simurg3 t1_iy89e3q wrote on November 29, 2022 at 2:21 PM

I don't quite understand the push back against the multiple drivers. Here are my observations:

I have never heard a sound reproduction system that can be even closer to the original sound of the orchestra. During reproduction, the timbre of the instruments, the fidelity of the multiple instruments producing the sounds together are lost. As the source of sounds gets more complex, the worst the divergence gets.
A single driver cannot produce all frequencies at the same magnitude. That's why we have subwoofers. Low frequency sounds from a smaller driver cannot have the same magnitude as the larger driver. Just like a large drum sound louder than small drum for the same frequency.
A driver cannot immediately changes its movement due to inertia. Now there are techniques like planar drivers, electrostatic drivers to reduce the challenge but each solution comes with its compromise. This is also why we have equalizers to compensate on the physical limitations of the driver.

Now going from a single to multiple drivers introduce more noise as we add more processesing. Yet it also adds more flexibility to reproduce sound by using specialized driver for given target frequency.

We also need to understand the source of the sound. For orchestral sound like classic music, jazz music, the challenge is higher as the goal to reproduce original sound. For pop and rock music, sound is already engineered as there is no original sound but multiple soundtracks that are mixed by an engineer for optimal listening pleasure for target configuration. For the latter, two drivers are sufficient if the sound engineer targeted headphone based listening.

In a world with perfect microphone and perfect driver, yes we only need two drivers but they are not. The music is also not always mixed, prepared for two drivers.

therealrydan t1_iy9f5ew wrote on November 29, 2022 at 7:07 PM

> For orchestral sound like classic music, jazz music, the challenge is higher as the goal to reproduce original sound

I think this is incorrect. It's not any more difficult to correctly reproduce a recording of an orchestra than of pop/rock or even entirely DSP-generated sound. The challenge is probably rather in recording the music in the first place.

If you would record an orchestra with a high quality binaural rig, run some 3d-scanning + DSP to correct for the shape of your head and ears, and listen through high quality headphones, you would probably not be able to tell the difference (atleast not if we assume we could achieve a truly blind comparison, that is, you would not see whether it was the orchestra playing or not, and that you wouldn't feel if you had headphones on or not...).

You only have two ears after all, and they just react to sound pressure level changes in a very small volume of air.

simurg3 t1_iyaxlxz wrote on November 30, 2022 at 1:17 AM

I agree that the bigger challenge with reproduction could be at recording. We must still recognize the challenges associated at the speakers to perfectly reproduce the sound.

I don't agree with orchestral music and rock/pop/digital music having the same challenge.

I was actually going to ask what prevents recording companies to produce binaural records. It cannot be technical as production costs for such music cannot be too high. Music consumption is more and more through headphones or Iems, especially for critical audience. Yet there is almost no records coming with binaural recordings. What ama I missing?

therealrydan t1_iyc1sbv wrote on November 30, 2022 at 7:26 AM

Binaural doesn’t translate well to speakers. (And it’s slightly flawed in that it still doesn’t model your specific head/ears so without significant wizzardry it won’t be 100%)

But yes, as more and more music is listened to through headphones, I’m kind of wondering this as well…

There are a lot going on with stuff like Atmos though, and virtual studio simulations for mixing in headphones, so we might see interesting things in the future.

Re repriduction of different kinds of music I think the challenge is exactly the same. The challenge is to reproduce a signal with flat frequency response, correct transient and phase response, with low distorsion. As long as you do that, you reproduce every kind of music well. There may be tradeoffs that ate more important in some kinds of music. Soundstage/positioning perhaps being more important than sub bass in jazz/chamber music but (perhaps) not in EDM for instance. But I still think the challenge is the same. Have a good enough system and everything will sound good on it. Or be correctly reproduced atleast, which may not be what sounds the best, but that’s a whole other can of worms.

That can of worms may also be part of it, because, we might for the most part not actually want the recorded music to sound like the real thing, we want larger than life. Have an anecdote from a former colleague who's worked a lot on recording classical music for radio and TV. He had this story where he worked on an audiophile symphonic recording. They used a small set of really high quality microphones, set up as a blumlein pair as main source + some more microphones to capture and be able to adjust tonal balance, width and room in the final result. Apart from slight corrective EQ, they weren't supposed to process the sound at all, it should be all natural. Compression or artificial reverb were strictly prohibited. They did several different mixes with different mic balances, but the producer weren't satisfied and still thought it sounded unnatural. So, without telling anyone, they sent the mix through a Manley VariMU compressor, just compressing a few dB:s at most. That's the version that got released...

simurg3 t1_iydgqp5 wrote on November 30, 2022 at 4:16 PM

I was hoping that recording companies sell both versions of the same album. One for speakers and one for headphones.

Your anecdote resonates with my understanding. The music we listened is enginereed to sound good and optimal. For pop/rock music, engineering is part of the creative process. As you mentioned that classical music recordings are supposed to adhere to source but they also get edited. Thanks for shari

therealrydan t1_iy985pm wrote on November 29, 2022 at 6:21 PM

It’s a question of amplitude. In theory, a single driver is optimal, since it’s a point source. Creating a driver capable of loudspeaker sound pressure levels, that can reproduce the entire human hearing frequency range with high resolution and low distorsion is tricky (almost impossible). Doing the same at headphone audio levels is much much more doable, probably even easier than overcoming the problems with multiple drivers and extremely short listening distances. With multiple drivers you also have crossovers, with their problems and added distorsions and phase issues.

Also, you have technologies as planar magnetics or electrostatics, that are very difficult to use well at loudspeaker volumes, but extremely viable at headphone levels. (Electrostatic designs are also an example of a seriously high-performing single driver loudspeaker, albeit one that requires BIG speakers if you want full range bass reproduction at somewhat respectable levels.

In the loudspeaker world, some companies are jumping through a substantial amount of hoops just to get speakers to behave like a single point source even though constrained by the need to use multiple drivers, like Genelec TheOnes (three-way coaxial point-source design with substantial audio and DSP trickery...).

Most (all?) high end headphones are single-driver designs. If there would be substantial advantages to instead using multiple drivers I'm sure many high-end headphone designs would, but they don't...