Bill Fitzmaurice

The high Z is 4k. A bass amp input impedance is typically 1 meg.

Impedance probably explains it. The Neve is designed to operate with low impedance sources. A passive bass is a high impedance source.

That indicates the hiss is sourced in the power amp section, so it's probably not the mains. It's an inexpensive amp so it may be normal for it.

Beware of the pitfalls of doing this indoors. Some years ago there was a much ballyhooed subwoofer shootout in the States. A dozen or so subs were compared, and the RTA measured results were all quite similar. That's because what they were measuring wasn't so much the individual subwoofers response as it was the room response. If the room has recording studio acoustics you're good, but if it has gymnasium acoustics it may be a futile exercise.

As best I can tell the cab internal volume is about 60 liters, so a 75 mm ID tube 35 mm long would give roughly 50Hz tuning. But the port velocity is off the charts. You need two, 120 mm long.

The video points out that at the tuned frequency cone movement is at a minimum, while port output is at its maximum. However, one cannot assume that 41 Hz gives the best result. That you determine with modeling software. With most bass cabs the best result is around 50-55 Hz. He also gave the manufacturer too much credit on the port sizing. They're much too small. His methodology is off as well. To find the exact tuned frequency you use a sine wave generator, slowly sweeping the frequency until the cone movement is at its minimum.

That diameter is far too small, so you'd end up with port air mass velocity that's too high, resulting in port noise. For two tens in an average size cab with 50Hz tuning the minimum required port diameter is 12 cm, or a pair of 8.5 cm.

If you remove the tweeter and don't replace it with a port of the correct length and area you'll likely make things worse. Getting it right requires modeling, not just to find the correct tuning frequency but also acceptable port air mass velocity. This assumes the driver will work well in a ported cab at all. Many drivers are compatible with both sealed and ported alignments, but those which are ideally suited for the one are not suitable for the other.

If it's loaded with four 16 ohm speakers they may be wired to 4 ohms already.

You can use a bass cab for guitar but you won't get any crunch or compression, let alone anything close to woman tone out of it. The only way you'll get anything other than totally clean is with effects...unless you manage to score a '59 Bassman.

The additional output is roughly 3dB, which isn't massive. If the 210 isn't enough you're better off with another 210. The main advantage to adding a 110 would be the higher position of the 110, making it easier to hear the mids and highs, but you can accomplish that with a tilt back amp stand.

Wrong forum. This is the PA section.

Higher frequencies seldom come from ports at a significant level. About the only time that happens is when a rear mounted port is in back of a woofer, which would be rare, as a port would have to be very short to fit there. When there isn't a direct line of sight through the port to the cone higher frequencies won't come through the ports at high levels. For that matter low frequencies don't actually come through the ports. This goes to how ports work. The air mass within the port vibrates back and forth, the portion of that slug of air that meets the outside air acts like another speaker cone. Unlike a speaker cone it only vibrates at and near the tuned frequency, so the bandwidth of the frequencies it passes at a high level is quite small, on average no more than an octave.

In this case it won't matter by much. Since the woofers only operate up to 800Hz that places their center to center distance within the required 1 wavelength, which is 42cm at 800Hz. There is some loss of horizontal dispersion below 800Hz where the woofers operate, but not enough to be concerned about.

Correct. You want the upper midrange/high frequency elements vertical. With a conventional 210 the tens are the upper midrange/high frequency elements.

If you're not getting huge thumping bass that sounds like an approaching Godzilla or some kid in a ricer then you're doing something right. I've worked with plenty of sound men at the top of the food chain who didn't get it right, prime examples of the Peter Principle at work.

Gut thumping bass isn't the fault of the gear, it's the fault of the person running it. 😒

What matters is the positioning of the tweeters, not the woofers, so you'd stack them as shown in the picture.

What sold me on my BMW 328 GT was room for my golf clubs and my gear, along with rear seat room for adults, with no compromising of performance.

How many of those tests involved measuring the results? The mere fact that you knew the cabs were front or rear ported would have influenced your perception. http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html

What matters is the cab internal volume, not the specific dimensions. As to damping it's required on all the internal surfaces.

It does, but it doesn't matter. Low frequency projection is 360 degrees. That means rear ports project as much sound to the front as they do the back. By the same token front ports, and for that matter the cone, project as much sound to the back as they do the front. Dispersion only narrows to 180 degrees when the baffle width is one wavelength. At 100Hz that's 3.4 meters. At 50Hz it's 6.8 meters.

Consumers are as much to blame as marketeers in that. You can see examples of that with every post where someone comments about 'getting all the watts out of my amp'. Being professional musicians we should all have at least a rudimentary understanding of how the tools of our trade work, but sadly most do not. That could be excused when all we had to go by was manufacturer sales brochures, but that hasn't been the case for the last two decades. The truth is out there, a simple search will find it.

Yes, you may, assuming you've used speaker modeling software to make sure it's compatible with the cab you intend to use it in and will handle the power you intend to use, both thermally and mechanically. The OP did not do so, resulting in his unfortunate experience.

Egg boxes didn't absorb sound, they were used in radio stations and recording studios as diffusion devices. By scattering reflected sound waves they greatly reduced reverb and echo compared to flat surfaces. The shape became associated with improving acoustics, so when acoustical foam came along that shape was adopted. But foam lacks the density required to be an effective diffuser, so from that standpoint there's no advantage to the shape. Foam does absorb sound, with the rate of absorption and frequency to which it does so determined by its depth. Since the depth of the foam is less in the dimples it's less effective than foam with no dimples.