il manque les graphes:
Hey guys,
I feel pretty humble posting clips with all these fantastic players on the forum, but I figure that this was actually a valuable test that some of you would like to see. The point of these are not to show off chops or style, but to be as "scientific" as I can. Please remember that when you laugh at the brain dead riff I played for these clips. But I wanted to play something so simple that I could do it in my sleep, repeat it a million times without needing more than one take ever, and focus on the test methodology itself.
So basically, this test is designed to address the following questions:
• Do attenuators "suck sound?"
• Is it better to use the master volume of your amp to reduce the level?
• Is there a difference between the THD Hot Plate and the WeberVST MASS?
To try and make this test as objective as possible, I decided to use not only my ears, but my eyes. After the clips were recorded, I ran them through Elemental Audio's Firum for its EQ curve Analyse function, so as to get a snapshot of the EQ curve of the file.
These tests were done with my Rivera KH2 amp. It is a very low-end heavy metal amp that really "opens up" once the master volume is past 5. The settings for the KH2 were absolutely identical in all clips except the clip in which the master volume was reduced. Keep in mind that results may vary depending on the amp, but for high gain amps, I think the results should be rather similar.
My Cabinet is an Antone 2x12 with a G12H30 and a V30 inside. The recordings were done using my Royer R-121 Ribbon mic (about 8" from the center of the cab), into my Requisite Audio PAL (tube pre/limiter), into the Metric Halo Mobile I/O (interface connected to G5). This is a pretty prestine recording path. What you hear in the soundfiles is what was going on in the room.
First off is our "control" tone. This is the KH2 with the master volume at about 6.5. This is loud enough to shatter glass and start small fires.
http://www.mertonfolio.com/KH2(...)e.mp3
As you can see from its EQ curve graph:
There is between a 6dB and 9dB bump in frequencies from about 80Hz to 900kHz, and the curve drops below 0dB around 2.5kHz or so.
Next, I lowered the Master Volume to around 3. This is still loud enough to wake the neighbors, but if you don't play for long, the police might not get called.
http://www.mertonfolio.com/KH2(...)n.mp3
You can both see and hear this is a completely different tone. The graph shows clearly that the bass boost almost never reaches 6dB, and that in fact the 3dB to 6dB boost continues all the way until 3kHz, where it finally starts to drop off.
For the rest of the clips, the Master Volume of the KH2 is back at 6.5. First, I had the WeberVST MASS set to about 8 on its dial (not severe attenuation at all) and the Treble Boost switch ON.
http://www.mertonfolio.com/KH2MASS.mp3
As you can see and here, it did a good job of capturing the bass response of the KH2, but the mid-range and treble is pretty compromised:
The peaks and valleys follow a very similar path, but they are just different enough, and the high frequency falloff with the MASS is just steeper enough, that there is an overall dullness to the sound. I saw no point in testing the MASS with the Treble Boost OFF, since even with the treble boost it was lacking treble.
Next up, I tried the Hot Plate at a setting of -8dB with the BRIGHT switch ON:
http://www.mertonfolio.com/KH2(...)t.mp3
This is a totally different sound, somewhere between the non-attenuated clips of the master at 6.5 and 3. A look at its EQ curve confirms this:
The bass boost isn't as large, and the treble doesn't roll off until over 3kHz.
Then I tried the Hot Plate at -8dB with the DEEP switch ON:
http://www.mertonfolio.com/KH2(...)p.mp3
This both sounds and looks incredibly similar to the first clip:
Not exactly, but all the peaks, valleys, and rolloffs are in the same frequencies. Only at the extreme high end is there a far steeper falloff.
Since the Hot Plate with DEEP on did so well at -8dB, I decided to push my luck and try the Hot Plate with the switch at -16dB and the fine knob at about noon (for a reduction of about 30dB-32dB). This is truly "conversation level." You can have friends sit behind you and not loose their hearing, your pets will still love you, and so on.
http://www.mertonfolio.com/KH2(...)D.mp3
Surprisingly close! A quick look at the graph:
Shows that there is some loss at the very low end, and a bump around 3kHz - 3.5kHz, but overall a good match to the original.
Conclusions
I posted all the clips and graphs so that everyone can use the information to come to their own conclusions. But mine are:
• It is definitely preferable to use an attenuator to reduce the room volume and leave the amp cranked than it is to use the master volume to lower the amp's volume.
• Different attenuators definitely have different sounds, and affect the sound differently.
• For the KH2, the Hot Plate with DEEP switch engaged captured the original tone very well, even at crushing levels of attenuation.
Anyway, I did these tests to figure these things out for myself, but I hope this information is useful to others as well. I'm sure your results may very with other amps, and different people may prefer different sounds, even if the sound isn't necessarily the closest one to the original tone.
Orren
