Some 30HZ fun with the AS-1000!

[Doc Mark]

Morning, Friends,

Just time for a short note, but I wanted to share a little experiment that I enjoyed yesterday. With all my wonderings about adding a subwoofer to our L300 system, and to which JBL sub will work best, I've often wondered, exactly, what sort of bass am I enjoying from the CD's to which I've been listening. So, yesterday, in preparation to sweeping our L300's with our Soundcraftsmen AS-1000 Scan-alyser RTA, I dug it out and hooked it up to our system!!

Now, before any testing can be done, I have a few other more pressing matters on my plate, both work related and home repair needs (for Christmas). But, I have very much enjoying "seeing" what sorts of bass I have been enjoying! In this short post, I'll just say that the Boz Scaggs "Dig" CD has some very nice synth bass on a few of the tracks, which reaches SOLIDLY down to 30HZ, or even lower!! Unfortunately, the AS-1000 only reads down to 30HZ, so I have no idea what's happening below that frequency. I am looking forward to seeing just how well the L300's are reproducing what is being fed to them, in the 30HZ region!! More, later..... Take care, and God Bless!

Every Good Wish,
Doc

[jcrobso]

The low A on a piano is 27Hz. 4 string bass low E 42Hz, 5 string bass goes to about 32.
Organ can go down to 16Hz. The thump of a kick drum is very low but hard to determine the exact Hz. John

[grumpy]

The thump of a kick drum is very low but hard to determine the exact Hz.

In fact, it's impossible ... other than a primary resonance (which tends to last longer than
the transient portion). An impulse-like function has a wide-band response. The narrower
the pulse (or at least the steeper the waveform edge), the wider the bandwidth.

It can be surprising how high (in frequency) EQ adjustments can be made to alter
or improve the sound of a kick drum.

That all said, there's lots 'o energy down low as well.

[Doc Mark]

Morning, Gents,

You make some good points, and well taken. I remember, way back in the "old days", being in a fairly nice stereo store in San Diego. The owner was showing off a special set of speakers, who's name actually escapes me at this moment, and was using the "Firebird Suite", if I recall correctly, to do so. In any case, at some point in the music, a 30" bass drum is whacked, and the energy from that drum just about blew me out of the store!!! I was really impressed by the speaker's ability to reproduce that very low energy, and also the upper harmonics that gave it it's "tone"!! I surely wish I could remember the company that made those speakers, but seems to recall that they were custom jobbies, made by someone that the owner knew. In any case, that specific speaker was the only set in his store that could actually reproduce that 30" bass drum with the same stunning impact!! Made an impression on me, that's for sure! Take care, and God Bless!

Every Good Wish,
Doc

[johnaec]

The thump of a kick drum is very low but hard to determine the exact Hz.

In fact, it's impossible ... other than a primary resonance (which tends to last longer than
the transient portion). An impulse-like function has a wide-band response. The narrower
the pulse (or at least the steeper the waveform edge), the wider the bandwidth.

It can be surprising how high (in frequency) EQ adjustments can be made to alter
or improve the sound of a kick drum.

That all said, there's lots 'o energy down low as well.

Using an RTA, plus lots of live sound experimentation, especially when I can get the drummer to experiment with me, I've found that kick drum can be adjusted based on a primary fundamental.

Much monitoring of an RTA on recorded music shows obvious kick drum fundamentals, usually somewhere between 30hz and 60hz, totally depending on the tune. These fundamentals are very easy to see on the RTA.

While seeing RTA kick drum fundamentals on live drums is even easier, I'm often frustrated by drummers that tune their kick drum too "tight, which to me is 60hz or above. I've found that if I can get the drummer to lower the kick fundamental to 40 hz, that's where I have the best luck, assuming the bass blayer is playing a 4-string with a low E around 41 hz. Unfortunately, some drummers feel the drum head is too loose down there and won't do it.

That said, when I've had to deal with Kick around 60 hz, very narrow band parametric can still be used to bring this into balance. Also, as mentioned, adding some high harmonic EQ, (above 800hz), just to the point where you can hear it, really clarifies the sound of kick drum, since you get a sense of when the beater actually hits the head. Without this, clarity is often lost on the kick.

Anyway, that's what works for me...

John

[grumpy]

Nice/useful post, John. Possible analogies in tuning a room too. Thanks

[oldsoundz]

Very cool. Thanks for all of the great reads. Awesome info.

[Titanium Dome]

The AS-1000 and the more sophisticated AE-2000 are still incredibly useful tools today. Certainly more expensive digital gear is available today, but these analog units are a part of my everyday set up and tweaking regimen, and they still amaze me.

The manuals do a good job on the basics, but there's a lot beneath the surface with this 15+ year old equipment, too.

[JBL 4645]

Doc

30Hz you might be off by a few Hz it might be 35Hz or 40Hz or even 28Hz The only way to determine what the frequency response is, is with (Spectrumlab) it’s a free download just look for download at the near top of the page it’s a hyperlink, that will take you down the page to downloads.

It’s rather easy to use once you’ve had a few hands on hours with it.

http://freenet-homepage.de/dl4yhf/spectra1.html

Here are some links that show other recommended settings by members that use it, you’ll have to joint the AVS site to read the file as it won’t allow you in otherwise.

http://www.avsforum.com/avs-vb/showpost.php?p=13937451&postcount=1562
http://www.avsforum.com/avs-vb/showpost.php?p=13937460&postcount=1563
http://www.avsforum.com/avs-vb/showpost.php?p=13937473&postcount=1564

If you like to EQ the sub bass with Behrenger BFQ2496 visit the (Home Theatre Shack) you’ll have to register to download REW (Room EQ Wizard) for free. Also you’ll need to buy a Behringer BFQ2496 LOL and that isn’t free.
http://www.hometheatershack.com/forums/rew-forum/