Re: Ask an Acoustic Engineer (me)
Re: Ask an Acoustic Engineer (me)
That is interesting, because double that distance and you are right about 1800hz to 2200hz, or your problem area. So sound that travels up and bounces back down off of the windshield could be canceling itself out. If I am thinking correctly about that. My mind is tired this week (first week teaching all digital has me teaching like its worse than my first year (more work). At least my first year things were already created by others and I could use them and just get through the year, not a lot of stuff created for an all digital science learning experience).
Re: Ask an Acoustic Engineer (me)
Quote:
Originally Posted by
Justin Zazzi
Fun question!
I enjoy seeing the advancements in materials used in speakers. The thin-ply carbon in TeXtreme is really impressive stuff. I've done some experiments and validated it when I was at Eminence and then my good friend Matt built it into the compression driver n314x. I left the company before the project was finished but I heard it has a really well-behaved sound like we were predicting during development. I see a couple other drivers on the market with this material and I'm excited to see something with performance similar to the "best" materials like beryllium but at a fraction of the cost.
http://www.textreme.com/markets/audio-2/
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Another material I hope becomes mass-produceable is carbon nano-tube technology but in the meantime a Canadian company is making graphene membranes which are also carbon-based. I bought into the kickstarter for the ORA headphones and I'm really impressed with them. It could be that I've never had a premium headphone before, but I'm really amazed how they sound. They are like nothing else I've ever heard.
I'm also excited to see advancements in the digital signal processing realm. The first generation Apple and Google smart speakers solved a problem where the bass output of the speaker would change depending on where you placed it in a room. If you put it on a table in the middle of a room then the bass output would be less compared to if you put it in the corner of a room or up against a wall. These smart speakers had microphones that would detect it and adjust the bass output accordingly so it would always sound good no matter where you put it. They would also adjust how to distribute the higher frequency information to the array of tweeters too so when against a wall it would play a left and right channels to one side of the room and the other, or if in the middle of a room it would be more omnidirectional to fill the whole room and you'd never be on the "wrong" side of the speaker. I love this approach to make the technology "just work" so the consumer can put the speaker wherever the speaker fits into their lifestyle and it will adapt, but the neat trick was it adapted automatically and you didn't have to push a button to go into "corner mode" or "party mode" or whatever like some products have done before.
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Speaking of technology advancements, I'm also excited to see my friend Niick join JL Audio a while back. He has some wicked ideas and although I'm out of the loop on the cool stuff he's working on now because I'm at Rockford and we are competitors, I can't wait to see what he's been doing all this time. I'm sure something amazing is on the horizon and I'm looking forward to it. However, I'm doing my best to create amazing stuff at Rockford too so we might have a couple products that I'm excited about when they get released too : )
The other thing that really sticks out to me was watching the Falcon Heavy test launch where Elon's Tesla Roadster was launched into space and the twin booster rockets landed side-by-freaking-side on the launch pad. I remember watching that in real time and I had goosebumps and was jumping up and down yelling at the screen. I guess that was my moon-landing moment where I got to see something magical happen for the first time.
https://www.youtube.com/watch?v=wbSwFU6tY1c
There is also Pozyx which created a local 3d positioning system that is accurrate to within 4 inches. This is kinda like GPS but it's local and uses radio waves and can work indoors or through walls. I find it neat because I've always wondered if you could attach location data to a microphone measurement, then what applications would that open up? If you could map the sound field inside a vehicle or inside a room, would that help you with positioning or aiming speakers or selecting and placing sound treatments?
https://www.pozyx.io/
I love technology so I could go all day with this so I'll finish with a neat little thing we can all afford. The Uni Kuru Toga is a mechanical pencil that automatically rotates the led as you write so you always have the sharp side facing the paper. I had one for a long time but lost it at the office and I just ordered another. The roulette version has a metal body that feels just right in the hand with the perfect weight and I freaking love it. And they are super affordable too. Best $10 I've ever spent on a pencil.
https://www.jetpens.com/blog/kuru-to...e-guide/pt/706
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Just watched that youtube of Falcon heavy dual landing. Pure Goosebumps
Re: Ask an Acoustic Engineer (me)
Quote:
Originally Posted by
jscoyne2
just watched that youtube of falcon heavy dual landing. Pure goosebumps
i know right!?
Re: Ask an Acoustic Engineer (me)
Quote:
Originally Posted by
Justin Zazzi
i know right!?
INCREDIBLE!!! WOW! Had goosebumps too!
Re: Ask an Acoustic Engineer (me)
Quote:
Originally Posted by
cueball981
INCREDIBLE!!! WOW! Had goosebumps too!
Speaking of goosebumps, try this:
Extended Cut - The Incredible Sounds of the Falcon Heavy Launch - (BINAURAL AUDIO IMMERSION)
(skip to 10:00 for the launch)
https://www.youtube.com/watch?v=x7uQ8OWiheM
Re: Ask an Acoustic Engineer (me)
That's got some super low earth moving bass.
Re: Ask an Acoustic Engineer (me)
Quote:
Originally Posted by
Grinder
Very cool Grinder, thank you for sharing.
I love that guy's channel too.
4 Attachment(s)
Re: Ask an Acoustic Engineer (me)
Quote:
Originally Posted by
Justin Zazzi
I think you're talking about reverberation time which is usually measured with "RT60" or "RT30". Room EQ Wizard can calculate this for you. Essentially it means how long does it take for the room to get quiet again after the music stops. This is, like all audio things, frequency-dependent. The goal that Jon was chasing is to have a specific reverberation time for all frequencies to better mimic the behavior of a performance hall or a place where music is performed ... instead of sounding like a car which is relatively dead.
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image borrowed from Jon's website here: https://www.magicbus.biz/measurements.html
so i did a deep dive in your old build threads and opened every link that anyone posted. Seriously i have like 25 links open in chrome right now heh. I stumbled upon this.
http://www.bnoack.com/index.html?htt...tingrooms.html
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Attachment 14082
First off. This starts at 100hz so its missing some critical information for cars with a ton of cabin gain. More importantly though. The shape of the concert hall reverb times is what i'm looking at. To get our cars sounding large and spacious. We should be using that curve as a "house curve" for our entire 20-20khz reverb times in our vehicles. However, we are never going to get 1.8 seconds of reverb in our cars but then i saw the 2nd picture and realized that concert hall times are higher because the overall volume of the space is MUCH MUCH larger than ours. So we should be able to just take that overall shape and just bring it down like you would in REW dropping levels, like this VVVV
Attachment 14083
Thoughts?
Re: Ask an Acoustic Engineer (me)
Seems like you have the right ideas. I'm not sure what it would sound like to have the same reverberation time "shape" but shifted down like you show. Jon Whitledge put a spectacular amount of effort into making his sprinter van have a good reverberation time and his project would be a good one to study. Look for his website and the build log where he talks about the binary amplitude diffusors and the numerous bass traps he built for that purpose. He also has lots of graphs and theory to go with it.
In general though, yes it's hard to have a longer RT with a smaller interior volume. I once thought about making the RT longer artificially with some clever electronics like the "stadium" or "hall" modes on home theater receivers but never got around to it.