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Documents Folder Title Following special characters are not supported: \ / ? % * : | " < > Privacy Public All Members My Connections Only Me Cancel Create 000130.html 4 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>John Woodgate</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CGcO8NvDgZWbSFwr5%40jmwa.demon.co.uk%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">jmw at jmwa.demon.co.uk </A><BR> <I>Sun Oct 27 13:15:44 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000129.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000131.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#130">[ date ]</a> <a href="thread.html#130">[ thread ]</a> <a href="subject.html#130">[ subject ]</a> <a href="author.html#130">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">2498EF26-E564-487B-A768-0C110D82A366 at petermapp.com</A>>, dated Sun, 27 Oct 2013, Peter Mapp <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> writes: ><i>I have 3 software versions of an MLS signal. Can verify that filtering </I>><i>affects the crest factor _ though don't have results to hand. I could </I>><i>re measure with a known pink filter if this would assist. </I> If you have .wav files (with at least one full sequence if not too huge; there is one with a 40 minute recurrence period in the literature), please send them to me. If they are huge, can you please send .wav files on a CD? This, of course, in addition to any measurements you conduct. One thing isn't clear; do you have the 'known pink filter' or do you want the circuit of mine? -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk If dictionaries were correct, we would only need one, because they would all give the same information. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000129.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000131.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#130">[ date ]</a> <a href="thread.html#130">[ thread ]</a> <a href="subject.html#130">[ subject ]</a> <a href="author.html#130">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000131.html 5 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>Peter Mapp</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3C5C1FA761-3412-451D-87E8-BA5C134FEF70%40petermapp.com%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">peter at petermapp.com </A><BR> <I>Sun Oct 27 13:52:57 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000130.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000132.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#131">[ date ]</a> <a href="thread.html#131">[ thread ]</a> <a href="subject.html#131">[ subject ]</a> <a href="author.html#131">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Will do when back in uk. Two of the software versions include ability to pink shape the signal. I have B&K filter for other expt or ( it might be interesting to also use your filter but as you already have & my time at the moment is a little limited, perhaps you could do that - at least in the first instance. Perhaps we should explain to Thomas that we are not intending to use the IR potential of MLS, but merely to use as a consistent & repeatable signal signal instead of pseudorandom pink noise. Rgs Peter Sent from my iPhone On 27 Oct 2013, at 19:30, "John Woodgate" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A>> wrote: ><i> In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">2498EF26-E564-487B-A768-0C110D82A366 at petermapp.com</A>>, dated Sun, 27 Oct 2013, Peter Mapp <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> writes: </I>><i> </I>>><i> I have 3 software versions of an MLS signal. Can verify that filtering affects the crest factor _ though don't have results to hand. I could re measure with a known pink filter if this would assist. </I>><i> </I>><i> If you have .wav files (with at least one full sequence if not too huge; there is one with a 40 minute recurrence period in the literature), please send them to me. If they are huge, can you please send .wav files on a CD? This, of course, in addition to any measurements you conduct. </I>><i> </I>><i> One thing isn't clear; do you have the 'known pink filter' or do you want the circuit of mine? </I>><i> -- </I>><i> OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk </I>><i> If dictionaries were correct, we would only need one, because they would all </I>><i> give the same information. </I>><i> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </I>><i> _______________________________________________ </I>><i> SC-04-08 mailing list </I>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I>><i> </I>><i> </I> </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000130.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000132.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#131">[ date ]</a> <a href="thread.html#131">[ thread ]</a> <a href="subject.html#131">[ subject ]</a> <a href="author.html#131">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000132.html 3 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>John Woodgate</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3Ctcw2toEYDXbSFw%24%2B%40jmwa.demon.co.uk%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">jmw at jmwa.demon.co.uk </A><BR> <I>Sun Oct 27 14:00:24 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000131.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000133.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#132">[ date ]</a> <a href="thread.html#132">[ thread ]</a> <a href="subject.html#132">[ subject ]</a> <a href="author.html#132">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">5C1FA761-3412-451D-87E8-BA5C134FEF70 at petermapp.com</A>>, dated Sun, 27 Oct 2013, Peter Mapp <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> writes: ><i> </I>><i>Perhaps we should explain to Thomas that we are not intending to use </I>><i>the IR potential of MLS, </I> Indeed. ><i>but merely to use as a consistent & repeatable signal signal instead </I>><i>of pseudorandom pink noise. </I> I think you mean '....instead of other sorts of noise, e.g. from avalanche diodes.' -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk If dictionaries were correct, we would only need one, because they would all give the same information. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000131.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000133.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#132">[ date ]</a> <a href="thread.html#132">[ thread ]</a> <a href="subject.html#132">[ subject ]</a> <a href="author.html#132">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000133.html 7 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>Thomas Lagö</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CBLU0-SMTP240076301248292A1FA0E92CC0F0%40phx.gbl%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">thomaslago at msn.com </A><BR> <I>Sun Oct 27 14:20:27 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000132.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000145.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#133">[ date ]</a> <a href="thread.html#133">[ thread ]</a> <a href="subject.html#133">[ subject ]</a> <a href="author.html#133">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Dear Peter, Peter, Thanks for your prompt response. Your questions and remarks are tricky and clever. I will try to handle part of it right now. An MLS with a sync signal will NOT behave like a random source since it is a deterministic signal. Without a sync, an MLS behaves "random" and then many of your comments are valid. WITH a sync signal, the length must be longer than the impulse response of interested and together with the bandwidth needed, this sets the clock frequency and hence the length as well. A filtering can easily become "inherent" in the sequence since both the LMS and the filtering follows an FIR filter structure. I have proven this in my designs. For a synchronised signal and a linear system, this becomes less important but crest factor and "out of band" signals will change by the filtering. The basic MLS signal has a "sinc" shape in frequency domain. For LTI systems, the output response is NOT related to the input signal, given that we cover bandwidth and dynamic range properly. For a non-synchronised signal, we enter a completely different domain where we are trying to "emulate" a random signal. Then, length and filtering has a completely different meaning. We need to define how "linear" we are. Do we assume that distortion is reasonably small or not? If not, a random signal will give an LMS estimate and THEN all statistical parameters WILL impact the results since the input signal impacts the result for a non-linear systems but does not for a linear system. Did I manage to explain the difference in signal generator approaches in regards to linear and non-linear systems? Do we assume a synchronised or non-synchronized MLS? For speakers, I always use a synchronized MLS! I might compare with a "random" but my MLS signal is my reference! Best regards, Thomas Lagö On Oct 27, 2013, at 8:52 PM, "Peter Mapp" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> wrote: ><i> Will do when back in uk. Two of the software versions include ability to pink shape the signal. I have B&K filter for other expt or ( it might be interesting to also use your filter but as you already have & my time at the moment is a little limited, perhaps you could do that - at least in the first instance. </I>><i> </I>><i> Perhaps we should explain to Thomas that we are not intending to use the IR potential of MLS, but merely to use as a consistent & repeatable signal signal instead of pseudorandom pink noise. </I>><i> </I>><i> Rgs </I>><i> </I>><i> Peter </I>><i> </I>><i> Sent from my iPhone </I>><i> </I>><i> On 27 Oct 2013, at 19:30, "John Woodgate" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A>> wrote: </I>><i> </I>>><i> In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">2498EF26-E564-487B-A768-0C110D82A366 at petermapp.com</A>>, dated Sun, 27 Oct 2013, Peter Mapp <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> writes: </I>>><i> </I>>>><i> I have 3 software versions of an MLS signal. Can verify that filtering affects the crest factor _ though don't have results to hand. I could re measure with a known pink filter if this would assist. </I>>><i> </I>>><i> If you have .wav files (with at least one full sequence if not too huge; there is one with a 40 minute recurrence period in the literature), please send them to me. If they are huge, can you please send .wav files on a CD? This, of course, in addition to any measurements you conduct. </I>>><i> </I>>><i> One thing isn't clear; do you have the 'known pink filter' or do you want the circuit of mine? </I>>><i> -- </I>>><i> OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk </I>>><i> If dictionaries were correct, we would only need one, because they would all </I>>><i> give the same information. </I>>><i> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </I>>><i> _______________________________________________ </I>>><i> SC-04-08 mailing list </I>>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I>>><i> </I>>><i> </I>><i> </I>><i> _______________________________________________ </I>><i> SC-04-08 mailing list </I>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I>><i> </I> </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000132.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000145.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#133">[ date ]</a> <a href="thread.html#133">[ thread ]</a> <a href="subject.html#133">[ subject ]</a> <a href="author.html#133">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000134.html 9 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>Pete Soper</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CF36D8618-9ACA-4BDB-8035-299B17D43EB7%40meyersound.com%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">psoper at meyersound.com </A><BR> <I>Sun Oct 27 15:56:08 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000150.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000137.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#134">[ date ]</a> <a href="thread.html#134">[ thread ]</a> <a href="subject.html#134">[ subject ]</a> <a href="author.html#134">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Thomas (and anyone else who may have missed this before) the objective of this project is to define and create a calibration reference pink signal in an effort to eliminate differences in pink noise signal for purposes of level calibration and 1/3 octave RTA frequency response evaluation, nothing more. In the situations it is assumed that the system is LTI for all intents and purposes (despite the fact that there are no such guarantees with too many sound systems). I hope that helps constrain the needs of the signal being discussed somewhat. Sent from my iPhone ><i> On Oct 27, 2013, at 1:20 PM, "Thomas Lagö" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">thomaslago at msn.com</A>> wrote: </I>><i> </I>><i> Dear Peter, </I>><i> </I>><i> Peter, </I>><i> </I>><i> Thanks for your prompt response. Your questions and remarks are tricky and clever. I will try to handle part of it right now. </I>><i> </I>><i> An MLS with a sync signal will NOT behave like a random source since it is a deterministic signal. Without a sync, an MLS behaves "random" and then many of your comments are valid. WITH a sync signal, the length must be longer than the impulse response of interested and together with the bandwidth needed, this sets the clock frequency and hence the length as well. A filtering can easily become "inherent" in the sequence since both the LMS and the filtering follows an FIR filter structure. I have proven this in my designs. For a synchronised signal and a linear system, this becomes less important but crest factor and "out of band" signals will change by the filtering. The basic MLS signal has a "sinc" shape in frequency domain. For LTI systems, the output response is NOT related to the input signal, given that we cover bandwidth and dynamic range properly. </I>><i> </I>><i> For a non-synchronised signal, we enter a completely different domain where we are trying to "emulate" a random signal. Then, length and filtering has a completely different meaning. </I>><i> </I>><i> We need to define how "linear" we are. Do we assume that distortion is reasonably small or not? If not, a random signal will give an LMS estimate and THEN all statistical parameters WILL impact the results since the input signal impacts the result for a non-linear systems but does not for a linear system. </I>><i> </I>><i> Did I manage to explain the difference in signal generator approaches in regards to linear and non-linear systems? Do we assume a synchronised or non-synchronized MLS? For speakers, I always use a synchronized MLS! I might compare with a "random" but my MLS signal is my reference! </I>><i> </I>><i> Best regards, </I>><i> Thomas Lagö </I>><i> </I>>><i> On Oct 27, 2013, at 8:52 PM, "Peter Mapp" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> wrote: </I>>><i> </I>>><i> Will do when back in uk. Two of the software versions include ability to pink shape the signal. I have B&K filter for other expt or ( it might be interesting to also use your filter but as you already have & my time at the moment is a little limited, perhaps you could do that - at least in the first instance. </I>>><i> </I>>><i> Perhaps we should explain to Thomas that we are not intending to use the IR potential of MLS, but merely to use as a consistent & repeatable signal signal instead of pseudorandom pink noise. </I>>><i> </I>>><i> Rgs </I>>><i> </I>>><i> Peter </I>>><i> </I>>><i> Sent from my iPhone </I>>><i> </I>>>><i> On 27 Oct 2013, at 19:30, "John Woodgate" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A>> wrote: </I>>>><i> </I>>>><i> In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">2498EF26-E564-487B-A768-0C110D82A366 at petermapp.com</A>>, dated Sun, 27 Oct 2013, Peter Mapp <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> writes: </I>>>><i> </I>>>>><i> I have 3 software versions of an MLS signal. Can verify that filtering affects the crest factor _ though don't have results to hand. I could re measure with a known pink filter if this would assist. </I>>>><i> </I>>>><i> If you have .wav files (with at least one full sequence if not too huge; there is one with a 40 minute recurrence period in the literature), please send them to me. If they are huge, can you please send .wav files on a CD? This, of course, in addition to any measurements you conduct. </I>>>><i> </I>>>><i> One thing isn't clear; do you have the 'known pink filter' or do you want the circuit of mine? </I>>>><i> -- </I>>>><i> OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk </I>>>><i> If dictionaries were correct, we would only need one, because they would all </I>>>><i> give the same information. </I>>>><i> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </I>>>><i> _______________________________________________ </I>>>><i> SC-04-08 mailing list </I>>>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>>>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I>>><i> </I>>><i> _______________________________________________ </I>>><i> SC-04-08 mailing list </I>>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I>><i> </I>><i> _______________________________________________ </I>><i> SC-04-08 mailing list </I>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I> NOTICE: This email may contain confidential information. Please see <A HREF="http://www.meyersound.com/confidential/">http://www.meyersound.com/confidential/</A> for our complete policy. </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000150.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000137.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#134">[ date ]</a> <a href="thread.html#134">[ thread ]</a> <a href="subject.html#134">[ subject ]</a> <a href="author.html#134">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000135.html 12 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>david murphy</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CDC98EF6CF2F08F40AA5AA23B3509EDA973C6E21235%40KRIX-DC.Krix.local%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">dmurphy at krix.com.au </A><BR> <I>Sun Oct 27 16:17:13 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000141.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000136.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#135">[ date ]</a> <a href="thread.html#135">[ thread ]</a> <a href="subject.html#135">[ subject ]</a> <a href="author.html#135">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Hi all, I seem to remember that, at the C'tee meeting in NYC, we were initially talking about a 'new' pink noise source, one which had defined characteristics, as compared to the melange of pink noise signals currently out and about. Ben Kok was mentioning a duration of about 1 second, saying that if the stimulus and measurement times were matched that was a good thing. From memory, he also said that if the measurement hadn't settled then the sequence could be repeated until a satisfactory (unchanging) result was noted. A cinema I measured recently had an EDT-10 from MLSSA of the order of a couple of seconds below 50Hz, but was very short in the MF and HF. If we also have in the back of our minds that we are considering general electro-acoustic measurements for other venues (eg worship houses) then whatever we come up with should be able to be used in those kinds of environments as well. Perhaps it is possible to devise a couple of shaped pseudo random shaped sequences, a short and a long, which could be used as a pink noise source with a RTA, or with sync, used as a MLS and thus obtain a frequency response via the impulse response, but one which could be time windowed to discriminate between early (direct) sound and later sound. There will be variations in the statistics of the signal by the time it gets through the loudspeakers and back to the microphone because of the unknown number and type of high pass filters in the B Chain, not the least of which is the vented boxes almost universally used for the LF! At a workshop at AES135 NY, I presented and compared measurement results from MLSSA and from a pink noise RTA, and found that there was reasonable consistency at MF and HF, but the LF frequency response measured with MLSSA was strongly dependent on the windowing length - the longer the window the more variations - no surprise. My dilemma was deciding on what I should set to be the correct SPL level for the LF - the long term RTA from pink noise, or a frequency response from an arbitrary window length, possibly based on psycho acoustics and ear-brain integration time for low frequency sounds. Louis Fielder from Dolby approached me and said that he had done similar work over the last few years on about 18 different cinemas in the USA, and offered to send me his paper. I accepted and found that he had prepared and presented similar results to a SMPTE Meeting in 2012. He had also done and included measurements on the surround sound arrays, where as I was presenting results only from the centre screen channel. I think it would be quite informative if the Fielder paper (presently under SMPTE copyright) was made available to members of this C'tee - action Mark Yonge? SMPTE Meeting Presentation Frequency Response Versus Time-of-Arrival for Typical Cinemas Louis D. Fielder Dolby Laboratories, Inc, 100 Potrero Ave., San Francisco, CA 94103 <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">ldf at dolby.com</A> Written for presentation at the 2012 SMPTE Annual Technical Conference Abstract. Cinema equalization is typically based on the use of 1/3-octave, minimum-phase filtering to adjust the spatial average of the steady-state magnitude response from multiple microphones to the X-curve. This paper explores one aspect of this process, namely whether the use of steady-state response is appropriate. The relationship between early-arrival and steady-state spectral characteristics for typical cinemas was examined. The comparison between early-arrival and steady-state sounds was done via spectral analyses of impulse responses measured at multiple microphone locations within the audience seating area. The cinemas surveyed varied in size between 30-1500 seats and the time-gating intervals varied from 4 ms to that equivalent to steady state. When the survey was done, front loudspeaker measurements above 500 Hz showed little spectral tilt upward toward “brightness” for early-arrival, compared to steady-state sounds, and a modest upward tilt for surround loudspeaker arrays in the largest cinemas. Larger response differences occurred below 500 Hz. Anyway, that's my two pennies worth on a Monday morning. I hope those of you in the UK aren't affected too much by the storm front. best wishes David ________________________________________ From: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A> [<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] On Behalf Of Thomas Lagö [<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">thomaslago at msn.com</A>] Sent: Monday, 28 October 2013 6:50 AM To: Working group on Measurement and equalization of sound systems in rooms Subject: Re: [SC-04-08] Using pink MLS instead of conventional pink nose Dear Peter, Peter, Thanks for your prompt response. Your questions and remarks are tricky and clever. I will try to handle part of it right now. An MLS with a sync signal will NOT behave like a random source since it is a deterministic signal. Without a sync, an MLS behaves "random" and then many of your comments are valid. WITH a sync signal, the length must be longer than the impulse response of interested and together with the bandwidth needed, this sets the clock frequency and hence the length as well. A filtering can easily become "inherent" in the sequence since both the LMS and the filtering follows an FIR filter structure. I have proven this in my designs. For a synchronised signal and a linear system, this becomes less important but crest factor and "out of band" signals will change by the filtering. The basic MLS signal has a "sinc" shape in frequency domain. For LTI systems, the output response is NOT related to the input signal, given that we cover bandwidth and dynamic range properly. For a non-synchronised signal, we enter a completely different domain where we are trying to "emulate" a random signal. Then, length and filtering has a completely different meaning. We need to define how "linear" we are. Do we assume that distortion is reasonably small or not? If not, a random signal will give an LMS estimate and THEN all statistical parameters WILL impact the results since the input signal impacts the result for a non-linear systems but does not for a linear system. Did I manage to explain the difference in signal generator approaches in regards to linear and non-linear systems? Do we assume a synchronised or non-synchronized MLS? For speakers, I always use a synchronized MLS! I might compare with a "random" but my MLS signal is my reference! Best regards, Thomas Lagö On Oct 27, 2013, at 8:52 PM, "Peter Mapp" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> wrote: ><i> Will do when back in uk. Two of the software versions include ability to pink shape the signal. I have B&K filter for other expt or ( it might be interesting to also use your filter but as you already have & my time at the moment is a little limited, perhaps you could do that - at least in the first instance. </I>><i> </I>><i> Perhaps we should explain to Thomas that we are not intending to use the IR potential of MLS, but merely to use as a consistent & repeatable signal signal instead of pseudorandom pink noise. </I>><i> </I>><i> Rgs </I>><i> </I>><i> Peter </I>><i> </I>><i> Sent from my iPhone </I>><i> </I>><i> On 27 Oct 2013, at 19:30, "John Woodgate" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A>> wrote: </I>><i> </I>>><i> In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">2498EF26-E564-487B-A768-0C110D82A366 at petermapp.com</A>>, dated Sun, 27 Oct 2013, Peter Mapp <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>> writes: </I>>><i> </I>>>><i> I have 3 software versions of an MLS signal. Can verif... Expand This file was truncated for preview. Please download to view the full file. 000136.html 3 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>John Woodgate</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CtC1W6pFNTZbSFwe%2B%40jmwa.demon.co.uk%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">jmw at jmwa.demon.co.uk </A><BR> <I>Sun Oct 27 16:33:49 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000135.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#136">[ date ]</a> <a href="thread.html#136">[ thread ]</a> <a href="subject.html#136">[ subject ]</a> <a href="author.html#136">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">DC98EF6CF2F08F40AA5AA23B3509EDA973C6E21235 at KRIX-DC.Krix.local</A>>, dated Mon, 28 Oct 2013, david murphy <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dmurphy at krix.com.au</A>> writes: ><i> Ben Kok was mentioning a duration of about 1 second, saying that if </I>><i>the stimulus and measurement times were matched that was a good thing. </I> A 1 second sequence needs to be repeated until the sound field in the space has definitely stabilized. I fear that for technicians, who often make the actual on-site measurements, that will not sound like noise, because of the glitch at recurrence, and thus create a credibility gap. There is also a question of how long people take to make a measurement: I think it's not as short as others think. A sequence length of some low test of seconds seems to me more realistic. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk If dictionaries were correct, we would only need one, because they would all give the same information. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000135.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#136">[ date ]</a> <a href="thread.html#136">[ thread ]</a> <a href="subject.html#136">[ subject ]</a> <a href="author.html#136">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000137.html 3 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>John Woodgate</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CTiWZCJGDVZbSFwal%40jmwa.demon.co.uk%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">jmw at jmwa.demon.co.uk </A><BR> <I>Sun Oct 27 16:35:47 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000134.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000138.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#137">[ date ]</a> <a href="thread.html#137">[ thread ]</a> <a href="subject.html#137">[ subject ]</a> <a href="author.html#137">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">F36D8618-9ACA-4BDB-8035-299B17D43EB7 at meyersound.com</A>>, dated Sun, 27 Oct 2013, Pete Soper <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A>> writes: ><i>In the situations it is assumed that the system is LTI for all intents </I>><i>and purposes (despite the fact that there are no such guarantees with </I>><i>too many sound systems). </I> For the avoidance of doubt, what is LTI? -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk If dictionaries were correct, we would only need one, because they would all give the same information. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000134.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000138.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#137">[ date ]</a> <a href="thread.html#137">[ thread ]</a> <a href="subject.html#137">[ subject ]</a> <a href="author.html#137">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000138.html 4 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>Pete Soper</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CEA3E0F66-171C-4587-A1F2-517A736566B4%40meyersound.com%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">psoper at meyersound.com </A><BR> <I>Sun Oct 27 16:38:03 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000137.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000139.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#138">[ date ]</a> <a href="thread.html#138">[ thread ]</a> <a href="subject.html#138">[ subject ]</a> <a href="author.html#138">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>"Linear Time Invariant" Sent from my iPhone ><i> On Oct 27, 2013, at 3:36 PM, "John Woodgate" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A>> wrote: </I>><i> </I>><i> In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">F36D8618-9ACA-4BDB-8035-299B17D43EB7 at meyersound.com</A>>, dated Sun, 27 Oct 2013, Pete Soper <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A>> writes: </I>><i> </I>>><i> In the situations it is assumed that the system is LTI for all intents and purposes (despite the fact that there are no such guarantees with too many sound systems). </I>><i> </I>><i> For the avoidance of doubt, what is LTI? </I>><i> -- </I>><i> OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk </I>><i> If dictionaries were correct, we would only need one, because they would all </I>><i> give the same information. </I>><i> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </I>><i> _______________________________________________ </I>><i> SC-04-08 mailing list </I>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I> NOTICE: This email may contain confidential information. Please see <A HREF="http://www.meyersound.com/confidential/">http://www.meyersound.com/confidential/</A> for our complete policy. </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000137.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000139.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#138">[ date ]</a> <a href="thread.html#138">[ thread ]</a> <a href="subject.html#138">[ subject ]</a> <a href="author.html#138">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000139.html 6 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Using pink MLS instead of conventional pink nose </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Using pink MLS instead of conventional pink nose</H1> <B>Thomas Lagö</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Using%20pink%20MLS%20instead%20of%20conventional%20pink%20nose&In-Reply-To=%3CBLU0-SMTP209E62C1258A37181CFF2FCC080%40phx.gbl%3E" TITLE="[SC-04-08] Using pink MLS instead of conventional pink nose">thomaslago at msn.com </A><BR> <I>Sun Oct 27 23:56:03 MDT 2013</I> <P><UL> <LI>Previous message: <A HREF="000138.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000140.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#139">[ date ]</a> <a href="thread.html#139">[ thread ]</a> <a href="subject.html#139">[ subject ]</a> <a href="author.html#139">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>LTI systems mean that they must be linear but also time invariant. This is especially difficult for the low frequency part in rooms. When I developed my RT60 system (1980) using a synchronised MLS signal, Per Bruel could not believe how stable the calculation was at e.g. 50 Hz. The time variability is often neglected but MUST be considered! It is LTI systems in "system theory". I will write some more later but the two signal generator groups exist: 1. Synchronised MLS like MLSSA and 2. A "pink noise generator" for any device that per definition will be non-synchronised. The latter WILL lose all its "MLS unique properties". Both can be made pink or white or "any shape" in frequency domain. Since it sounds like we must develop a "pink noise generator" that can be used by any system, category "1" cannot be considered. Is that a correct understanding? -Thomas On Oct 27, 2013, at 11:38 PM, Pete Soper <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A>> wrote: ><i> "Linear Time Invariant" </I>><i> </I>><i> Sent from my iPhone </I>><i> </I>>><i> On Oct 27, 2013, at 3:36 PM, "John Woodgate" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A>> wrote: </I>>><i> </I>>><i> In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">F36D8618-9ACA-4BDB-8035-299B17D43EB7 at meyersound.com</A>>, dated Sun, 27 Oct 2013, Pete Soper <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A>> writes: </I>>><i> </I>>>><i> In the situations it is assumed that the system is LTI for all intents and purposes (despite the fact that there are no such guarantees with too many sound systems). </I>>><i> </I>>><i> For the avoidance of doubt, what is LTI? </I>>><i> -- </I>>><i> OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk </I>>><i> If dictionaries were correct, we would only need one, because they would all </I>>><i> give the same information. </I>>><i> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </I>>><i> _______________________________________________ </I>>><i> SC-04-08 mailing list </I>>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I>><i> </I>><i> NOTICE: This email may contain confidential information. Please see <A HREF="http://www.meyersound.com/confidential/">http://www.meyersound.com/confidential/</A> for our complete policy. </I>><i> _______________________________________________ </I>><i> SC-04-08 mailing list </I>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> </I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </I>><i> </I> </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000138.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI>Next message: <A HREF="000140.html">[SC-04-08] Using pink MLS instead of conventional pink nose </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#139">[ date ]</a> <a href="thread.html#139">[ thread ]</a> <a href="subject.html#139">[ subject ]</a> <a href="author.html#139">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 0 Comments Public All Members My Connections Only Me PublicAll MembersMy ConnectionsOnly Me Public All Members My Connections Only Me
