AudioPhiles don't want NEUTRAL, Audiophiles Don't like NEUTRAL (Part Two)

Folks, just because a speaker or amp starts to roll off at a certain frequency, doesn't mean there is no response below that point. If a speaker is down a few db at 40hz, there is still plenty of signal there. All it takes is a little boost in that range from an equalizer and it's all there and more. Of course that cuts down the headroom a bit, but that's usually not a problem if you have good gear and aren't running at maximum levels.

In fact, I have a 25 Hz equalizer I run before my subs. I just get about a db or so out of it, but it helps with that bottom octave and the natural roll off of my speakers.

 

Played on a system with excellent low bass response, you hear some, of course but not very much. You THINK you hear a lot on car radios and portable players and home consoles, because you hear the "artificial bass effect".

I don't have a SVT head handy but if I did I'd get a dummy load and run some sweeps into my AP Portable One. How much is cab and how much is head? Dunno.

 

Electro Voice made a 30" woofer, called the 30W. A lot of them ended up in electric church organs. Somehow that product ended up in the Altec/University catalog in the '70s and '80s.

I want to try a 30W in a dipole sub someday.

 

Didn't Van Halen tune down a 1/2 step? That would be Eb then.

 

Ampeg is part of St. Louis Music, which is part of Loud Technologies. Before St. Louis Music, they were owned by Magnavox for a number of years. I think some version or other of the SVT has been in continuous production since the '70s.

They changed them from 6146 output tubes to 6550As, back in the early 1970s, I think the amps with 6146s had some reliability issues, but the 6550 ones are solid workhorses.

 

The 6550s are what causes the trouble. The 6146 was fine as long as the amp wasn't grossly overdriven, which bass amps usually aren't, but they were used in nothing else in the music industry, so the 6550 conversion was done. I think Wyman got more than a decade out of his original six 6146s.

The conversion apparently worked with one particular 6550, but most are overstressed and die early. Exactly what would need to be changed to make the tubes live a normal life, I'm not sure. It may be a screen grid dissipation issue, a bias issue or simply most 6550s really don't like 600 volt B+. The 6146 usually runs 800 volts and occasionally the full kV in Class C RF service. They were hugely popular in two-way and ham radio.

Any changes are probably going to reduce power output a little. Whether this is all that bad or not I'm not sure, but I doubt it. Then again for a touring band three sets of tubes a year is not a major expense as compared to everything else.

 

Further to Doug's point, room lift is 6 dB per octave. Sealed speakers drop that exact amount below the point the cabinet is tuned--a match made in heaven. Ported drop 12 dB per octave below the tuning of the port, which means, though they will stay flat longer, once they drop, they drop out quicker. I don't know about horn loading off hand.

That's one reason why speakers that are say -3 dB at 60 Hz can sound kinda full range-ish. They get a good amount of help (especially sealed speakers) from the room boundaries.

But the other thing is we hear the pitch of low bass notes through the harmonics. Lowest note on an electric bass is 42 Hz so the first fundamental is 84 Hz so if the speaker goes down to 80 Hz, you will be getting musical info from the bass in rock music.

Still, "full range" in modern audio certainly means more extension than -10 dB at 45 Hz.

As far as the 30" woofer, the Electro-Voice Patrician (with some Roman numeral after it) used it. The originals used 15". Cabinet was licensed from Klipsch.

 

... probably the one I bought at a garage sale ... Recored w/ Pyle Driver (as used in the trunks of those down-the-highway boom box road warriors ... Thump, Thump ...) ... yes!

I love it now, the box is still relatively tight and now "only" needs 150 watts to make the windows vibrate ... and it is now the bass sub woofer for my Maggies ...

Steve: Maggies, as you know, need "current dump" amps (like that old Pioneer QX-949) or higher power-MOSFet amps ... a half-horse for each channel is about right >> mmmmm, good!

 

This thread sure lost its excitement.

 

But is it neutral?

 

No, this thread has had lots of harmonic and intermod distortion.

 

"This thread sure lost its excitement."

"But is it neutral?"

... ...

 

http://news.cnet.com/8301-13645_3-5...sound/?part=rss&tag=feed&subj=TheAudiophiliac

Guttenberg goes all inaccurate again. A regular rant there, as it is (or was) here.

I tend to prefer some amount of transient accuracy over tonal accuracy. As in I owned Linn Kans for many years, that basically have a hump response over a flat response (really strikingly so) and yet are dynamically interesting. (at least the mark 2 ones; the mark 1s were really nasty and colored)

I think it's good that speakers are beginning to be achieved that have a better balance of efficiency, flat frequency and distribution responses, and transient response now. Unfortunately they're still mostly small and 2-way. Anything else still requires Mega-Amps, and the trade-offs are more complex again.

 

Good stuff.

 

Mikey, you hit the nail on the head. Both sides of the so-called accuracy debate accept flat frequency response as the essential definition of accuracy. And it is important. But there are other types of accuracy--dynamics being key to the overall gestalt of the sound, and perhaps harder to get used to than a deviation in frequency response. Also included would be various distortions, artifacts, and noise.