High frequency attenuator

[rockambo]

I have two rigs. One the cabinets of both there is a high frequency attenuator. I keep this on -6 db, but I have no idea what this does. I mean the high frequencies go to the horn, but first, I'm a bass guitarists not a flautist. I play a five-string bass and I mostly play low, not high.

The first rig is the Ampeg Portabass 100w with a 210 cabinet, this has the high frequency variable l-pad control which I keep at 75 percent on, but should I just leave it completely engaged? If perceive no difference either way (maybe I'm deaf in the upper register?).

The second rig is a TE AH100 Series 6 100w, Crown CE2000 power amp, a SVT-410HE. and an SVT-15E Classic. I have recently been experimenting with different combinations. To me, the 410 is listless and heavy, but the TE head with the 15 is punchy, dynamic, and sounds great. I have attempted to play with the attenuator to see if I can get more out of the 410, but it just is lifeless and dark. My next experiment will be to daisy chain the TE to 410 (with attenuator full on) and then to the 115 versus the TE to the 115 (with speakon in and out) to the 410 (with the attenuator full on) and see which gets combination gets a better sound.

Honestly, I am thinking of scrapping the 410 in favor of another 115. Any insight is appreciated.

 

[KJung]

Whether you are playing 'low or high' on the neck, every note at every position of the bass has a full range of frequencies. On a good bass with relatively new strings, there are a LOT of treble frequencies in the open B string note.

An attenuator is a simple volume control for the tweeter in a multiway cab. Most crossovers are set in the 2K to 3.5K region, which is right about where a typical bass driver starts to roll-off and not reproduce much sound above that level.

Tha markings 'flat', 0 DB', "6db, whatever, are typically arbitrary. Some cabs with very powerful tweeters with low crossover points (i.e., a lot of sound coming throught the tweeter) can sound very tinny and harsh at the 'flat' or 12 o'clock/0 db level. Other cabs can still sound dark with the attenuator turned all the way clockwise (i.e., 'out of the system, with the tweeter on full).

If you have a rather dark sounding bass (like a P Bass with older flatwounds) it's very possible that you won't notice a different in tone at various attenuator levels, especially if the crossover is set high (so that only the upper treble is coming out of the tweeter). If you have a full range instrument and use stainless steel roundwounds, the tweeter might be a very important tool in getting that treble grind and sizzle that some like out into the room.

So, to directly answer your question, the attenuator is a volume control for the upper treble frequencies. The more it is turned clockwise, the more volume comes out of the tweeter relative to the woofers. Use your ears to set it where it sounds good to you. If you find it sounds best 'off' (fully counter clockwise) then you know that if you buy a new cab, you can buy one without a crossover and tweeter!

K

 

[rockambo]

thanks for the information! This gives me some ideas to work with.

 

[KJung]

thanks for the information! This gives me some ideas to work with.

You can't really hurt anything by experimenting with it. In some crossovers, it's not a good idea to turn the attenuator all the way counterclockwise. So, even if you don't like the sound of the tweeter, it's a good idea (I think) to leave the attenuator just slightly to the clockwise side of 'off'. You won't hear it.

For the vast majority of cabs, I've found a tweeter setting between 9 o'clock and 11 o'clock most pleasant (i.e., resulting in the cab to provide a relatively even response from the deep lows to the sizzly highs.

However, if you like an aggressive, somewhat distorted rock tone, a tweeter can sound VERY nasty, and is best left almost off.

Use your ears and you will figure it out.