sensitivity or frequency response for cabs?

[bottomzone]

I realize the importance of measurements, including frequency response, sensitivity and efficiency as they relate to loudspeakers. However, the most important thing to me as a bassist is how does my bass sound using amp A and speaker B. As an example, even though my Schroeder Mini 10+L has a higher listed sensitivity rating (102 dB SPL 1w/1m) than my new Phil Jones 6B (95 dB SPL 1w/1m), the 6B sounds better. Also, I don't need as much volume to be heard. Whatever standards that Phil is or is not adhering to, he's doing it right as far as my ears can tell!!!

A Groove is a Terrible Thing to Waste!

 

[will33]

I think part of the issue here is that the measurement and calculation method is not stated. Within this industry, I would expect (or maybe wish) that a specification covered by the AES/IEC standards would be quoted without citing the standard. The assumption being that if the method is not stated, it adheres to the accepted standard. If an alternate measurement or calculation is used, such as averaging sensitivity over the LF and MF domains, this should be stated with the associated specifications since it deviates from the assumed standard. Of course, if I produced bass amplification equipment, I would not sell anything before having generated many detailed response measurements. Then, I would definitively state which standards I followed in testing. This is no different than when I test the instrumentation I design (day job) for saltwater corrosion resistance per ASTM test specifications. The results I come up with are stated along with the standard I followed to perform the testing. One of these is an acoustic sensor, so I follow acoustic standards for oceanographic sensors here.

Caveat: The assumption that quoted specs on bass guitar equipment adhere to AES/IEC standards is not a good one in many cases.

Bill and agedhorse, I appreciate both of you being present in this forum equally. Without the ability to discuss technical matters with experts like yourselves, I wouldn't visit this forum nearly as often. I hope that discussions like this are carried out in the interest of professional discourse and debate, rather than personal vendettas.

agedhorse is providing specifications and measurement methods here, which is well beyond what most of the industry provides. Whether or not the methods are as prescribed by the AES/IEC standard, he *is* stating what the methods are. This method is employed because it is believed to be a better representation of real-world performance to a bass player. The intent here doesn't seem to be circumvention of an industry-set standard to inflate specifications.

However, since neither AES/IEC standards or the altered measurement methods used by agedhorse are understood by the average bass player, it is no longer an even playing field. Perhaps unintentionally, this is deceptive to the typical consumer in the bass industry, since the assumption is that these specs adhere to a standard and can be compared. There are many reasons for standard measurement practices to exist and be followed, even if they may not tell the complete story in your particular application. The bottom line is that they provide an objective, fixed method of comparing a wide range of equipment.

Where the musical instrument industry (and bass industry specifically) have failed is in educating customers about what *actually* works well in a bass amplification application. This doesn't mean every bass player has to understand the engineering principles behind the measurement and design. It just means that bass player should probably understand that response down to 30Hz and ultra-flat broadband response isn't usually what he/she actually likes or requires. Further, it's rarely what he/she is actually getting from equipment that claims to possess these attributes. Rather than deceiving ourselves and others into thinking that this is required, the industry would be better served by objectively communicating what actually works for bass within the greater context of professional audio equipment and the associated standards.

Within that context, the best approach is to follow AES/IEC standards of measurement, state that these have been followed, and educate your customers on why your specifications might not be comparable to others that were not generated using the standard. Otherwise, you may as well not generate any specifications, since there is no basis of comparison if you are the only one using your method. This defeats the purpose of specifications entirely, since it is impossible to use them for comparison.

If every manufacturer would just post a half-space frequency response plot generated by following AES/IEC standards, one could compute one's own sensitivity numbers for any particular frequency band desired. Even this would only tell part of the story until one started factoring in phase response, group delay, dispersion, displacement-limited response, etc. But even a frequency response plot would be a drastic improvement on what's out there today.

All of that aside, the last thing I want to see is either billfitzmaurice or agedhorse leaving the forum because the discourse here gets ugly.

Well said, especially the parts where players need to understand that 31hz is not required, and often not desired, to have a solid low B.

Again, it all comes down to putting out more comprehensive information while at the same time educating players as to why this is better than that, etc. Why your company A is superior to company B even though their numbers are higher or lower or whatever. With standardized test methods, all it would take is one company putting out their info, along with the same info on the competitors products, bought off the shelf, to describe why theirs is better. Even if the test methods where a little off, we could argue about that later, as long as they were all the same.

 

[seamonkey]

...
All of that aside, the last thing I want to see is either billfitzmaurice or agedhorse leaving the forum because the discourse here gets ugly.

Invalid Link Removed

"Science works because scientists disagree. They challenge each other's ideas, find better ways to interpreting the data and eventually come to conclusions that bring us closer to truth."
Maggie Koerth-Baker May 28, 2010

 

[billfitzmaurice]

even though my Schroeder Mini 10+L has a higher listed sensitivity rating (102 dB SPL 1w/1m) than my new Phil Jones 6B (95 dB SPL 1w/1m), the 6B sounds better.

Law #1 of loudspeaker design: Higher sensitivity is always obtained at the expense of low frequency response. Law #2: When a single woofer direct radiator speaker is rated more than 98dB your BS alarm should be ringing at 110dB.

Going back to the OP's original question so many moons ago, honest measured SPL charts level the marketing playing field and take BS claims off the table.

 

[dj150888]

Law #1 of loudspeaker design: Higher sensitivity is always obtained at the expense of low frequency response. Law #2: When a single woofer direct radiator speaker is rated more than 98dB your BS alarm should be ringing at 110dB.

Going back to the OP's original question so many moons ago, honest measured SPL charts level the marketing playing field and take BS claims off the table.

Genuine question Bill....is the "Law 1" dependant on the box staying the same size, e.g. if we have box 1, x cubic feet in volume, y sensitivity, would box 2, with x+n cubic feet in volume, and also y sensitivity, potentially have a greater low frequency response?

I like to learn about these things, its something I genuinely don't know about very well and I'd rather ask and look stupid than not know the answer.

 

[Jerrold Tiers]

Very interesting.......

To be truthful, I very much doubt whether most of the specs are useful...... The sensitivity might be generally useful to act as a tie-breaker as to why one cab sounds weaker...... And the power handling may assist in selecting a cab that probably won't be vaporized by your amp. But the rest of them are probably BS no matter how scientific the methodology.

Why?

One good reason is that the "standard space" often doesn't exist........ Players may be in an effective half-space (at LF only, of course), or in a quarter space but at a distance from a hard wall that creates destructive interferences in bad places..... even in a 1/8 space, The LF performance and response will be radically different in each location. What price response curves? the bar owner says "you set up over there"... and you do.

I am sure that it is nice to have a standard AES measurement...or whatever but don't make the mistake of thinking that specs will help you decide if you will like the cab. That is almost impossible.

Take the AES sensitivity.... very scientific, best of engineering principles are used, etc, etc.

And it is nearly total BS......

Because the effective loudness to your ear is going to be affected by a considerable amount of the 'forbidden zone" frequencies. yes, yes, this is in the frequency response.... and maybe that works. But speakers have "bass character" or "PA character" (which is a lack of any character), "guitar character", etc.....

The entire system, from the strings to the cabinet, is the instrument.

This is distinct from PA, where the system and each part, should ideally be just a 'window". Then each part can be judged for it's clarity, and there is no silliness to that concept.

IMO, it is totally POINTLESS to separate the speaker from all other parts of the "bass instrument system", and analyze it with any hope of getting a sonically useful result. That is like trying to judge an acoustic guitar by taking the character of the bridge, and the bracing, and all the other parts each individually, producing specs for each of them.

Clearly the total is what is wanted, not pages of component specs. While teh total may be possible to obtain by convolving the responses of all the parts and pieces, that is not useful to a person who wants to buy a guitar and simply try it...... THAT "convolution" is the one that has meaning..... the reality-based one, not the "synthetic" one.

The bass player has the advantage that he or she can actually assemble an "instrument" or at least an "instrument system" from modular parts. But it is not clear at all that just any arbitrary set of specs and procedures are applicable to that assembly.

A particular speaker suits a given amp, and bass, better than others. the specs do NOT tell you why, or how, that happens, and they cannot yet help you to predict whether you will like it.

The AES specs are ever so nice... for PA, which has a totally different task from a bass instrument speaker.

The reality of the usage does, or should, trump the "scientifically neutral" approach, unless and until there are more suitable standards for doing specs. The fact that so many don't do consistent specs, yet are successful, is an indication that the approved methods don't necessarily measure in useful ways. or it could be that people just don't measure that way from lack of equipment or a gut feeling that "that isn't what this is about".

When I first arrived at SLM, which was prior to Ampeg being bought, I was the only "engineer" there. My boss had designed everything up to then.

The guitar and bass amps, which were then only Crate, had been designed so they mostly defaulted to a "flat" response. Nobody was very excited about that, and I very quickly fixed that problem. Flat responses and musical instruments usually don't go together very well, although tastes vary.

We didn't find many people who preferred the old "flat" response to the "pre-eq'd" response of later products. In fact, after that every product was always pre-eq'd, just as every old Fender amp in the entire world is pre-eq'd............

Nobody seems to care if a violin or acoustic guitar has a measureably flat response.... What is important is that it SOUNDS "even", without obnoxious peaks..... even if the actual "output" is anything BUT "flat". And the measuring instrument with the last word is the ear.

The engineers clearly should know the details of the speaker. And some set of specs is appropriate to publish. if the publisher of those is up-front with how they are obtained, all is well.

The market for bass speakers won't punish a builder who has a good product, even if their methodology offends the PA-oriented purists. Maybe one of those "maverick standards" will turn out to be useful for spec production on bass speakers.

Edit..... With regard to players and tone.... With the "bad old flat amps", we noticed that two players, extremely good players, got excellent tone from the "bad" amps..... They were the only ones.

There was a claim by some that "if the best players can get a good tone, there can't be much wrong with the amps, just with the other players". This was eventually resolved by noting that nobody else could do it, and those two were a very limited market........ We needed to make amps that lots more folks could get good tone from.

That has application to bass speakers, and specs, etc. Some "systems" (instrument, amp and speaker) seem to just "have" good tone. Others you can "get" good tone from. Still others are too much work to mess with, even if it could be possible to get what you want. That varies with the player... I am not a good player, and I work at decent tone with systems that others have no trouble with..... in fact I have been around so many good players that I have been thoroughly 'run off"....I just play for my own amusement anymore......... I'm not quittin the day job......

I have yet to find any speaker spec that can provide ANY insight into that problem........ ALL specs have to be regarded with suspicion unless they can be as relevant to the bass speaker and system as the existing ones are to PA. And make no mistake, the existing specs are GOOD for PA stuff, and other "reproducers" of sound.

That "goodness" for PA does not necessarily translate to a relevance to bass, where the best "reproduction" is not the sole goal.

 

[rpsands]

Um, if what you want to come out of your speakers is what would go into the PA (post-eq), having a flat frequency response under load is both desirable and fairly simple to get close to.

Me, I like what comes out of my speakers to be as close as possible as to what my post-eq sound would sound like through reference monitors or a nice balanced PA.

Not everyone wants that, but lots and lots of people do.

 

[JimmyM]

Um, if what you want to come out of your speakers is what would go into the PA (post-eq), having a flat frequency response under load is both desirable and fairly simple to get close to.

Me, I like what comes out of my speakers to be as close as possible as to what my post-eq sound would sound like through reference monitors or a nice balanced PA.

Not everyone wants that, but lots and lots of people do.

lots and lots? you grossly overestimate. if lots and lots wanted it, then more manufacturers would make it. plus your assumption that pa's are flat response is a fallacy. you've seen the graphs of current speakers. haven't seen a single one that's got truly flat response, even those reference monitors or a nice balanced pa. there's always something in there that will screw the pooch.

oh sure, they SAY they want it because "transparency" was a big buzzword for a while. but then they'd say stuff like, "i want a transparent rig like eden." EDEN??? HAHAHAHAHAHA!!! or they say things like, "tube amps are colored and ss amps are uncolored." in what universe does that happen? again....HAHAHAHAHAHAHA!!!

most people wouldn't recognize flat response if it bit them on the nose. me, for example. i consider myself to have very good ears. but it took me years to recognize near flat response, and to be honest, i still don't believe i could recognize it. every time i think i recognize it, i find out i'm wrong. i can recognize what sounds like flat response to me, but invariably i'm always off if you scope it. besides, what bass has flat response? a precision? an alembic? a modulus? a hofner hollowbody?

so while some people claim they want flatness, the vast majority really don't. i used to think i did, until i discovered what i thought was flat was anything but.

 

[R Baer]

Luckily there is a vast array of cabinets to choose from out there, so I think everyone really has the ability to find a flavor that works for them. I don't think it should be considered a fault of those of us in the amplification industry that we choose not to make a bass cabinet that sounds like a PA cabinet. iMO, there are already a number of PA cabinets out there that do a good job of that.

There's no reason you can't use a PA speaker in your rig if that's the sound your'e after.

 

[alexclaber]

I'll never understand why anyone would talk about an instrument not having 'flat response' and use it as an argument against accurate amplification. An instrument is like someone's singing voice, it is the source of the music. Some singers prefer being unamplified, some like to run through highly accurate condenser mics and expensive solidstate preamps, some like more coloured condenser mics and more interesting sounding tube preamps, some even like to record through highly coloured dynamic mics and through heavy compression and so on, and everything in between.

Same for bass guitar.

You can't have an instrument with 'flat response' because 'flat response' describes there being no change in response between input and output. The instrument/player combo is the starting point, there is no input!

Horses for courses. If uncoloured response was never a good thing there wouldn't be so many pro rigs with an Avalon U5 running DI'd into the PA. Whilst if coloured response was never a good thing there wouldn't be so many pro gigs where the cab is miked.

Once you figure in the ability of the player, the bass, the strings, the pickups, the onboard EQ, the preamp gain, the amp EQ and so on to control the final tone coming out of the rig it seems fairly obvious that specs cannot describe tone. They can however describe output ability, part of which is the ability to maintain consistent tone at higher SPL. Any bassist worth their salt should be able to get a workable tone from most rigs if the rig has enough output potential - but if the rig can't play loud enough then they will struggle with tone as well as volume.

 

[JimmyM]

maybe i'm just a poor communicator. point taken about the instrument being the source. but i do think that those who want a true uncolored response are in a pretty small minority, even if they think they do.

still, as roger said, there are plenty of options out there for those who want to get close to it, and i don't think it's necessary for bass players who don't necessarily want it to see the entire spec list. i do, however, support the idea that they shouldn't lie in the specs they do provide.

 

[tom-g]

+1

The argument is about the cab being uncolored. This gives you, as stated before, as close as possible a signal to the PA as you have on stage. Of course the whole system is colored by the bass, eq on preamp, power amp, etc.

It gives the option of being more in control of the one's sound.

 

[JimmyM]

+1

The argument is about the cab being uncolored. This gives you, as stated before, as close as possible a signal to the PA as you have on stage. Of course the whole system is colored by the bass, eq on preamp, power amp, etc.

It gives the option of being more in control of the one's sound.

i get that, but what cabs out there are flat? even bill fm's cabs aren't dead flat.

 

[tom-g]

Beats me. I don't have any specs I can trust.

Edit:
I am aware that no cap is totally flat. But there are (must be) some that get close.

 

[thudfromafar]

i get that, but what cabs out there are flat? even bill fm's cabs aren't dead flat.

no girl is perfectly beautiful, but some are more beautiful than others

 

[alexclaber]

i get that, but what cabs out there are flat? even bill fm's cabs aren't dead flat.

None. But one that is designed with the aim of getting closer to flat response plus being less coloured in other aspects will sound a lot less coloured that a cab that has been designed to have a certain sound, or (worst case scenario) has barely been designed (in an engineering sense) at all!

 

[12bass]

...
Because the effective loudness to your ear is going to be affected by a considerable amount of the 'forbidden zone" frequencies. yes, yes, this is in the frequency response.... and maybe that works. But speakers have "bass character" or "PA character" (which is a lack of any character), "guitar character", etc.....

The entire system, from the strings to the cabinet, is the instrument.

This is distinct from PA, where the system and each part, should ideally be just a 'window". Then each part can be judged for it's clarity, and there is no silliness to that concept.

IMO, it is totally POINTLESS to separate the speaker from all other parts of the "bass instrument system", and analyze it with any hope of getting a sonically useful result.

This is a view I share. Everything between you and the sound waves emanating from your rig comprises the instrument. All are part of the creation of an individual's bass tone.

In some cases flat, or near-flat, response may be an advantage, but that depends a lot on the sound coming from the bass, the pickups, the strings, the wood, etc.... Some (most?) instruments would be ill-represented by a completely uncolored rig.

 

[fdeck]

IMO, it is totally POINTLESS to separate the speaker from all other parts of the "bass instrument system", and analyze it with any hope of getting a sonically useful result. That is like trying to judge an acoustic guitar by taking the character of the bridge, and the bracing, and all the other parts each individually, producing specs for each of them.

Is it worth bothering with specs such as the Thiele-Small parameters of the drivers? Can those parameters help guide us towards a good design if we understand them and know what to do with them? Or should we simply try every driver in every possible box until we are satisfied?

 

[mulchor]

In my area it is literally impossible to audition bass cabs in stores without driving for hours. But it's quite easy to rent PAs, cabs and amps. I'd guess that you can cheaply rent PA in any medium-sized town.

So if you really think that kind of sound might be the answer for you, it's easy and cheap to try. Perhaps you'll discover a sonic secret. Or perhaps U2 still haven't found what I'm looking for.

 

[Jerrold Tiers]

I'll never understand why anyone would talk about an instrument not having 'flat response' and use it as an argument against accurate amplification. An instrument is like someone's singing voice, it is the source of the music. Some singers prefer being unamplified, some like to run through highly accurate condenser mics and expensive solidstate preamps, some like more coloured condenser mics and more interesting sounding tube preamps, some even like to record through highly coloured dynamic mics and through heavy compression and so on, and everything in between.

Same for bass guitar.

You can't have an instrument with 'flat response' because 'flat response' describes there being no change in response between input and output. The instrument/player combo is the starting point, there is no input!

This resolves to wher you draw a line and call everything on one side "the instrument". I think some are drawing that line in what is for many people the wrong place, and that leads to a total misconception as to what is wanted.

Music is SOUND. It is not an electric potential, etc, it is SOUND, vibrations in the air. The instrument, be it an acoustic guitar, or an electric plus amp and speaker, produces that sound.

The player of an acoustic instrument has an "instrument system" in his/her hand. You do various things to this "thing" and out comes sound, which presumably pleases the musician, or they wouldn't use it.

An instrument that does not produce sound eventually would not be regarded as a great success...... even though that sound output may be possible only through the PA, it still comes out as sound.

So don't bring up electronic synths etc, because they are complete creators in themselves. They need "reproduction" of sound. The PA is a good place for them.

Some may regard their bass as "enough" and they want the output to be regarded like a synth. That's fine, it isn't "wrong" for their wants.

Amps have EQ, some have DSP features, and a huge number of various "effects units" are sold every year. That rather squashes the idea that "most" or even "many" people want the raw output of the electric bass "re-produced".

Some may say they want the bass plus the effects...... re-produced. And maybe they think so.

But since the only way anyone even HEARS (note the word) what those various effects units do is by first putting the signal through a speaker, the speaker is definitely part of the system.

A bass instrument speaker which makes no pretensions to being a general purpose PA speaker is really to be classed as a form of "effects unit".

Unless and until people start judging effects boxes by their response flatness and low distortion, it seems rather silly to require everyone to apply PA standards to bass speakers. That is essentially the same thing, after all.

Does this mean I don't want any basic standard specs applied to bass speakers? not necessarily.....

I do think that applying some specs may be totally misleading..... is a speaker that goes to 30 Hz at -4 dB "better" than one cutting off at 55 Hz because bass is a low frequency instrument?

A lot of "spec nerds" might think so, until they compared that 30 hz speaker with another that is better "voiced" to place the bass in the mix where it belongs. The latter will be louder, and will probably be generally judged to have "better tone".

be careful what you ask for.