more about plate reverbs

June 27, 2009 – 12:17 am

UPDATED:

A few people have asked how this mixer operates and sounds so here’s a wee video:

As you can see there’s a scratchy pot or two to clean and I still need to make some knobs, but so far so good.

Since I posted here about my fancy new plate reverb I’ve made a few adjustments and tweaks.

I’ve chopped the frame down closer to the size of the plate (about 600mm x 1800mm) and stuck a couple more piezos on it, but more significantly I’ve just about finished building a fancy new mixer for it. And when I say “fancy” I really mean “it’s the first mixer I’ve built and it works!”

The piezos seem to give the best results nearer to the edges of the plate (don’t know why) so I’ve got one centred at each end and one centred at each side like cross, and the inputs on the mixer are arranged to correspond to the placement of the piezos like so:

  • left long
  • left short
  • right short
  • right long

The switch on each channel is for determining stereo/mono. The two left channels can be switched LEFT or MONO and the two right channels RIGHT or MONO (e.g. in the picture above the channels are assigned to left, mono, mono, right). This simple arrangement allows for a surprisingly wide range of possibilities.

The mixer itself is insanely simple. It’s completely passive (no amplification) so it needs no power source. The circuit consists entirely of:

  • the 4 input jacks,
  • the 4 faders,
  • the 4 switches,
  • 2 sets of 4 resistors in parallel,
  • and the 2 output jacks. In that order.

I used 4.7 k ohm resistors which seems pretty low according to what I’ve read and heard, but frankly I struggle with the theory of a lot of this stuff so I just tried a bunch of different resistors of different values until I found some which seemed to make everything work ok. The tin it’s all mounted in is mostly empty, so I should be able to fit plenty of other stuff (like preamps) inside without too much trouble if I ever want to.

Do let me know in the comments if you have any ideas or questions. I’ll post some audio clips here soon, probably after the weekend.

For now though, I’d just like to find some more screws and some fader knobs to finish it off. I’m sure there were some around here somewhere…

by felix | posted in electronics, new toys, tips, videos | tagged , , , | comments (3)

just a couple of things

June 23, 2009 – 4:20 pm

Firstly, a few of my friends have started websites and blogs lately and I thought some of you might be interested in some of them. I’ve included links to their feeds so if you don’t have time now, just subscribe to the feeds and check them out later.

Secondly, vote for Lani. Details below.

Adventure in Soundland

Sean makes all sorts of stuff involving (but not limited to) electronics, musical devices and instruments, art, and engineering. He’s started documenting some of it here:

site: http://artyone.blogtown.co.nz/
feed: http://artyone.blogtown.co.nz/feed/

Travelling Tales

AJ is a well known storyteller who has started posting recordings of her stories on her site, kids of all ages can find them here:

site: http://travellingtales.co.nz/
feed: http://travellingtales.co.nz/?feed=rss2

The Idiot Winds

Vincent has begun blogging about “music, film, arts, literature, politics and a fine scotch.” And well worth reading it is:

site: http://theidiotwinds.blogspot.com/
feed: http://theidiotwinds.blogspot.com/feeds/posts/default?alt=rss


Vote for Lani

Finally, Lani needs your votes this week at sellaband.com which is kind of an online competition and fund-raising site for musicians. It only takes a minute and costs nothing to sign up and cast a vote. Lani will buy lollies for anyone who votes for her. Probably.

Righto.

by felix | posted in housekeeping | tagged , , , , , , | comments (2)

how to make a plate reverb

May 20, 2009 – 12:58 am
plate reverb enlarge

Today it stopped raining for long enough for me to do something I’ve been wanting to do for a while - build a stereo plate reverb unit. It took a couple of hours, was made mostly from stuff I found at the tip, cost about $10 and it sounds awesome. If you want to make one of these you can do so with some very basic tools, parts and skills.

The horizontal wires are unrelated. More pics below.

if you’re unfamiliar with how a plate reverb works:

It’s a matter of sending an audio signal to some type of transducer (in this case a speaker) which vibrates a piece of sheet metal (the plate). The vibrations travel though the plate as waves - like ripples from a pebble dropped in a pond - from the speaker at the centre to the edges where they’re picked up by another transducer (in this case 2 piezo buzzers). These convert the wave - it’s shape now altered by the plate - back into an electrical signal and return it as reverb to be blended with the original sound.

Yeah, you can simulate this digitally but analogue plate reverbs have their own special qualities, and if you make your own you’ll be able to create totally unique reverb sounds which are all yours.

As far as I know these type of reverbs were first widely used in the 60s and were considered to be a vast improvement on the earlier “spring” reverbs, the boingy sounding ones that you mostly find these days in Fender-type guitar amps, the ones that make those great clanging noises when you kick them. Don’t kick your amp.

Plate reverbs on the other hand create the rich, dense type of reverb we hear on records by The Beach Boys, The Beatles, Phil Spector, anything from Motown etc etc.

my one sounds like this:

Ok Lani isn’t going to be happy about this, but unfortunately for her this clip is just perfect for demonstrating reverb.

Here’s the dry voice:

and with the magnificent plate reverb:

Here’s a dry guitar track:

and with glorious stereo plate reverb:

the parts i’ve used are

  • An old steel bed frame (could just as easily be built from wood)
  • The side of a filing cabinet for the plate
  • Some small springs from another old bed
  • A speaker
  • Piezo transducers (1 for mono, 2 for stereo)
  • Some light steel wire
  • Some speaker wire
  • Some shielded audio cable
  • Some glue

tools

I used a drill and a pair of pliers. In a pinch you could do it without the drill. Or the pliers.

Oh yeah, you’ll probably need some sort of amp to drive the signal to the speaker. I’m just using my bass head at the moment but I’ll sort out a dedicated amp sometime. Probably.

plate reverb enlarge

The shack I live in is pretty tight so for now the unit is hanging up on the porch. The plate is attached to the frame by springs at either end. I haven’t tried adjusting the tension on the plate or the placement of the springs yet, this is just as it happened to go together.

plate reverb enlarge

The speaker is an old New Zealand made Plessey, suspended on wires (to keep the weight down) and positioned at roughly the centre of the plate.

plate reverb enlarge

As you can see, the front of the speaker cone is about 10mm - 15mm from the surface of the plate. This is just where it happened to land but it seems to work pretty well.

plate reverb enlarge

The piezo transducers are glued to the plate at each end - one for the left channel and one for the right. It sounds great in mono too but if you have a stereo return or a couple of spare channels you might as well give yourself the option.

what now?

  • I’ll definitely experiment with the tension of the plate, I think that could have quite a dramatic effect on the colour of the reverb. At the moment it’s quite dark which is nice for some things.
  • I might play around with the speaker placement, although I’m pretty happy with how it’s working the plate.
  • The piezos only cost a few dollars each so I might try some more in various places around the plate. I think the distance from the centre should relate to the length of the reverb but I’m not sure about that. With more piezos perhaps I could run several different sounding signals to a small mixer and play with them a bit before sending them to the desk.
  • Oh, and I want to build a box for it to live in or find somewhere quiet to hang it. It’s fairly sensitive to wind and dogs.

Any other ideas? Have any advice or questions about building these things? Let me know in the comments.

UPDATE:

I’ve now built a mixer for mixing four reverb returns. Read about it here.

by felix | posted in new toys, tips | tagged , , , , , , | comments (12)

dark night of the soul

May 18, 2009 – 3:11 am

Dj Danger Mouse (one half of Gnarls Barkley, Gorillaz producer, and creator of the legendary Beatles/Jay z mashup “The Grey Album”) is dropping a new record, a collaboration with Sparklehorse and filmmaker David Lynch.

However due to ongoing legal disputes they can’t actually release the album without being sued by EMI, so instead they’re releasing a 100 page book of David Lynch photographs inspired by the music and a blank CDr, leaving it up to the customer to find the music themselves on the net.

The whole album can be heard at npr and it’s pretty, pretty good. Guests include Black Francis, the Flaming Lips, and Iggy Pop.

by felix | posted in music | tagged , , , , | comments (0)

robot monkey orchestra

April 30, 2009 – 3:00 pm

This Friday Auckland sees a rare appearance of the Robot Monkey Orchestra, which is the latest vehicle of head headless chicken Chris Matthews at Cassette Number Nine in Vulcan Lane, 9pm, $10.

Also playing: Charlie Ash, Bang! Bang! Eche!, DJ A.D.A.M.

by felix | posted in music, tips | tagged , , , , | comments (0)

bfm historical society

April 28, 2009 – 10:12 pm

Ok so I’m a bit late to this but every Saturday over at bFM, Dubhead has been running a very interesting documentary series on the history of the station.

Called The bFM Historical Society it’s a series of interviews with people who’ve worked in and around the b over the years, starting in the mid 80s which is about when I started tuning in.

It’s already up to episode 9 but you can easily catch up by downloading them all or listening to them online here.

by felix | posted in radio, tips | tagged , , , , | comments (0)

remix: white collar dub

April 22, 2009 – 8:52 pm

nuff said really.

download mp3

by felix | posted in free stuff, music | tagged , , , | comments (0)

white collar criminal 09

April 16, 2009 – 2:30 pm

I usually get this done a bit earlier in the year but meh - here’s the 2009 version.

Actually here’s the first 2009 version - expect remixes.

p.s. earlier versions here.

by felix | posted in free stuff, music | tagged , , , , , | comments (0)

saul williams - the government

January 21, 2009 – 11:56 am

So I haven’t posted anything over the holidays but I’ve been getting a few projects wrapped up which I’ll post about soon.

Until I do, here’s something that Saul Williams released today. It’s a cool new track, a free download to celebrate President Obama’s inauguration and it’s called The Government.

download mp3

I’m linking directly to the file because his site can get a bit janky to navigate but if you prefer it’s www.saulwilliams.com

The release also states

“The full composition as well as the isolated ‘stems’ are available for download below. Send us your remixes and we’ll post them for listening on saulwilliams.com..or just enjoy the composition!”

but I haven’t found the stems on his site yet. Maybe they’re on itunes? If you find them let me know, I’d love to remix this.

by felix | posted in free stuff, music | tagged , , , , | comments (0)

how to pass the time at family gatherings

December 25, 2008 – 3:58 pm

First, sneak off and find a computer. Which we’ve just done, yeah? I have.

Now just drink until it passes. Here’s a couple of ideas to keep you occupied:

1. Play Auditorium. Speakers on.

2. Watch some hilarious clips of “live” electronic performers faking their shows at deadact.com. Do they think we’re stupid? (Hope that doesn’t ruin your tribal psy-trance raving at the festivals. Or do I?)

3. Listen to some Ricky Gervais podcasts.

Righto.

by felix | posted in housekeeping, radio, tips | tagged | comments (0)