What Amplifier Specifications Do You Feel Is Beneficial?

[Drgonzonm]

Interesting... why would a 20kHz power spec, or even a 20Hz power spec be appropriate for a bass amp?

Just so you know why I ask, there isn't a bass cabinet on earth that could take rated power at 20Hz... which is why there is a high pass filter included in most of the newer, higher level products. Maybe 30Hz (not that it makes any practical difference, but at least 30Hz is getting closer to reasonable).

About two years ago, I saw a picture of AB2 audiophile tube amp, with a 5 hz lower spec. The OT weighed 85 lbs. The amp was used in theater to get the patrons, a body trembling experience. The speakers were folded horns, something we probably do not want to have deal with in our normal applications

Bass cabinets to take rated power at 20Hz. The technology exists, not sure if you want to build one. See Sonic weapon - Wikipedia for a possible sources and ideas to create your 20Hz cabinet.

 

[BadExample]

The speakers were folded horns, something we probably do not want to have deal with in our normal applications

I don't think we want to schlep the rigging that held up those big daddy's.

 

[agedhorse]

The output transformers don't necessarily have to get bigger to go lower. The other option is to design with a core material and geometry that can support the higher required flux.

 

[beans-on-toast]

Impressive engineering in this studio product, the cab does a true 22Hz.

I had a chance to audition it and was pretty impressed. It employs multiple amps which is a good way to go. It weighs 160 lbs but not something that you move around much.

About $7,000 USD each (Adam Audio S5H Horizontal Monitor - Single - ADAM Audio S Series - Vintage King Pro Audio Outfitter).

Here are the specs: Invalid Link Removed.

 

[agedhorse]

Impressive engineering in this studio product, the cab does a true 22Hz.

I had a chance to audition it and was pretty impressed. It employs multiple amps which is a good way to go. It weighs 160 lbs but not something that you move around much.

About $7,000 USD each (Adam Audio S5H Horizontal Monitor - Single - ADAM Audio S Series - Vintage King Pro Audio Outfitter).

Here are the specs: Invalid Link Removed.

Certainly impressive, what's interesting and technically predictable is the tradeoff for low frequency extension that is made regarding sensitivity (low by bass guitar speaker standards), and that there is certain to be significant processing done on all bands regarding HPF (my educated guess is 8th order BW at about 18-20Hz), limiting and extension eq (F3 compensation).

This is how tradeoff are handled on a (presumably) quality product.

 

[Drgonzonm]

The output transformers don't necessarily have to get bigger to go lower. The other option is to design with a core material and geometry that can support the higher required flux.

I'm an Applied Newton Physicist (fancy name for a dinosaur of a slide rule era engineer). I do not believe the equations describing magnetics has changed much in the last hundred years. (The people at Los Alamos and Sandia are pretty closed lipped) Unless there has been developments Where silicon steel has been replaced with something else on the audio level, the world might of seen improvements in flux handling in the single digits. Changes from E-I transformers to toriodal and c-type, have resulted in great improvements. Changing from copper to silver wire helps (Bill Gates has to take out a loan for some of these). If I had a choice, I would build with Lundaul silver wound C transformers, the same as the audiophile amp builders use but the cost of those babies puts an amp price in the range of a vintage 5D6, Bassman.
But regardless of the transformer. frequency influences the size of the transformer. (check out Norman Crowhurst work) Silicon steel still saturates at predictable levels when frequency drops. SE audio transformers will still be larger than PP audio output transformers for the same output.
So far discussion regarding audio transformers address only one component of the high power amp design. available tubes, set other restrictions.
With the solid state technology, now available, we are able to have 1000w power amps that weigh less than a volkswagen bug.
The search for audio on the low end is finding sources for high wattage, speakers. Where is Dr. Who, so we can convert his Tarsus to a bass cabinet.

 

[agedhorse]

That's ok, my experiences are different than yours, but I am also working with more modern materials and geometries than you are basing your comments on.

 

[BadExample]

Impressive engineering in this studio product, the cab does a true 22Hz.

I had a chance to audition it and was pretty impressed. It employs multiple amps which is a good way to go. It weighs 160 lbs but not something that you move around much.

About $7,000 USD each (Adam Audio S5H Horizontal Monitor - Single - ADAM Audio S Series - Vintage King Pro Audio Outfitter).

Here are the specs: Invalid Link Removed.

I notice they fail to list +/- X db on that frequency response. That certainly doesn't mean it doesn't sound great.

 

[beans-on-toast]

I notice they fail to list +/- X db on that frequency response. That certainly doesn't mean it doesn't sound great.

The manual explains how the DSP EQ is used to set the frequency response of the cabinet to suit the room and your requirements. Basically, the room affects the frequency response, treatments are used in the control room to set it up, the speakers are also tuned. Test equipment is used to measure the frequency response of the room where you are monitoring. You can see the frequenc yresponse plots at whatever scale you require. The DSP has a default EQ setting for a flat response, they call it PURE. What they call flat, I don't know. But you tune the bandwidth and flatness to Your requirements.

Studio monitors and room tuning changes all your notions about how to work with speakers. Maybe some day, musical instrument speakers will have these capabilities. But at present, all this technology is very expensive, well beyond what musicians are willing or able to pay.

 

[BadExample]

Very cool stuff, no doubt Mr. Beans my friend. I wonder how it stacks up to something like a Carvin BRX cab.

Frequency response:
35Hz-18kHz (-5dB), 28Hz-22kHz (-10dB)

Not all like the tone, but most seem to and are floored by the bass response. I don't have one myself, and I've been BBQing Mahimahi and Tuna fillets all night while consuming most of a 12 pack... so I am probably best placed on your ignore list

 

[Korladis]

So I'm sitting at my desk pondering some thoughts for an update of specifications provided, and while there are a ton of possible specs. to include I think many of them are virtually meaningless to the overwhelming majority of players. Of course there are some important ones as well.

Now's your opportunity to state your opinions as to what an "ideal" amplifier spec. sheet should contain. As ideas come up, I may wish to discuss them to be sure we are on the same page.

The one thing I am not going to accept are disrespectful posts however, and this is not (yet another) class D amp debate as the class of amp does not matter for this discussion.

To answer the original question...

I would like to know what frequencies the EQ controls are centered at (or if the low and high are shelving, that's also useful to know). Like "the mid knob adjusts the midrange content" is not useful for me. I know that already from the label. I want to know which mids I'm adjusting, and how much (is it cut only? is it about flat at noon? etc.).

If there's some sort of "contour" or "filter" control or whatever, I want to know how it works.

Is there a drive circuit? If so, I want to know how that works. Not every single electrical detail, but more than just "adds drive."

Power ratings are already on basically every amplifier made, but having THD would be nice. I want both RMS and peak power ratings. Also the power rating if you just throw caution to the wind and dime everything, if possible, would be good (not something usually done on solid state amps, but not uncommon with tube heads).

Through its intended cabs, how loud does it get? Watts are an imperfect measurement of sound. I want decibels.

 

[Korladis]

Oh, dear friend agedhorse, your quest evokes two maxims from my years at university, not quite back in the horseless carriage days:
"A camel is a horse designed by a committee." By the time you publish all the info that people want it'll be a camel, indecipherable to all but ... well, it'll defy scrutiny. But they're sure they want it, aren't they?

"Oh little girl, with your nose pressed against the windowpane of life, there is no jelly donut." This came from an economics professor and it's a really interesting [to me] way to say that you can't always get what you want, even when you know what it is.

I suspect that most people will expect and demand that you provide them with information that will support their prejudices. One quote I encountered recently is germane: "More words explain more, less words confuse less." Author forgotten.

Good luck, Don Quixote.

So a committee designed a horse far more suitable for desert climates than (and also frightening to) regular horses?

I think part of the problem with asking us here is what I call the 'forum effect'. By nature of us being here, TB suffers from a major case of self-selection bias. We're not representative bassists.

As an example, many of us here might be pleased to see a specification that says something like 'High pass filter: -24dB octave starting at 50Hz' but the majority of bassists would look at that and say "I'm not buying a bass amp with no bass, you won't be able to hear the E string".

I can think of similar issues with distortion specs (sometimes more is better, ask an SVT), actual, meaningful power measurements (2000W peak at 1KHz from company A might actually be the same as 500W RMS 20Hz-15KHz from company B but I'm buying the one with MORE thanks) etc etc.

I think that any specs published should come with some prose explaining them. Your problem is neither 'it sounds good so it is good' luddites or self-confessed TB experts, its the dangerous people in between who don't know how little they know. The people that say 10" drivers are punchy or that bass sound waves need a lot of space to develop.

So, in other words, morons.

Tone control frequency response graphs at 1/4 and 3/4 knob rotation. Virtually no one dimes tone control knobs and the various usual methods of verbally spec'ing frequency "centers" are pretty darned confusing IMHO.

My D-180's mids knob has been set on 10 for years.

All I look for it watts (for some
Idea of volume) and the frequency band for each EQ knob, though in general I'd expect these to be similar across various amps.

The rest is do I like the sound more than anything.

You'd be incorrect on the latter expectation. EQ controls differ tremendously across various amplifiers.

 

[Passinwind]

My D-180's mids knob has been set on 10 for years.

Exactly, you set it more or less flat, not at something rarely useful like +18dB.

 

[Old Garage-Bander]

Sartori said:
"So a committee designed a horse far more suitable for desert climates than (and also frightening to) regular horses?"

My reply:
The committee designed a guitar amplifier far more suitable for bass playing than (and also frightening to) regular guitarist.

 

[GreyBeard]

After looking over all this, I think a spec of DUTY CYCLE AT RATED OUTPUT would do a lot a lot to tell us how robust a bass amp would be. Also a short layman's explanation of what these specs mean would be extremely helpful to me. Most of us, myself included, don't have a clue what these abbreviations and numbers on a spec sheet mean.

 

[beans-on-toast]

Very cool stuff, no doubt Mr. Beans my friend. I wonder how it stacks up to something like a Carvin BRX cab.

Frequency response:
35Hz-18kHz (-5dB), 28Hz-22kHz (-10dB)

Not all like the tone, but most seem to and are floored by the bass response. I don't have one myself, and I've been BBQing Mahimahi and Tuna fillets all night while consuming most of a 12 pack... so I am probably best placed on your ignore list

Somehow, I think that I'd take a studio monitor over a Carvin any day.

 

[Korladis]

Exactly, you set it more or less flat, not at something rarely useful like +18dB.

That's what the graphic EQ is for.

When I play SVTs, I do actually dime gain and mids, though.

 

[Al Kraft]

That's what the graphic EQ is for.

When I play SVTs, I do actually dime gain and mids, though.

That's interesting to me because I don't think I've ever dimed any EQ knob/slider. I've certainly un-dimed extreme lows or extreme top end though, as well as to notch out an occasional offending feedback/booming frequency.

I'm not afraid to boost that much, but I guess I usually like the inherent voicing of the amps/cabs I play with enough that a change that radical wouldn't appeal to me.

As for gain, I'm a fairly clean player so enough break-up that I get warmth through natural compression and some added harmonics is about all I go for. I always wondered if anyone used that last 30-40% I never get to on a gain control....now I know!

 

[BadExample]

Somehow, I think that I'd take a studio monitor over a Carvin any day.

Ha! Yah, I didn't mean as an alternative, just the frequency response. I don't think you would generally want to use a cab designed for loud live stage use for a professional studio. I worded that poorly, but I did use a disclaimer!

 

[kittywithabanjo]

I'd like to know know where flat really is right off the bat. Which isn't to say you change what your doing just provide the setting that provide the flattest response as I think it will help understand the eq.