Partial volume loss from speaker possible?

[Satchmoeddie-II]

If you get the acoustic phase cancellation just right, it can suck away volume in a very dramatic way. Some cabs are famous for it. Oddly, for some it works out wonderfully well, but for others it is a black hole of tone. Most amp builders were more concerned with $$$$ than ♫♫♫, and they would either not care at all about tone, or find some compromise. I made a neat device that can tell me resonant frequency & harmonic freq's of cabs as well as phase cancellation, & standing wave dead spots. The standing wave & reflected cancellation are both forms of cancellation, & usually a 180 degree cancellation is worst. Placement within a room can account for it too. Plate reverb was just bouncing your speaker's sound off of a large plate to get a natural slap back. If placed wrong some notes were just eaten up by themselves. Usually voice coil issues with low volume are a matter of a partially shorted coil in single spkr cabs, maybe open coils in multi spkr cabs. My last encounter was an 8 ohm that was shorted to about 2 Ω AC Z @ 1KHz or 1.2 Ω DC R. The volume was super low, & when turned all the way up I got a light show around the power tube sockets. I wound up sticking an extra Weber alnico in the amp & it sounds pretty mean for a simple 5 watt SE EL84 practice amp. It is a 1960s Epiphone model 100 1x10" combo I got for $50. It sure stomps the crap out of a Valve Jr. I use a Bruel & Kjaer SPL meter, ADC analyzer, white & pink noise gens, & some home built items for the acoustic analysis.

[Reeltarded]

All good but plate reverb has a driver and it's in another room far away from the noises, God help us.

[Satchmoeddie-II]

It does not matter. If the delay rate is not adjusted right, phase cancellation will counteract certain notes. In many studios a plate was placed in front of the guitar amp or speaker cab & the mics placed so you got a slap back echo. Noise is not the issue. It is phase cancellation. The German Elektro Messe Akoustic had it's own driver, & was usually suspended from the ceiling on a vibration dampening suspension, in better studios. It is often called a "plate reverb". In the old days a plate with good acoustic reflectivity was placed in front of a speaker cab. It is partly the same reason bands would record in large rented houses. Either way, it is not the noise that causes the issues but reflected sound waves that cancel each other out. In rooms with 90 degree corners standing waves were an issue, so splayed walls were introduced for studios & concert halls. It is the same reason B & W speakers went with a nautilus shell shape for behind their larger paper cone speakers and a drawn straight tapered tube behind the mid range cones. Other manufacturers just stuffed the cabs with insulation. You can take tape echo champers, BBD analog or digital echo delays & find delay rates that swallow up certain notes with phase cancellation, whether outright, or partial harmonic content. Our family started in the music business for profit in 1932. I still get old tube EMTs in for repair every year. The new ones are digital. Either one can be set at a delay time that cancels some notes out. It is simple physics. Technically any acoustic situation can be equated to electrical mathematical equations. It is still done, all the time. It is all the study of wave forms, whether in air or as an electrical signal. The newer passive plates I make are honeycomb aluminum sandwiched between fiberglass & a thin veneer of stone.

[Reeltarded]

He mixed speakers though. One broke in softer than the other and now the lesser efficient speaker is basically a round hole plug in a 2x12 cabinet.

I don't mix speakers. I pick one I like and work with it. This is one of two primary reasons not to mix speakers.

[Jana]

I like paragraphs.