The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Sourcing a parabolic dish to use with omni mic
Old 7th April 2017
  #1
Here for the gear
 

Thread Starter
Sourcing a parabolic dish to use with omni mic

Hi,

I'm working on a project that involves recording distant nature sounds: birds, insects, frogs, the elements, etc. I have no budget unfortunately for a shotgun mic but have a spare pair of DPA 4060 omni mics and I'd like to experiment using one of these with a parabolic dish. I'm looking for ideas on where to look and I'd like to find out what sort of materials and sizes are best. I'm looking to source a dish locally in Brazil where i live rather than buying online, which gets expensive here due to to import duties and the exchange rate.

My first thoughts on where to source parabolic dishes are lighting shops, both domestic and theatrical. Domestic supplies would most likely be in plastic or in aluminium. Do either of these materials give better results? I imagine aluminium might resonate whereas plastic might have have better damping qualities.

If I source a dish from a lighting shop it will no doubt have a hole in it for the lighting element. Can this simply be covered over with sheet metal or plastic with a smaller hole made to run the mic lead? Any specific considerations here?

What sizes work best?

I've heard of people using woks - there are Japanese supermarkets here - I guess they have woks, I've never looked.

Commercial cooking supplies may have big mixing bowls in plastic or steel but perhaps they wont have a well defined focal point.

Please let me know if you have and ideas or can offer some guidance.

Thanks,
Old 7th April 2017
  #2
Lives for gear
You sound like a DIY kinda guy...a man after my own inclinations !

If you get a cheap 1970/80's style pendant light shade, I'm guessing it will come with a 2-3 cms diam. globe/bulb fitting already attached....you won't need the fitting, but the plastic locking ring(s) may well come in very useful, so don't throw those away !

Having obtained your dish, you can go to a plumbing/water pipe shop which has a variety of various diameter plastic/PVC threaded pipes. You buy the outer diameter to match the hole in the light shade, then glue strips of rubber foam inside the pipe-tube so that it will hold the mic in place. Ideally you might want to slide the mic up and down inside the 'focal point' of the parabola, so that you get maximum output gain from the mic....and then lock it in position with the threaded nylon nuts.

Initially, if it's not raining, you might simply lie the dish on the ground...mounting it on a mic stand can come later...if it works ? Make sure you have a plan B ready if it begins to rain....I doubt the 4060 would like rainwater drops at all !!

I think a wok might have a metallic ring-sound to it, whereas a PVC or acrylic light shade would be more neutral ? You can probably get the light shade from a secondhand furniture shop for $5 or so ? Look for plastic/acrylic versions of those pictured.
Attached Thumbnails
Sourcing a parabolic dish to use with omni mic-lampshade-1.jpg   Sourcing a parabolic dish to use with omni mic-lampshade-2.jpg  
Old 7th April 2017
  #3
Lives for gear
 
Thomas W. Bethe's Avatar
Old 7th April 2017
  #4
Gear Nut
 

Old 7th April 2017
  #5
Here for the gear
 

Thread Starter
Thanks a lot Thomas and Studer58. I think I'll definitely try out the 70s style shade and yes, great idea re. making use of the lock nut and I guess the pvc pipe can serve as a handle. How do you find the sound quality of these parabolic mics compares to shotgun types? Cheers,
Old 7th April 2017
  #6
Lives for gear
 
PatrickFaith's Avatar
 

Try large plastic trash can lids. YouTube "make parabolic", a lot of sound artist have made a bunch of really nice installation pieces but they are too heavy for field work. I use telinga stuff, DIY can work well but things like pans and glass shades are hopelessly phasey (ok if it's more of a sound design feel I guess).
Old 7th April 2017
  #7
Old 7th April 2017
  #8
Lives for gear
 

I still have the Sony dish. A few observations:
1: a small dish like this has a definite "sound", which I ended up doing a lot of EQ to flatten out--very peaky hi mid no matter what mic (I mostly used a Schoeps) or position in the mount.
2: it transmits a lot of both handling noise (from your hand on the grip if you are holding it), from wind blowing over the dish (even if the mic itself is well protected) and very much from rain and snow if that might be a part of your plans. We had to rig up a covering for it made from some location-motel towels to deal with this issue.
3: a small dish like this will hear next to no low end, and not hardly any low-mid either. If ended up being a tool for recording birds, squirrels etc in fairly quiet environments

All in all I wasn't crazy about how this thing performed at the high-gain settings needed for nature recordings. I'd wager you could do at least as well on your own for cheap. If you can, make the dish be MUCH bigger than that of the Sony.
Old 8th April 2017
  #9
Lives for gear
 
Thomas W. Bethe's Avatar
Quote:
Originally Posted by philper View Post
I still have the Sony dish. A few observations:
1: a small dish like this has a definite "sound", which I ended up doing a lot of EQ to flatten out--very peaky hi mid no matter what mic (I mostly used a Schoeps) or position in the mount.
2: it transmits a lot of both handling noise (from your hand on the grip if you are holding it), from wind blowing over the dish (even if the mic itself is well protected) and very much from rain and snow if that might be a part of your plans. We had to rig up a covering for it made from some location-motel towels to deal with this issue.
3: a small dish like this will hear next to no low end, and not hardly any low-mid either. If ended up being a tool for recording birds, squirrels etc in fairly quiet environments

All in all I wasn't crazy about how this thing performed at the high-gain settings needed for nature recordings. I'd wager you could do at least as well on your own for cheap. If you can, make the dish be MUCH bigger than that of the Sony.
A lot depends on the microphone chosen. I tried a lot of different microphones with my dish from an AKG blueline to AT 4051s to a Tascam microphone with built in batteries. They all sounded different. I always used a tripod which eliminates handling noise and a good quality wind screen which got rid of a lot of wind noise. I was just at Sam's Club and the have a big plastic salad bowl for restaurant use that looks like it would be great for a DIY parabolic microphone. It looks similar to this. https://www.amazon.com/koziol-PALSBY...tic+salad+bowl

Best of luck!
Old 13th April 2017
  #10
I teach a class with a section in room acoustics. I've found that walking around a concert hall with one of those Sony parabolic systems along with headphones and a single metronome source sounding on the stage is a fantastic way to experience and investigate room acoustics. As a result, I've been collecting them on eBay and craigslist. We have 2 of the smaller 330 models and one of the larger 400 dishes.

I've not used them to record. If the above poster is correct, you should look for one of the larger PBR-400 models. Unfortunately, they are much harder to find and don't show up very often...

I also wanted to say that these parabolic reflectors are generally used with a directional microphone so that it can point directly at the center of the reflector.
Old 13th April 2017
  #11
Gear Head
 

The point of a parabolic dish is that it is actually a parabola. Other rounded shapes are bound to be phasey because they don't reflect back to the same point. Wouldn't something like a satellite dish work?
Old 14th April 2017
  #12
Lives for gear
Quote:
Originally Posted by Andy Le Vien View Post
The point of a parabolic dish is that it is actually a parabola. Other rounded shapes are bound to be phasey because they don't reflect back to the same point. Wouldn't something like a satellite dish work?
Yes, you need a true parabola.
Most consumer satellite dishes are asymetrical/offset so you don't have to point them directly to the sky. Not exactly what you want for a microphone.



Some of the larger dishes are normal parabolas, but they aren't really portable.
Loading mentioned products ...
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump