DIY reverb without springs

cswd · Joined: Dec 17, 2005 Posts: 10 Location: London, UK

Anyone know of a schematic / idea of how to build a reverb using solid state tech (no springs!). I've seen two feasable ideas:

- analogue BBD - but I know nothing about these (I'm a digital / VSLI guy professionally!). Any more info - or has someone made one?

- DSP - but that is just cheating and has latency problems (was looking at dsPIC / TI DSP). Last resort!

Cheers!

bugbrand · Posted: Tue Dec 20, 2005 12:18 pm Post subject:

Springs ARE lovely sounding though.....

Well, reckon you should start looking at the MN3*** load of chips.. I don't know particular chip numbers, but think the MN3007 is used for flangers perhaps and I found this Solid State Reverb Article over at the experimentalistsanonymous.com archives and it uses the MN3011

Now, the problem is that many of these chips are quite hard to find (don;t know of anywhere reasonably priced in the UK (do let me know if you come across any...)) and, therefore, a bit pricey - a good place to check for them is Small Bear Electronics in the US (they mainly focus on pedal orientated parts) --- MN3011 is $15.95

Hey, also have a search for the old Maplin / Realistic Reverb machines - I've got a half-rack one which is pretty bad but could be modded or canabalised.. This definately had MN3*** chips in as did their little reverb mixing desk machine (..these are often only £20 or so on ebay or much less if you come across one at a car boot sale..)

deknow · Posted: Tue Dec 20, 2005 12:24 pm Post subject:

nothing solid state, but i have put speakers and mic's insided pianos and rooms.

deknow

Uncle Krunkus · Posted: Tue Dec 20, 2005 2:10 pm Post subject:

I built my stereo flanger using two copies of a Morely Saphire Flanger. It uses the MN3207 (which is a smaller version) I'd really like to build a copy of the old DM2 which uses the MN3005 (a 4096 stage BBD) but it's really hard to get these chips now. Small Bear has them for about US$30 each. But for the analogue delay/reverb I'd really like to build, I'd need 4 of them. I've got a few schematics and data sheets on this sort of stuff if you want a copy. Maybe we could even trade parts/ideas etc.

ian-s · Posted: Tue Dec 20, 2005 2:55 pm Post subject: Re: DIY reverb without springs

elektro80 · Posted: Tue Dec 20, 2005 3:30 pm Post subject:

Why not build a modern plate reverb device? Retrotech is still in fashion.

elektro80 · Posted: Tue Dec 20, 2005 3:37 pm Post subject:

The EMT is cute.

http://www.nrgrecording.de/html/schematics.html

jksuperstar · Posted: Tue Dec 20, 2005 3:46 pm Post subject:

True, analog reverbs aren't easy to come by. And where to go next depends on what you're after--recreating the sound of some older box, or recreating the reverb of a room? Or just some thickening effect? Although you could use a BBD (or similar time delay) to make a simple model for a plate reverb. But that might be easier to make physically, or some combination of the two (small plate with small Solid State delays for feedback back into the plate?)

Most reverbs these days are done in DSPs, and don't insert much latency, at least it's usually less than the time it takes for sound to travel from a speaker to your ears (hence g2ian's comment about free pre-delay).

I'm an ASIC guy myself, so we might be thinking alike somewhere along the lines. Do you do FPGAs? If you have a little development board, you can get some SPDIF I/O from opencores.org, and then grab lots of info from analog devices here (great resource! .asm for the SHARC dsps, but has detailed .pdfs for each algorithm)
http://www.analog.com/processors/processors/sharc/technicallibrary/codeexamples/21065l_audiodemos.html

jksuperstar · Posted: Tue Dec 20, 2005 3:48 pm Post subject:

looks like Stein beat me to the plate reverb idea... must be a good idea then!

elektro80 · Posted: Tue Dec 20, 2005 3:57 pm Post subject:

Well.. I love plate reverb. The cool thing about plate reverbs is that you can make them as silly and crazy you want to.

elektro80 · Posted: Tue Dec 20, 2005 3:58 pm Post subject:

cswd · Joined: Dec 17, 2005 Posts: 10 Location: London, UK

jksuperstar · Posted: Tue Dec 20, 2005 10:40 pm Post subject:

cswd · Joined: Dec 17, 2005 Posts: 10 Location: London, UK

cswd · Joined: Dec 17, 2005 Posts: 10 Location: London, UK

Just realised my daughter has a slinky. It's almost too tempting (I'm sure she'd kill me though).

Uncle Krunkus · Posted: Wed Dec 21, 2005 5:17 am Post subject:

I've got a mini-slinky, (about 3cm diameter) I know these can be used to make a reverb, but I'm not sure how.

deknow · Posted: Wed Dec 21, 2005 6:49 am Post subject:

http://www.electronicpeasant.com/projects/springs/springs.html

cswd · Joined: Dec 17, 2005 Posts: 10 Location: London, UK

bugbrand · Posted: Wed Dec 21, 2005 9:24 am Post subject:

If you've got a slinky hanging around then put one end over your ear and drop the other end onto the ground - you'll get space-phaser-stun noises. Lovely. You can use a contact mic on one end to faithfully capture this sound. Which makes me think that piezo contact mics may be an ideal form of transducer at each end of a slinky for making spring reverb (gnarly) (&, by the way, I make lovely contact mics for not very much (though you can make them cheaper yourself of course.!.))

Here's an mp3 of a contact mic'd slinky looping in my old dirty sampler (modified answering machine chip)::::
http://bugbrand.co.uk/audio/oneoff/samplerslinky.mp3

Kassen · Posted: Wed Dec 21, 2005 12:22 pm Post subject:

There's another one inbetween the two ways of cheating (Real rooms are cheating and dsp is too). The oil can reverb. Basically the idea is a box with a mike and a speaker in it, except that they filled it with oil. Probably not such a good idea for mobile rigs but at least it's guaranteed to be more exotic then the reverbs the other kids have.

Less dangerous is the "tube reverb". What you do is you take a tube (or more likely a thick hose), put speakers at irregular intervals in the side and a mike in the end. With some math that might work with a little feedback. The advantage of tubes is that they don't leak (like homebuild oil reverbs probably will do (during your vacation, no doubt)) and that you can fold them which conceivably will make them fit in the back of a large modular synth or rack or whatever. I never tried building either but these used to be used by studios if a real reverb room was lacking.

Tubes can be tuned, b.t.w.

deknow · Posted: Wed Dec 21, 2005 2:10 pm Post subject:

...i thought the oil can reverbs used a liquid with a suspended magnetic particles, "flowing" from record to playback heads.

deknow

Kassen · Posted: Wed Dec 21, 2005 2:19 pm Post subject:

Realy? wouldn't that be sorta strange?

OOps; http://www.geofex.com/Article_Folders/oil_can_delays.htm

A quick google prooves you sorta right. Now why and how did that strange bit of disinfo get in my head?

Clack · Posted: Mon Jan 02, 2006 2:27 pm Post subject:

theres this tooo

http://www.tonepad.com/project.asp?id=51

it requires a part from small bear electronics too

Wild Zebra · Posted: Tue Jan 03, 2006 8:32 am Post subject:

I've made the rebote 2 haven't tackled the 2.5 It sounds pretty good. I'm sure you can get some reverb sounds from it. It has some noisy clock issues at longer delays, but it kinda adds to its charm. Its pretty straight forward. And tonepad kicks arse. They have lots of great stompbox projects.

v-un-v · Posted: Tue Jan 03, 2006 2:37 pm Post subject: