MXR 10 band EQ problem UPDATE- It's working

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elvis
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Re: MXR 10 band EQ problem

Post by elvis » Wed Feb 10, 2010 1:03 pm

A string cannot sustain on its own frequencies that are below the fundamental, however, they may be created by manually moving the string, such as with picking. It is usually assumed that picking creates fast transients, as the string is snapped by the pick, but very low frequencies are created by the pick moving the string before it is released. These show up in the "chugging" created by slow rhythmic movement, and are enhanced by palm muting, as high frequency tones are reduced.

The Human ear is more sensitive to tones in the 1kHz-4kHz range, so very low frequencies must be boosted heavily in order to hear them. They are also processed as touch, especially very low frequencies. The music equipment itself (amps and speakers) also tends to reduce harmonic content below 50-100Hz.

Whether or not low frequencies are construed as music or noise by the brain is debatable, but there is no question that they can be produced and perceived. I consider them to be percussive (in effect, noise), as they are NOT related to the fundamental at all since they are produced artificially. The musician is, however, capable of moving the strings at a rate that IS related to the fundamental, or at least to some tone in the music, so may produce related tones by modulating the picking rate.

Wow - that sounds like a boring science paper.
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Re: MXR 10 band EQ problem

Post by Heritage Softail » Wed Feb 10, 2010 1:35 pm

All of that great information aside, did you get your MXR unit working right? I don't think they would dedicate two sliders to a frequency an amp would not normally reproduce for an ear that could not hear it. Just marketing and common sense. Please don't provide any additional arguments. I am still all in a fluster over finding out Al Gore was lying and global warming has dumped 50 inches of snow on my aunts house.

I want to get one of those 10 band GEQ stomp boxes as well. Need to have another tone shaping tool in the box. Have you used a parametric EQ? I see many of those along with the graphic EQ in many racks.
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Re: MXR 10 band EQ problem

Post by boogietone » Wed Feb 10, 2010 8:26 pm

I haven't had a chance to mess with it yet. Hopefully sometime this week.
I had a parametric EQ a while back but sold it. It was a Rane PE15 I think.
I don't really want a rack so I got rid of it. The 10 band will suit me fine.
Even if those two sliders aren't working it has really helped my VHT.
Thanks for all the input everyone.
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Re: MXR 10 band EQ problem

Post by ytse_jam » Thu Feb 11, 2010 3:19 am

Couldn't it be that the audible effect of the two lowest sliders (talking about a standard tuned guitar) is caused more by the tails of the filters influencing higher frequencies rather than that issue about undertones? In every way, I believe those two sliders shouldn't have a great impact on the guitar tone. Depending on the whole equipment, one could hear their effect more and another one could not feel it at all.

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Re: MXR 10 band EQ problem

Post by t0aj15 » Thu Feb 11, 2010 9:40 am

I will repeat what I said in my first post before all this WAY off topic techno-babble started, the MXR M-108 10 band GEQ that I have in my possession DOES FOR A FACT have very useable controls below the 82.41 hz open E string. Both the 31.25 hz & the 62.5 hz controls are very useful and produce sound (not noise) that is easily perceived by anyone other then perhaps the hearing impaired. Before arguing this point I suggest you try one for yourself. I wouldn't have bought it if it came with two non-functioning controls on it.

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Re: MXR 10 band EQ problem

Post by Turumbar82 » Thu Feb 11, 2010 10:03 am

You have to be careful with boosting frequencies any speaker can't handle. A typical guitar speaker doesn't handle much lower than 70Hz. So if you are boosting 31.25Hz and 62.5Hz you are just jeopardizing your speakers. We all know you don't plug a bass into a guitar amp because it will mess up the amp. Why? Because the speakers can't handle the frequencies the bass puts out. So if you are boosting bass frequencies into a guitar speaker that it can't handle you aren't doing anything good for your sound or for the speaker.
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Re: MXR 10 band EQ problem

Post by RectoStudioGuy » Thu Feb 11, 2010 12:10 pm

If you're using V30's here's your usable range...from Celestion BTW, so not likely to be refuted.

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Re: MXR 10 band EQ problem

Post by elvis » Thu Feb 11, 2010 12:35 pm

Oh, now you've done it! Tell people they can't refute something, and they will line up to do it.

:mrgreen:

The frequency range spec is not a useable range, it is the range in which there is not excessive attenuation of the signal. Any speaker will produce 20Hz, it will just not do it efficiently. You can always boost low frequencies and burn more power in the amp to get something out at frequencies outside the specified frequency.

Of course the danger is that when a speaker is not efficient, the power lost comes out as heat. If you push the heck out of a speaker at 20Hz, a lot of that power you put in comes out of the voice coil as heat. With enough heat, you can damage it. BUT you would have to push it well beyond its rated power to do it. So a bit of boost at low frequency is probably harmless. Most of us run speakers at a fraction of their rated continuous power (music signals tend to have high peak power but relatively low continuous power).
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Re: MXR 10 band EQ problem

Post by RectoStudioGuy » Thu Feb 11, 2010 3:00 pm

Not to mention, which many seem to forget, that a guitar is essentially a mid-range instrument and thereby best used as such.
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Re: MXR 10 band EQ problem

Post by elvis » Thu Feb 11, 2010 6:08 pm

What about my drop-A 7-string (OK, I go with standard tuning, but some people drop A). I still want to hear it when I dive-bomb. I think I can get to 1 Hz that way.

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Re: MXR 10 band EQ problem

Post by RectoStudioGuy » Thu Feb 11, 2010 7:02 pm

I keep one of my 6er's tuned in C and even that only goes down to 65Hz or so.
Main Rig:
#6 of 14 '91 PRS
LD Ch. Studio Pre (MkII C+)
RH Ch. Recto Pre
G-Major
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Pair of 2X12's (Swamp Thangs on Closed Back V30's on Ported)
...some other stuff of course


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Re: MXR 10 band EQ problem

Post by soundchaser59 » Thu Feb 18, 2010 8:54 am

Why dont you just plug a bass into the 10 band, turn the two lowest sliders all the way up, slap the low E string and see if you blow your speaker?

There are all kinds of things that will prevent you from hearing those freqs, especially since 31 and 62 are below the fundamental of the low E on a guitar. If you turn the lowest slider all the way up you should hear at least a little bit of difference with heavy chord digging and palm mutes. Do anything on your guitar that sounds like a kick drum, and make sure you have the low EQ on your amp turned up. As long as you are not using 6 or 8 inch speakers, you should hear something change.

You probably cannot work on this eq pedal yourself, I was told (by a person who mods MXR's for pay) that the MXR EQ uses some type of monolithic construction inside, similar to the monolithic crap all the old Alesis toy mixers were using. If that's true, I would think either all the sliders would work or all the sliders would fail, not just one or two of them.

So somebody believes he can get his guitar to play 1hz? I have a 98 Ford Ranger for sale, mint condition.....best car ever made, great bargain. Call me.
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Re: MXR 10 band EQ problem

Post by boogietone » Sat Feb 20, 2010 8:23 pm

So I took it apart and didn't see anything wrong at all. I put it back on the pedal board
and I cranked the bass on my VHT's clean channel and while hitting low E and adjusting
those two sliders up and down I could hear the two freqs in question working. So, I guess
nothing was wrong after all. I guess being that it's a EL34 based amp and maybe the freq
response of the speakers (PE50's made for VHT by Eminence) made it difficult to hear.
I'll probably hear it better through my DC-5 being a 6L6 amp that has more low end. Though
that amp doesn't need it. Anyways, thanks for all the input!
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Re: MXR 10 band EQ problem UPDATE- It's working

Post by davidstvz » Wed Apr 14, 2021 8:24 am

I know this is an ancient thread, but I found it in a search for info and figure others might find it and benefit from what I'm about to write.

There has been discussion about whether or not the 31.25 and 62.5 hz sliders of the MXR should affect low guitar tone because the 62.5 hz slider is lower than a guitar's lowest fundamental frequency of 82 hz.

Those low sliders absolutely *should* affect low guitar tone. The lowest 3 bands on the MXR are 32.25, 62.5 and 125. 80 hz is just above 62.5 and would obviously be affected by that slider since the EQ action tapers from the center point and 80 hz is between two sliders

However, more than that, each slider in a graphic EQ affects frequencies above and below the neighboring sliders (just not as strongly). If the bandwidth affected by each slider was super tight so that it had virtually no effect by the time it reached the next slider, the resulting EQ would probably sound strange (if you raised a series all by +6 you would get big dips between the sliders). So long story short, if you raise the 62.5 hz slider it will raise frequencies at 80 hz and even well beyond 125 hz. It very much has an effect on guitar tone. If you want more low end, use the lowest sliders like a shelf. Raise all of them.

Don't worry about your guitar amp speaker. Most guitar speaker cabs/amps should have bass limiting components that cut out anything low enough to put the speaker easily at risk due to bass overload. PA's which are designed as full spectrum and need to be able to output very low bass may need protection... that's usually when you would use the mixing board to roll off or cut the low frequency content. When singers play with their mic stands for example, the movement can cause a lot of annoying low pitched sounds which you can mostly cut out with a judicious low cut.

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