Ashdown little stubby "live".

[Rip Van Dan]

Ive got the PF50T, I use it with the older 1990's Ampeg svt-15E and or SVT-210HE, kicks ass. I also have an American made Crate "Palomino 32". Its a 30 watt guitar tube amp. I disconnect the guitar speaker, and run the out to my 15E. fat tube tone(think Zombies "Time of the Season" song)

Wow man, I'm really feeling old. I played that song in my high school group when it first came out in 1968. Played with a group called the "St. James Infirmary", which was named after a song about an insane asylum...was fun! I was playing a 1965 Jazz Bass through a 1966 Fender Bassman at the time - sounded great.

Just tried playing it with my '83 Jazz. It has 70's era pickup spacing so it's a little brighter than my '65 was, but I rolled the tone down to #4 (nice to have numbers on my control knobs) and at least through my Bose headphones, that was the sound.

 

[Rip Van Dan]

To get a more accurate understanding of how this works, there are some other things we need to consider.

The graphic says Concert = 110dB and I am claiming 30W into a 97dB 1W1/m speaker produces 118dB. This suggests 30W is plenty. What is not being said is the sound is loudest close to your speaker and decreases by 6dB for each doubling of distance. The 118dB is measured at 1m.

Here is the progression:

1m/3.3' = 118dB
2m/6.6' = 112dB
4m/13.1' = 106dB
8m/26.2' = 100dB
​

Another consideration is our ears do not have have equal sensitivity across our hearing range. Our ears are most sensitive to high mids. For equal perceived loudness, frequencies below 100hz have to be way louder than high mids.

The Fletcher Munson curves show this.

A phon is a measure of perceived loudness, VS a decibel which is a measure of actual loudness. Notice the phon level equals the dB level at about 1,200hz, but at other frequencies they are not equal.

What this chart shows is the ear is most sensitive at about 3.5khz-4khz, and it is far less sensitive at low frequencies. For equal perceived loudness you need higher SPL at low frequencies (especially frequencies under 100hz).

For example, you need about 127dB at 60hz for a perceive loudness of 120 phon. At 1khz 120dB is perceived as 120 phon. At 3.5khz you only need about 105dB to produce 120 phon.

For the record 300W into and 810 produces calculated SPL of about 125dB at 1m (think Ampeg SVT and 810). 100W into a 412 loaded with Vintage 30s produces about 126dB (think Marshall half stack. So the guitar is actually louder and Fletcher Munson makes the perceived difference even larger.

Great stuff Wasnex. I hate to say my hearing sucks at anything over 3Khz at normal levels. Works fine until 3KHz and then sinks like a stone to the bottom of the graph and stays there. Very definitely a result of my touring in the early 70's playing about 250 nights a year for 3 years standing too close to a very loud amp without using ear plugs. Don't follow in my footsteps because I really stepped in it!

 

[Old Ozzie Guy]

I know this is old thread, but it just popped up, and I thought I would let you all know what I ended up with.
A few years since I asked the original question. I now have a Pf50t, and a TT800. My speakers are Bergantino NXV series 2x 210s, and 2x 112s .
I couldn't be happier with both heads, and the Bergs. I gig about 15 times a year, about half are smallish venues, the others are larger outdoors . With what i have, i can cover any gig, with what i think is a great sound. . I'm grateful to all you folks at TB, for an excelerated learning curve on bass gear.