Bill Fitzmaurice

All of this is also well known, having been mathematically quantified by 1940. There's even software that will accurately map it out. For instance: https://www.comsol.com/acoustics-module

He could have saved a lot of time, work and wood by reading a book. Everything he 'discovered' and a lot more has been well known in the professional audio community since the 1950s. For instance: http://cyrille.pinton.free.fr/electroac/lectures_utiles/son/Olson.pdf And while he's identified how some changes in response occur he still doesn't know why.

There was no significant difference between the Fender bass and guitar amps of that era, other than reverb and vibrato. Their bass cabs weren't much different either, which was their main limitation of bass.

IME the best FOH sound men high pass the bass somewhere between 60 and 80Hz, and this is with multi-million dollar pro-touring systems. This does the best job of getting tone through the PA that approximates the tone through the backline. The worst sound men don't high pass, resulting in tone that more closely resembles teenagers $5k subs in their $500 cars than electric bass.

NIce, but contrary to advertising claims isolation doesn't do anything to the sound. Where it is useful is with a very soft stage that the amp would otherwise bounce on. http://ethanwiner.com/speaker_isolation.htm

It's a very good idea, when done correctly. While the stage rig will cover the room with the lows very effectively the midrange and high frequency dispersion is pretty bad. Put mids and highs in the PA for dispersion, pull back the lows on that PA channel so as not to overdo those. The same applies to the drums, keys, even guitars. The PA should be providing a balanced mix throughout the room. The problem lies with bone headed guitar'd players who think that they need to play loud enough to blow out candles at 30 meters. PA isn't about volume, it's about dispersion. Most guitar players can't even spell dispersion, let alone understand the need for it. 🙄

It's the rare room where the bass isn't louder out front than it is on stage. On stage there are boundary reflection sourced cancellations, out front there aren't.

No matter, +/-10% variation isn't going to cause a problem anyway. A low voltage brown out is defined as at least a 10% voltage reduction.

Just to make it more confusing: We loudspeaker engineers don't use watts, we use volts. Power delivered varies with current, current varies with impedance, and the impedance of a speaker isn't constant, it varies with frequency. An average 8 ohm rated speaker will have an actual impedance between 5 and 50 ohms, with the impedance being different at every frequency. At equal volume your amp can be putting out 200W at 50Hz but only 20W at 100Hz. We use volts because they're constant into any impedance load, allowing us to accurately calculate a speaker's mechanical limit. And 1+1 doesn't equal 2. Take a look at Ohm's Law and you'll see why. For instance, 28.3 volts into 8 ohms is 100 watts. You'd thank that 56.6 volts would be 200 watts, but it's actually 400.

The more pertinent conversation is the fact that said 400W rating is thermal. The mechanical limit is perhaps half that. The majority of posters in the thread appear to be unaware of thermal versus mechanical capacity. The good news is that it will sound quite awful if you exceed the mechanical limit.

It indicates that the cab is inadequately braced on the inside, if at all. Aside from being an annoyance the energy expended vibrating the cab walls is energy not creating sound, or worse, it creates unwanted sound. This is an example of a well braced cab: https://barefacedbass.com/technical-information/generation-three-enclosures.htm You may not be able to retrofit that extent of bracing, but even a single brace that connects the center of opposing panels has the same effect on vibration reduction as doubling the thickness of the panels.

Both GB and Norway use the same 230v 50Hz power. The problem is probably the difference in the socket/plug pins.

I did, from 1965-1972. I could see using one today in the studio, or for small club gigs, but that's all. As far as vintage valve gear is concerned the Ampeg V4B is considerably better.

A watt is a watt. What differs with valves is that they can naturally compress the signal peaks, subjectively making them seem louder. You can accomplish the same thing more or less with SS using a compressor, but since that occurs before the power output stage rather than in the power output stage the effect isn't quite the same.

That only works if you have a method of attenuating the amp output, with a device like a Power Soak. You wouldn't do that with any SS amp, since the mechanics of how tubes and SS distort are very different. As for the Dark Glass, what's shown inside the dotted lines is in essence a distortion pedal.

That depends on where it's low passed. I suspect Alex did so fairly high, to eliminate comb filtering. Typically it would be done where the center to center distance of the drivers is one wavelength. With two tens that's in the vicinity of 1.1kHz. If it's done at too low a frequency the lost midrange output could be problematic. It would affect personal monitoring, as the driver that's full range should be as high as possible. The boundary reinforcement off the wall shouldn't be affected.

Yes. The dispersion angle in the mids is inversely proportional to the width of the radiating area. As shown that area is twice what it would be when rotated 90 degrees. Boundary reinforcement from the floor happens when the lowermost driver is less than 1/4 wavelength away. At 200Hz that's 1.4 feet. At 100Hz it's 2.8 feet. There are instances where raising it more than 2 feet or so can be beneficial, as in the case of a boomy cab or stage where you want the lows augmented but not the midbass that produces boom. These rules also apply to boundary reinforcement off the wall behind the cab. Very often what makes for the best sound is the same thing that makes for the best real estate: location, location, and location.

You should always turn the cab up tall. It doubles the midrange dispersion angle.

That does not appear to be Eminence. Most Eminence bass drivers have a large pole piece vent in the magnet and/or an extended bump of the back plate.

Looks good, but rotate the 2x10 to place the drivers vertically. Both you and the audience will hear it better.

With a bit of ingenuity you can find a method of securing the head. In my case I attached two inch high feet to the front edge of the amp that hang down far enough to hook over the front of the cab. Where hearing what you're doing is concerned, especially on a tight stage, tilt back is even more effective than lifting.

This, or something similar: https://www.amazon.com/Fender-099-1832-003-Amplifier-Stand-Large/dp/B00LJY4886/ref=zg_bs_11973191_5/138-0471784-6307153?pd_rd_i=B0891LCND5&th=1

I very much doubt that happened in shipping, if it had the grille would have been bent. Have them re-coned. Once pulled they should be identifiable.

Ampeg is conservative with their power ratings. Where farting out is concerned that happens when the drivers run out of excursion. There are many tens rated at 250w that have no more excursion capability than the 100w rated Ampeg ten. +1. The 410 is the poster child of how not to build a bass cab, as neither you nor the audience will hear it anywhere near as well as those same four tens vertically stacked in a pair of 210 cabs.

That's not necessarily a bad thing, as you can tame too much low end by pulling down the low end EQ.