subective "Ice Pick" frequency

[pjd3]

Hi there.

This is a very loose question based on your own personal experience but, have you ever closely determined which frequency or frequency range which you discovered as the "ice pick" frequencies should they be undesirably predominant? It is something I know when I hear it but, never actually scoped in to see what frequency(s) or range of frequencies it constituted. I'm imagining it is around 3-4K or so but, it would be fun to see what your experiences were.
As I get on with finishing up a 2204 with mods project I'm keeping this in sight, as where I like a good dash of upper mid cut, I'm not a fan of severe Ice pick.

Thanks!

PD3

[Reeltarded]

Very subjective and very much depends on situation.

Cutting above it is better than directly targeting it.

You are timid before startup. If your amp is facey you might prefer different era (early) slope and treble.

[sluckey]

I don't consider any particular frequency as being ice pick. Rather, the frequency response of the amp is such that the higher frequencies are much greater than the low and mif frequencies, ie, treble boosted, bass and mids cut. Set to controls for a more balanced response curve and the ice pick usually goes away.

[Stevem]

I think there are many factors that govern this to one degree or another.

In no particular order.

1) voice coil cover material of speaker (s)
2) if amp has global feedback which extends the high frequency responce.
2B) if the Ot is interleaved.
2C) if the amp is being played loud enough to cut back on the feedback voltage.

3) the room the amp is played in will make high frequencies much more dominant if it’s has a lot of hard surfaces around the amp and within 10 ft of the front of the amp.

4) semi open back combo amps will accentuate the 2 to 4K frequencies, especially if not being played loud enough to move the cone and push around a good amount of air.

5) the tone stack used on many amps and especially those that have a dedicated clean channel have a mid cut to them, some so much that the only way to get any amount of mid boost is to cut way back on the bass and the treble.

Some amps that have a mid control apply more of a cut then a boost.

[pjd3]

Very interesting feedback all,

It looks like the "ice pick" syndrome is a bit more involved than gust a band of frequencies. All through the years you hear talk from audio engineers about 2-4K being the "fatigue freq band" and they will look closely at this area to make sure it doesn't get too out of hand. I had to wonder if it was even loosely related to the ice pick syndrome.

Thanks, great stuff.

Phil D

[Roe]

3k is rarely ice pick. around 5k is more likely.

it is best to remove treble late in the circuit, and to remove bass early on, esp with gainy amps

[Reeltarded]

Very interesting feedback all,

It looks like the "ice pick" syndrome is a bit more involved than gust a band of frequencies. All through the years you hear talk from audio engineers about 2-4K being the "fatigue freq band" and they will look closely at this area to make sure it doesn't get too out of hand. I had to wonder if it was even loosely related to the ice pick syndrome.

Thanks, great stuff.

Phil D

The first session with all big condenser mics at Western was Sinatra and the tech notes that day said to add 8k roll-off on every channel. The Thursday session started the BIG VOCAL ERA and jazz for the next 5 years sounds so importantly amazing because of that one change from ribbons to condensers and the 8k roll @-6/oct.

This is a fair analogy for using early era presence values and smaller treble cap to smooth out an 800. 50p over the 82k in the output is a great other thing, but going over 100p on the snubber there will just make the amp thuddy if it isn't a raging gain monster.

[pjd3]

being able to low pass some highs in the later part of a circuit sound like something very nice to have.

I like the idea of a healthy amount of harmonics being generated the way a preamp will, and then just gently rolling them out to taste.

Thanks,

Phil D.

[JD0x0]

3k is rarely ice pick. around 5k is more likely.

it is best to remove treble late in the circuit, and to remove bass early on, esp with gainy amps

I guess that's where the subjectivity comes from. IME, 3k sounds harsher and more forward than 5k-6k even though they are higher frequencies. There's a somewhat scientific reason for this, as well. The 3khz range is also a common range for a baby crying. The human ear is supposed to be most sensitive to frequencies in this range, and these also tend to be the last frequencies to go when a human is losing their hearing.


A good trick for removing treble late in circuit is the VHT 'Texture' style switch. It puts a low pass right at the OT, so it will even cut harsh overtones produced in the output tubes.

[WhopperPlate]

Ice pick frequency :

JBL K120s and e120s

Takman resistors

UL Fender Twins

Marshall Super Lead DIY Clones

Blue LEDs (on my eyes)

Etcetera etcetera

Edit for pjd3:

lets go off the rails then …

precisely 50% of all ODS clones (the other half don’t have any ice pick)

Majority of “boutique” amps turned up past comfortable listening volumes.

“Jcm800 , recently completely serviced , replaced all caps and resistors , brand new JJs, runs perfect! Local pickup only”

“Transparent” boosts

Reissue vintage amps

Hammond miniature die cast pedal enclosures

Ironically , more or less a non existent frequency in modern guitar production , either EQd out at the board , in the preamp /poweramp, at the speaker, or in the computer algorithm .

A frequency heavily diminished by low quality modern vacuum tubes. You don’t know true icepick until you run old glass through old iron with an old tele bridge. More like a pick axe. Modern tubes seem to ping more than they pick .

Obviously I am describing the sensations rather than the literal specific frequency ,though there are certainly intersections

[pjd3]

Oh come on Whopperplate, keep going:
Etcetera etcetera,

You were doing good!

[pjd3]

Just curious,

What do you suspect it is about DIY Marshall Super Lead 100 clone's that are making them Ice-picky?

Best,

Phil D.

[WhopperPlate]

Just curious,

What do you suspect it is about DIY Marshall Super Lead 100 clone's that are making them Ice-picky?

Best,

Phil D.

Metal film resistors
Mercury magnetics
Modern silver mica caps
F&t caps
Mox power resistors
Ceramic tube sockets
“Perfect” lead dress
Overrated power transformer specs

Throw in some hifi components within the signal path that the builder thought would definitely “ make an improvement “ and you are almost guaranteed to have an unforgiving ear grater that you can call boutique .

Someone will play it in isolation with a decent guitar and be blown away long enough to pull out their wallet, before eventually returning to playing their vintage amps , or better yet their cheap 5W modeler amp.

[WhopperPlate]

Oh come on Whopperplate, keep going:
Etcetera etcetera,

You were doing good!

I updated it for you

[JD0x0]

Just curious,

What do you suspect it is about DIY Marshall Super Lead 100 clone's that are making them Ice-picky?

Best,

Phil D.

I think those older Polyester caps like the 'Mustards' and Mallorys have more dielectric losses than modern caps resulting in a smoother sound. During my early years of modding/experimenting, I swapped out all the polyester caps from my 80's PCB Hiwatt and exchanged them for 6PS and 715P caps, and the highs went from a silky 'violin-like' quality to a much harder, more focused high end, which could easily be perceived as more 'ice pick-y.'
I think modern metal film resistors also contribute. Old carbon film resistors will tend to drift up, and that can result in a 'smoother' sound.