my education really, this is not a paid project.

 

It looks like studio six has an RT60 app, and there are a few more in the app store.  I can't find the buzzispace app which looks well designed:

 

 

 

[Philip Perkins]

I guess I always wonder how well they will overcome the poor performance of the built-in iPhone mic in their calcs.  I understand that in theory they could test some iPhone mics and come up with a solution, but how consistent are those mics from batch to batch?  It generally seems like a better idea to start with a real test mic, or even some ways to plug in one of the high quality mics you might have on hand for boom work.  So far I haven't been ultra-impressed with accuracy of the iPhone audio measurement apps I have...  For a simple "how much diff" test like you propose it might be ok, as long as all you were trying to know was that there is a difference after your room treatment, by a rough amount...

 

philp

[studiomprd]

" some measurements of how much I can reduce the RT60 with sound blankets.  "

I'm with Philip, 

" about accuracy, whether a cheap dongle microphone is sufficient, "

for your stated purpose, who cares ?

[soundtrane]

<< whether a cheap dongle microphone is sufficient >>

 

Sufficient to create enough sorrow later, Mr. Morrow... 

[soundtrane]

it's strange how the "new generation" born in the post-analogue era is so enamoured by numbers, plug-ins and graphic windows. I hope it is better than what i feel (which is that only .01% of them actually LISTEN with their ears). 

[Wandering Ear]

Studio six designed an audio interface, and also a test Mic designed to plug into the bus connector so as to avoid the built in Mic.

I've never used it, so I can't testify to it's quality, but I've heard good things.

The rt60 measurements might be useful to me if I was trying to design a system of acoustical treatments for a room, but I personally have no need for that info on set. My ears tell me all I need to know about the room.

[soundmanjohn]

For any degree of accuracy, you'll need to bypass the heavily filtered and limited internal mic and the external mic socket and get an adapter that accesses your iOS device through the 30 pin accessory/charger socket. The Studio Six systems work this way and will give you a reasonably effective analyser for not very much money, although the in-app purchases are not exactly cheap. The IR add-on is £40 in the UK, the Transfer Function add-on is £60 and requires a two-input interface. The iTestMic runs at around $200, the dual input interface at around $500, so you'll need to spend a bit more than the initial $20 that app costs to get something that'll give you truly professional results. I shelled out for the SmaartTools add-on and I picked up the iTestMic at InfoComm at a special show price and I'm happy with the system as it stands. Equivalent hardware would cost you quite a bit more, although this assumes that you already own a suitable iOS device. Otherwise, you might be better seeing if you can find something used from the NTi series of hand-held analysers.

 

Regards,

 

John