The filters in Drawmer DS201

[Dayo]

I really badly need a sweepable outboard high pass filter. Drawmer gates run pretty cheap on Ebay, and I recall they had a sweepable filter on there.

Impresions anyone?

I like to think I run a pretty high spec mic chain: Lawson L47, Fearn VT1, EL8 and Neve Portico EQ.

If I insert a Drawmer gate in that path does anyone think I'll be degrading the integrity of my chain? It's really only the filter I need it for and I probably won't use the gate.

Yes I know there's a filter on the EL8 but it's set a tad high for my liking. And I can't get what I need from the Portico Low Shelf.

Any ideas?

(I know it's not strictly high end, but hopefully my my chain is)

[davedarling]

the filters are great. The signal quality is great...they're a great piece of gear.

if you buy one used, make sure that it doesn't crackle when you turn the knobs.
Other than that they're built like a tank.
I still use one for a rumble filter into PT.
as a bonus, they do a gated trigger that sounds different than anything I've been able to do in the box.

good luck dd

[Michael Loomis]

Just so you know, I believe the filters on this unit are on the side-chain, and are there to be used for "frequency-conscious" gating. The filters do not affect the actual audio directly. Then again, I suppose you could use the side-chain listen feature to pass the filtered audio, but I do not know if the sonics of the side-chain are up to par with that of the primary audio circuits.

Michael

[Dayo]

Originally Posted by Michael Loomis

Just so you know, I believe the filters on this unit are on the side-chain, and are there to be used for "frequency-conscious" gating. The filters do not affect the actual audio directly. Then again, I suppose you could use the side-chain listen feature to pass the filtered audio, but I do not know if the sonics of the side-chain are up to par with that of the primary audio circuits.

Michael

Aha! Very interesting - food for thought.....

[Bassmankr]

Look into the Aphex expander/gate units.

[Pereds]

ds201 is good enough.

[Karloff70]

Get the drawmer! In fact, you're making me want one back just for the filters. They're really nice and musical in action. Always loved using them as eq's on mixes! Can't see how you wouldn't like them.

And as Mr Darling points out, they are THE tool for dance music style choppage!

[davedarling]

Originally Posted by Michael Loomis

Just so you know, I believe the filters on this unit are on the side-chain, and are there to be used for "frequency-conscious" gating. The filters do not affect the actual audio directly. Then again, I suppose you could use the side-chain listen feature to pass the filtered audio, but I do not know if the sonics of the side-chain are up to par with that of the primary audio circuits.

Michael

ahh grasshopper -the "key Listen" switch is what you seek.
As I said, I use the unit as a rumble filter (on audio) from time to time, and to MY highly tuned professional record making ears it sounds good.

dd

[thethrillfactor]

Originally Posted by davedarling

ahh grasshopper -the "key Listen" switch is what you seek.
As I said, I use the unit as a rumble filter (on audio) from time to time, and to MY highly tuned professional record making ears it sounds good.

dd

Also you can use it for the side chain EQ for your main mixbuss compressor instead of dedicating a unit for this purpose.

[davedarling]

Originally Posted by thethrillfactor

Also you can use it for the side chain EQ for your main mixbuss compressor instead of dedicating a unit for this purpose.

CORRECT !!

At one point, you have to ask yourself - "can I really make a record WITHOUT a Drawmer 201 ?"

I think not.

dd

[Empire Prod]

DS201's are good to have around. You can do lots of cool stuff with them. They are cool for ducking as well.

[soundsundergroun]

I have the 404.

So wait a minute, you mean I can use just the filters when I switch to key listen?

I never even thought to do this.

[Jim Williams]

Used to use 201's back in the 80's. Now I use Aphex 612's, much, much better.
Lower noise, lower THD, wider bandwidth, smoother filters, more control. It's also an expander so it can uncompress tracks too. I don't use the gating function much, no noise here to gate. But the expander function is great as is the side chain filters which I use all the time.

Jim Williams
Audio Upgrades

[Dayo]

Jim - do they have a key listen feature like the Drawmers?

Originally Posted by Jim Williams

Used to use 201's back in the 80's. Now I use Aphex 612's, much, much better.
Lower noise, lower THD, wider bandwidth, smoother filters, more control. It's also an expander so it can uncompress tracks too. I don't use the gating function much, no noise here to gate. But the expander function is great as is the side chain filters which I use all the time.

Jim Williams
Audio Upgrades

[Bassmankr]

There is the older Aphex 612 (2 channel rack) and the same thing, the Aphex 9611 (1 channel module); and the newer Aphex 622 (2 channel rack) and the same thing, the Aphex 9621 (1 channel module). The main difference between them are the newer 622/9621 has a parametric key filter with one knob for frequency and the other for bandwidth (Q). The older 612/9611 has knobs for low cut and high cut filters. They all have features that most gates don't such as Hold and Range. The Hold knob sets it up so that once the gate is open, it won't close until the Hold time has passed (prevents machine gun opening/closing) so you can set your threshold tighter. It has an ultra fast attack time .1ms variable to a couple of seconds. The newer 622/9621 has a small headphone jack so you can listen to the key signal and has some logic assistance. Gate/Expander/Ducker, here is a link to Aphex's site and their 622. APHEX Systems 622 Logic Assisted Expander Gate I've never compared the Aphex's to the Drawmer's like Jim (I've got (2) 9621's and (6) 9611's) so if you already have a Drawmer, I'd say just use the tool you have. If looking for a unit then check out the Aphex's.

[Jim Williams]

Originally Posted by Dayo

Jim - do they have a key listen feature like the Drawmers?

Yes, plus external key and duck switches. The filters are 12 db/octave butterworth slopes. The high pass does 30 hz to 3.5k, the low pass 150 hz to 15k hz. You can even tune them at 300/3k for that 70's english telephone sound. I use the filters more than the expander. Sometimes I use them to pre filter reverb sends as keeping the high frequencies out is better than reverberating them and trying to filter the highs out in the reverb filter. It's great for keeping the cymbal wash out of drum overheads as an example. Got mine used at the Audio Effects auction years ago for $125. This one is tweaked and direct coupled, no caps.
DC to 200k, -1db with the filters out.

Jim Williams
Audio Upgrades

[Ciozzi]

Originally Posted by Jim Williams

Yes, plus external key and duck switches. The filters are 12 db/octave butterworth slopes. The high pass does 30 hz to 3.5k, the low pass 150 hz to 15k hz. You can even tune them at 300/3k for that 70's english telephone sound. I use the filters more than the expander. Sometimes I use them to pre filter reverb sends as keeping the high frequencies out is better than reverberating them and trying to filter the highs out in the reverb filter. It's great for keeping the cymbal wash out of drum overheads as an example. Got mine used at the Audio Effects auction years ago for $125. This one is tweaked and direct coupled, no caps.
DC to 200k, -1db with the filters out.

Jim Williams
Audio Upgrades

Very informative. BTW do you know what order are the filters in the DS201 ? 12 dB/oct ?

[Dayo]

Thanks very much for the extra input Jim; a couple of supplementary questions for you please:

For v/o; if I'm right I could use one side as a high pass filter, then route that key output to the input of the other side for a bit of expansion or gating? Mono source, of course.

I've seen reference to Butterworth slopes before, but I'm not sure how that translates to what we do. Does it mean a steep slope? A gentle one? Or is it more to do with the way it handles the corner of the frequency?

I believe the later model Aphex has a tunable Q. In practice does that mean I would be able to get more control over the slope of the filter? IMHO, for voiceover it ought to be quite steep, but without phasiness or too much thinning of the frequencies just above your target. Hope that makes sense!

Lastly. is the mod worth doing? I got my techie to mod my Neve Portico EQ just recently and was thrilled at the way it focused the sound and made it somewhat drier. I'll resist the phrase "night and day" - it'll only stir things up!

Originally Posted by Jim Williams

Yes, plus external key and duck switches. The filters are 12 db/octave butterworth slopes. The high pass does 30 hz to 3.5k, the low pass 150 hz to 15k hz. You can even tune them at 300/3k for that 70's english telephone sound. I use the filters more than the expander. Sometimes I use them to pre filter reverb sends as keeping the high frequencies out is better than reverberating them and trying to filter the highs out in the reverb filter. It's great for keeping the cymbal wash out of drum overheads as an example. Got mine used at the Audio Effects auction years ago for $125. This one is tweaked and direct coupled, no caps.
DC to 200k, -1db with the filters out.

Jim Williams
Audio Upgrades

[Jim Williams]

Independent channels can be routed any way you want. Butterworth slopes are maximally flat response, some phase anomolies. They are the most common curves found and are used in many mid level converters as a reconstruction filter. They tune well and have smooth looking curves.

Bessel or linear phase filters are prefered but rairly found in a sweepable configuration. They have relaxed curves so the slopes are less steep at the turnover points. Extra poles are needed to get the tightness of a butterworth slope. Those are found in high end converter DAC's as reconstruction filters and they have superior transient response without ringing.

Drawmer filters are also mutiple feedback 2 pole filters like Aphex. The ones with Q controls increase resonance at the turnover point, pretty useless for general filtering uses unless you want to use the low pass as a guitar pickup emulation as an example. That was the basis for the Alembic guitar circuits.

Jim Williams
Audio Upgrades

[Dayo]

Thanks for that Jim

I'll look out for the older Aphex gate then.

[littlesicily]

Is there a way to mod the 612 so the low cut and high cut can be engaged independently?
Reason is sometimes I want to lop off some lows from a vocal but not affect the highs. Even when the high cut is wide open, I still hear some high end loss.