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Author Topic: Question about SLM capability  (Read 6516 times)

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PeterHa

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Question about SLM capability
« on: November 06, 2009, 02:13:33 PM »
I'm interested in buying SignalScope Pro for iPhone, but I'd like to check about its capability as a sound level meter before purchasing.

The website indicates that the fractional-octave-band analyzer mode includes measurement of frequency-weighted time-averaged sound level (eg L_Aeq) and maximum and peak levels, but I couldn't see where these are displayed and controlled on the example screenshot. Could you show a screenshot of these facilities, please?

Does the app indicate C-weighted peak sound level?

What are the minimum and maximum frequencies for the 'flat' frequency weighting? Does it cover 10 Hz to 20 kHz as in the IEC 61672-1 specification for frequency weighting Z?

My personal preference would be to buy your SoundMeter app and then use in-app purchasing to upgrade later to SignalScope Pro. Is that possible, or planned?

Thanks in advance,
Peter

FaberAST

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Re: Question about SLM capability
« Reply #1 on: November 09, 2009, 10:26:39 AM »
SignalScope Pro's octave analyzer performs the same measurements as SoundMeter does, but it does it for each octave or 1/3-octave band. Levels are displayed graphically, (or numerically, one frequency band at a time, with a cursor). It can display an overall level (numerically), but only the current overall level is displayed (not peak or max).

Quote
Does the app indicate C-weighted peak sound level?
It does for each octave or 1/3-octave band.

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What are the minimum and maximum frequencies for the 'flat' frequency weighting? Does it cover 10 Hz to 20 kHz as in the IEC 61672-1 specification for frequency weighting Z?
It depends on the hardware used. For some line-input accessories connected to the iPhone's dock connector, you should be able to utilize the full 10 Hz to 20 kHz range, within the Class 1 tolerances specified in IEC 61672-1. However, current iPhone and iPod touch devices roll off low frequencies for built-in microphone and headset input signals. You may be interested in taking a look at the frequency response plots on the blog:
iPhone Dock and Headset IO Frequency Response
iPhone Line Input Frequency Response Comparison
iPhone Microphone Frequency Response Comparison

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My personal preference would be to buy your SoundMeter app and then use in-app purchasing to upgrade later to SignalScope Pro. Is that possible, or planned?
I suspect that, over time, you may see a gradual convergence of our iPhone apps, so that functionality in one may be employed in another, via in-app purchase. However, this convergence will remain somewhat limited. For example, I expect that SoundMeter will remain focused on sound. SignalScope Pro, on the other hand, is geared toward measurements of electronics and vibration, in addition to sound.

Ben

PeterHa

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Re: Question about SLM capability
« Reply #2 on: November 20, 2009, 06:38:34 PM »
Hi Ben,

Thanks for your clear and informative response. On that basis, I'm going to go ahead and purchase SoundMeter.

I would have purchased SignalScope Pro (which looks very powerful) if it had overall C-weighted peak sound level, instead of just in fractional-octave bands. Hope you might find that a potential feature for a future version of SignalScope Pro.

Peter