Re: [Sursound] Submersed in Subs (and ideas) (Eric Carmichel)
determine the direction of a 40 > Hz sound. > > But because the transition frequency is 700 Hz for conventional Ambisonic > decoders and 400 Hz for domestic decoders (thanks, Martin, for this info), it > seems plausible to make this the electronic crossover point as well. The > woofers, if properly placed, can handle frequencies that have unambiguous > direction as well as the difficult-to-localize low lows. This, then, would be > akin to a two- or three-way speaker system, only better: The woofer would > receive a signal that is position-specific. So now I?m thinking what Fons and > Martin wrote is a plausible solution to my space/channel count/directional > lows concerns. Of course, this will require a speaker with a smooth 40 Hz (or > lower) to 400 Hz response that can deliver a fair amount of distortion-free > energy if the low-frequency sound emanates from an extreme L, R, front, or > back direction. Somewhat more clearly: If one speaker has to do the work of > six working in concert, it can still manage the signal. I > don?t plan on blasting anyone out of the room, but low frequencies > originating from well-defined directions do exist in the stimuli. > > I won?t have to fly the speakers making up the centre (horizontal) array; > only the speakers suspended from the ceiling have to chosen based on their > weight and size. I?m doing this in a modest-sized room, not an auditorium. > Having said all of this, upping my channel count to from 16 to 18 would > require a minimal change, and therefore I could provide three horizontal > arrays of 6 loudspeakers each. The upper and lower rings/arrays will produce > frequencies above 400 Hz only, while the center (horizontal-speaking) array > provides the 400 Hz and below energy. (Kind-of like six really stretched out > two-way speaker columns, only with Ambisonic decoding for the mids and lows). > > Other suggestions that I?ll try include adding a Focusrite (or similar) D-A > to the system and Reaper software. I?m not sure, though, if Reaper works with > MIDI automation, and I use a MIDI-based system of my design to collect data > and automate faders. I?ll find out soon enough. There are certainly a lot of > ideas to consider. If I didn?t already have a great field recorder, I?d > certainly get the MOTU Swiss Army knife... I mean Traveler... in addition to > the MOTU 896HD I have now. I already have more than 16 channels worth of > analog outs, but not all hardware devices at my immediate disposal share the > same software driver. I believe adding a second MOTU and a D-A (Focusrite or > Behringer) is a great option. > > On a wholly different note: Next week I?ll be making an Ambisonic recording > in the Superstition Mountain Range, located in Arizona. In the mornings, > there?s a low-pitched steam whistle that blows from some type of facility > west of the mountain range. There?s quite a delay (at least 5 s) before an > echo is heard from one trailhead, but the large cliff face on the mountain > and the obstacle-free desert terrain makes for interesting illusion: You?d > really believe there?s a second steam whistle up in the mountains. There?s > very little ?spectral? modification of the whistle's sound as the sound > travels across the distance, and both the whistle and resulting echo are loud > enough for a good SNR. Curious as to how a recording of this will sound on my > home rig. I?ll share the wav files as soon as they?re processed. > > As always, many thanks to everyone for your time and insights. > Best, > Eric C. -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130302/2b238c9e/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Looking for a very, very old thread - mics pointing inwards?
Michael Chapman wrote: > 1) Don't think this is it, but better to forward than delete ? Yes, I also found that post, but it isn't quite what I was looking for. Maybe my imagination is just making up things. Thanks Michael. Eero ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Looking for a very, very old thread - mics pointing inwards?
Hi Are you thinking of the arrangement that one of the audiophile record companies use? Near coincident fig 8's plus an omni pointing in. Every Blessing Tony > -Original Message- > From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On > Behalf Of Eero Aro > Sent: 02 March 2013 11:06 > To: sursound@music.vt.edu > Subject: Re: [Sursound] Looking for a very, very old thread - mics pointing > inwards? > > Michael Chapman wrote: > > 1) Don't think this is it, but better to forward than delete ? > > Yes, I also found that post, but it isn't quite what I was looking for. Maybe > my imagination is just making up things. > ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] Ambdec Presets
Hi all, This message is directed to Fons, i have been using your excellent ambdec for a while now with horizontal set ups, mostly using an octagon, to do HOA decoding of spot mic recordings, and also experimenting adding other decoders in to introduce height element via a cube configuration for ambience e.t.c. using soundfield mic. However there are obvious drawbacks with this which are annoying, because one decoder does the horizontal, and another for height there is no possibility for a homogenous rig. You do say in your manual that you could on request generate presets for set ups, (big ask) but could you generate a couple of presets (1st, 2nd order) for my rig please? Thanks, Paul Power -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130302/062c7305/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Looking for a very, very old thread - mics pointing inwards?
Tony wrote: Are you thinking of the arrangement that one of the audiophile record companies use? Near coincident fig 8's plus an omni pointing in. No. I am writing an article about an un-orthodox stereo recording setup, "common acoustical point". Two cardioids with a reasonably long spacing, pointing towards a single source, so that the on axis directions cross. The setup works and has some advantages compared to mono miking and it works well with single instruments and in a reasonably anechoic recording space. But as you see, it isn't a stereo recording setup as such. It's more like a twin mono miking setup. You need to be careful not to create comb filtering. The setup reminded me of a discussion of a similar type surround recording setup. Four or several mics on a circle around the source would capture a LOT more time and phase differences between the channels than a stereo setup. Eero ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Looking for a very, very old thread - mics pointing inwards?
Hi Not come across that one! I often use ORTF stereo set-ups, especially if I don't want the pin point accuracy of Blumhein. I'd be interested if you do turn up a reference. I've used the Faulkner array of spaced figure of eights with some success. I did read that he'd more recently added further mics - I can't remember/find the ref. now - maybe it was in "Resolution" magazine. I thought I'd kept the article, but I can/t find it in my file, and there doesn't seem to be anything on the web. Maybe that's what you're thinking of? Every Blessing Tony > -Original Message- > From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On > Behalf Of Eero Aro > Sent: 02 March 2013 17:17 > To: sursound@music.vt.edu > Subject: Re: [Sursound] Looking for a very, very old thread - mics pointing > inwards? > > Tony wrote: > > Are you thinking of the arrangement that one of the audiophile record > > companies use? Near coincident fig 8's plus an omni pointing in. > > No. I am writing an article about an un-orthodox stereo recording setup, > "common acoustical point". Two cardioids with a reasonably long spacing, > pointing towards a single source, so that the on axis directions cross. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] Ambisonic-specific loudspeaker system
Hi Steve, Thanks for writing and sharing your interests and insights (Sursound Digest Vol 56, Issue 2). It is always interesting to get input from people with different backgrounds, and it sounds as though you have an extensive background in the recording arts and music production. I know what you mean about the “obligatory” NS10; in fact, one appears on the *Products* page of my personal site (cochlearconcepts.com) along with a 4000-series SSL console, and a classic combination of music production gear (e.g. tubed UA and Manly compressors). [The ugly dude in photo is yours truly.] Like many audio enthusiasts, I got into hi-fi as a youngster. I was an avid speaker builder, and authored a couple of articles in The Audio Amateur and Glass Audio magazine. As a person with some loudspeaker design experience, I took note of your comment, “This would also slot nicely into the change of directional hearing mechanisms, while at the same time not having a crossover in the centre of the most important mid range. It would also reduce the interference caused by placing drivers close together.” It’s interesting that many loudspeaker designs (to include highly regarded powered monitors) have a crossover point right smack in the middle of the ear’s most sensitive frequency range. The trade-offs for higher or lower xover frequencies are 1) the larger-diameter mid-woofer becomes directional at higher frequencies (all relative to cone diameter); 2) typical dome tweeters can’t manage the power or long cone excursions needed to reproduce low frequencies; and 3) adding a mid-range driver adds to the complexity of the design as well as physical size of loudspeaker system. I’m not saying anything you don’t already know here. But what could be interesting is designing an Ambisonic-specific loudspeaker system to offset the crossover frequency. I’m personally biased towards at least one single-coned, full-range driver: The Lowther (ok, it has a whizzer cone, but still no crossover network). But these guys are expensive, and the one pair I had were mounted in massive, acoustic-labyrinth enclosures. But on a more realistic notion, there are many good speakers that have smooth on- and off-axis responses from roughly 40 Hz up to 700 Hz. And I’m confident there are more than a few single-coned 4- or 5-inch drivers that can accurately reproduce 700 Hz to well beyond the upper mids. To complete the high-end, a tweeter (or array of tweeters) could be added. An analog (passive or active) crossover at 700 Hz wouldn’t be needed, as the B-format signal could be split into specific bands (high and low) ahead of the decoding. [This, by the way, is where I intended to do offline processing.] Such an arrangement would require two Ambisonic decoders (upper band and lower band decoders with their own, unique speaker sends). Fortunately, this isn’t a big processing load. I’d prefer to do this than split the highs and lows after decoding with a single decoder. If the crossover frequency was chosen to be 700 Hz (or 400 Hz), then a greater number of place-specific speakers could be used for the highs (as you suggested) than for the lows. The mids and highs could easily be grouped together (for economy). The loudspeakers handling 400 Hz and above could be two-way, but with a higher-than-usual crossover frequency (meaning conventional crossover but at, say, 5 kHz). Such a system would have atypical crossover frequencies, but the advantage would be keeping the crossover point out of the ear’s sensitive range as well as the range where phase anomalies (introduced by active or passive filtering) could be most audible. The directional characteristics of the drivers are a function of baffling and cone diameter, so cone diameter and enclosure size would be purposely small for the speakers managing 700 Hz and up. If such a system provided advantages, I suppose it would be ill-suited for any of the popular surround formats. The workaround would be to stack the smaller (one- or two-way) speakers atop the bass/mid-bass speakers and bi-amp them. Time alignment and additional subs optional. Many thanks for taking time to read. Best, Eric C -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130302/e3bf91d3/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
