Asking G: Microphone techniques in recording

[gregorio]

But the NYT article is going over more advanced modeling of one location: full reconstruction of each area in the cathedral based on materials and and dimensions.

No, that’s pretty standard procedure, they’ve been doing that for many years. Modern concert halls are designed that way, computer modelling of materials and surfaces with calculations for different parts of the auditorium to optimise the listening experience for all audience members. I remember spending nearly an hour testing the acoustics in a new venue designed this way (about 20 years ago) and was amazed that the acoustics seemed to be the same wherever you went in the auditorium. Never experienced that before, even the world famous acoustic venues have at least some areas of the auditorium that are significantly different.

I just find it amazing that they also have an acoustics team that can help dictate how the reconstruction should go.

Nope, that’s also standard procedure and has been for several decades. Russell Johnson was the pioneer in this field and a world leader almost until his death. I was very fortunate to spend a couple of days with him when I was working with an artist giving the opening performances in a major new concert venue (nearly 30 years ago).

I'm still skeptical that they would be able to model those venues at the same level as what's being done with Notre Dame now

Yes they can and have been able to do so for many years and to an extent likely better than what’s being done with Notre Dame, because you can actually go to those venues, record/measure the acoustics and then “convolve” an output modelled to that specific venue/location.

What seems unusual in this case (although I can’t read the article) is that they’re trying to reconstruct a specific acoustic without knowing what it was originally. EG. Using computer modelling to predict what the acoustics would have been and then modelling methods/materials to recreate that/those acoustics. Rather than being able to go there and just record the impulse response/s. In other words, the whole thing would be effectively algorithmic as opposed to partially “convolution”, the impulse response would be calculated/modelled rather than recorded.

especially if your DSP won't let you set specific areas at The Berlin Philharmonic hall.

There wouldn’t be much point in that for consumers. If you could choose any sitting location in a world class concert hall, why would you choose a poor position (thereby rendering it a non-world class acoustic)? However, although you don’t find it in consumer products, you do commonly find it in professional products (and have for many years). It’s use is usually restricted to Film/TV though, where different locations within an acoustic space can be important.

G

 

[Davesrose]

Sure, I can understand that there's up to date computer modeling for designing new music venues. But is it really common place that an acoustic team is included in restoring buildings, and they use thorough computer modeling to simulate acoustics for every location in the building?

Checking out the NYT article with headphones is worth it if you have access. They have demos of how medieval chants sound in different areas (and they say there was up to a 20% loss in resonant sound after the fire). So it's a limited example of a consumer interface letting you pick different locations (the intent to show difference in sound based on size/ height of ceiling). The article doesn't get too deep, though. One of the main things they've done is clean a massive amount of dust (with everyone wearing hazmat suits because of the contamination). Might be interesting to see if there's a noticible difference in sound with clean stone faces.

 

[bigshot]

The DSPs on my AVR have control panels with adjustments, but the names of the adjustments are very technical. I don't really know what they do. I'm guessing though that you could fine tune it to be back of the house or front of the house at least. Maybe more. I just use the defaults though.

 

[gregorio]

But is it really common place that an acoustic team is included in restoring buildings, and they use thorough computer modeling to simulate acoustics for every location in the building?

I don’t know if it’s common in general building restoration, it is common when restoring concert venues. And yes, they are very thorough.

Checking out the NYT article with headphones is worth it if you have access.

I don’t have access. This plugin will give you an idea of what is used professionally.

The DSPs on my AVR have control panels with adjustments, but the names of the adjustments are very technical. I don't really know what they do. I'm guessing though that you could fine tune it to be back of the house or front of the house at least. Maybe more. I just use the defaults though.

No, not quite the same thing, that’s an algorithmic reverb and those adjustments are the reverb parameters. Changing those parameters changes the fundamental properties of the generic acoustic, for example the room size, shape, initial reflection delay, etc.

G

 

[Ryokan]

@gregorio where would you place the mics for the trumpeters in the gallery?

 

[gregorio]

Good question and as previously in this thread, the two questions of “what do we want to end-up with and how do we want to get there?” are vital. In this case, the off-stage trumpets provide both some difficulties and some options, so a conversation with the conductor would have been required.

For example, how off-stage/distant does the conductor want the trumpets to sound? And, there is a trade-off here, because the more distant/reverberant they sound the less well they will balance with the on-stage trumpets and the rest of the orch during the tutti section (distance is perceived as quieter even if it isn’t!). I have to say, that the choice in this case of what they ended-up with was quite different from what I would have done/advised. Verdi’s Dies Irae is one of the most dramatic movements in the whole of romantic period classical music and I would have wanted to represent that fact more. We see the off-stage trumpets on the far left and right of the stage but in the mix we hear them pretty much in the centre, more or less the same position as the orch trumpets just slightly more distant. Obviously there must have been dedicated mics for the off-stage trumpets because if just the main array had been used, the OS trumpet would have sounded hard left and right, although the whole orchestra is mixed very narrowly, not far off mono, the choir is a little wider and the reverb wider still.

Given the time/budget, I would have used two directional mics flown quite close (10ft or so) to each of the two OS trumpet groups, to provide some isolation and options for mixing. EG. I could pan them quite hard left and right and use EQ, compression and an artificial reverb with a custom IR to create the distance. This would have mitigated the balance/distance issue above. The problem of recording the OS trumpets with actually distant mics (to capture the distance) would be where to put those mics so they’re not closer to the orch trumpets or indeed the rest of orchestra during the tutti section. Flying the OS trumpet mics very high would probably result in more bass drum, timps and tuba than OS trumpets because trumpets are fairly directional and they need to face the conductor. I would really need to examine the hall and/or already know it well to come-up with viable solutions. I initially thought it was Suntory Hall in Tokyo, which I know a bit but it’s some other hall I’m not familiar with.

Incidentally, my criticism of the mix may not be the fault of the engineers, for example mono compatibility may have been a high priority if it was broadcast live. It’s certainly not a bad recording/mixing job, it’s entirely competent but could have been significantly better (more electrifying) in my opinion.

G

 

[bigshot]

The Beatles recorded stuff in a stairwell at Abbey Road studios. I know in Wagner's Ring, the hunting horn is usually placed backstage near the dressing rooms. I guess the secret to distance cues lies more in the envelope around the sound than the sound itself. It's easier now with digital reverbs.

 

[gregorio]

The Beatles recorded stuff in a stairwell at Abbey Road studios.

Yes, that was very common back in the day and the stairwell, corridor or toilet at a few studios became famous. However:

I know in Wagner's Ring, the hunting horn is usually placed backstage near the dressing rooms.

Yes but in the case above, we’re dealing with a live performance where the OS trumpets can be seen and they have to also see the conductor. I presume it was intended by Verdi to be performed in a large church/cathedral with the trumpets in an alcove or balcony somewhere.

G

 

[gregorio]

I thought this vid might give a bit more of a balanced perspective. It’s a recently released short documentary about one of the top recording studios in the world (AIR Lyndhurst) and probably the best IME. There tends to be quite a varied but generally inaccurate view of what sound/music engineers are and what they do. Some audiophiles seem to think we’re just deaf technicians, out to destroy the music and who don’t know much about the technical side either. Others don’t have such an automatically negative view but still don’t seem to appreciate what the role really is. This video demonstrates the more holistic nature of the role and also hopefully explains why some of my answers have been deliberately somewhat vague.


G