I have been saying the same thing for years. In this case even in a professional setting. But people don't seem to believe it.
Getting the speaker parameters close to these tolerances is practically not possible. Which only further drifts over time even.
Like I already said before. If people are looking for these tiny little details in measurements, you're looking for the wrong things.
We all should clearly hear +/-0.5dB difference with EQ at 2K when used ABX switch, while even the slight head movement affects the frequency repose easily more than +/-1dB. I still think Toole is right about acoustic compensation in the brain, and I don't think accurate naked frequency response of the speaker is not important. +/-0.5dB correction makes sense in long term in my experience.
If you measure, ever fraction of a dB counts. Anyway, even if you got your measuring microfone fresh from the calibration service and dial in the correction, you have the the first +- 0.5 dB tollerance included. So right from the starting point there is a margain of error. I don't ignore this, but try to be realistic. When I'm building something as subjective as a speaker, errors are part of the hobby (or profession).
Maybe some who go over the top here, dB-wise, should remember that two different speakers, even as they have an absolute identical, measured frequency response, will still "sound" quite different. Just as a linear speaker does not automatically sound good. Speaker building is not that easy...
Maybe some who go over the top here, dB-wise, should remember that two different speakers, even as they have an absolute identical, measured frequency response, will still "sound" quite different. Just as a linear speaker does not automatically sound good. Speaker building is not that easy...
Some info on mics here: https://www.audiosciencereview.com/...crophone-1-2-1-4-vs-class-2-calibrated.23362/
Found some pricing for free field measurments:
http://nwaalabs.ipower.com/our_services.html
Standard "Full Sphere" measurements (360 deg X 360 deg):
5 degree Resolution Per Item: $1550
the facility is... impresive.
http://nwaalabs.ipower.com/our_services.html
Standard "Full Sphere" measurements (360 deg X 360 deg):
5 degree Resolution Per Item: $1550
the facility is... impresive.
FWIW, I do, too. But it’s temperature controlled and y target temp is 70 but with swings from 65-75 degF.
EASERA is used as well - better graphical results with it than other software IMO (including Klippel). (..excepting the near real-time waterfall's of WinaudioMLS.)
I'm surprised they haven't gone to 30 (*or perhaps 59 for a half hemisphere at 3 degree increments) mic.s to reduce the amount of time for full polars..
*they actually have the facility height for it to get a full vertical range on one horizontal sweep.
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I think it's even worse than that: my guess is many don't do linear freq. measurements at all (for a single driver on any given loudspeaker or the loudspeaker itself) - they just pick from the same batch (for the particular driver) after it's been rub/buzz tested (with perhaps a few taken out of the batch-line for an average result estimate for those that did pass the rub/buzz test). This is irrespective of the cost of the loudspeakers.
I think people may be losing sight of what contributes to quality in an engineering sense and what contributes in more of a marketing sense. Although the latter certainly has value it is different. If a third party buying drivers from a manufacturer wants matching of a particular kind then they can have it but they will be charged for it. Some third parties do the testing themselves which is generally more expensive but safer and will return the out-of-spec drivers but the tolerances will have been agreed with the manufacturer. DIYers have always tended to get what was left over which is quite often in the tails of what is deemed acceptable in terms of tolerances having been tested and found to be out of spec for a particular use. Since many of us are then going to use passive crossovers with all the substantial variations this introduces it is not an unreasonable thing to do.
Here is an example of a modestly priced modern speaker where engineering quality has received more than marketing attention. Note the use of an active crossover and the bank of trim pots to handle the inevitable variations due to tolerances.
Here is an example of a modestly priced modern speaker where engineering quality has received more than marketing attention. Note the use of an active crossover and the bank of trim pots to handle the inevitable variations due to tolerances.
What you're saying about the left overs is totally not true. They come from the same manufacturing line for at least 2 decades.
In the very very old days they did have very specific models for the diy market. These days you sometimes can see specific different OEM variants.
In my professional experience as a loudspeaker designer for several companies. You just get speakers in bulk on a pallet. There is no matching involved except for some production testing by the manufacturer. But often these tolerances are a lot higher. Even by the high-end manufacturers. Whatever that even means.
That speaker you've showing is rather dated. From a technological standpoint. Old hardware. Trimpots are not a thing anymore these days with DSP's. Trimpots also don't do much for most active filters practically speaking. Few exceptions here and there.
I do totally agree with you that people seem to forget to making a good speaker is more than reproducing graphs.
But I already said that before.
Not sure I wholly follow the logic. Yes manufacturers tool up to produce drivers in batches, they are delivered on pallets, and there is likely more chance of drivers being close from the same batch but you haven't said what happens to drivers falling outside a client's tolerances whether measured by them or the manufacturer. Or are drivers no longer measured with some being rejected?
Your companies may not have paid for testing but other companies do. Or are you stating this is not the case or no longer the case?
The age only reinforces my point (and if you are aware of a similar link to a more modern speaker design that would be useful). Quality engineering means designing to handle tolerances and adopting engineering that supports doing this. This approach to engineering quality adopted by Sennheiser/Neumann/K&H (and likely one or two other companies) is open to DIYers. Perhaps more so given given the level of attention/time afforded a typical design by DIYers.
That really depends.
Many companies do some global fail-pass system.
Most of those systems are relative (and simple) measurement systems.
Good enough to see major problems, not good enough to estimate this kind of precision.
Often dived in an electrical part, and a acoustic part.
Although with DSP's these days, some companies skip the electrical entirely.
Some companies also only do a quick listening test, without any additional measurements.
Testing from the manufacturing itself?
I have never really seen this, not even by many high-end companies.
They mostly do it themselves. Paying the manufacture for this would be really really expensive, unless you're producing in really high numbers or have a very specific production line.
Although at that point this whole thing isn't usually important anymore at all.
btw, they are not "my" companies, I worked for (many) companies, and still do as a contractor (or directly)
Why would a link to more modern speakers be useful?
If you know how a DSP works and what parameters are important in analog active filters, you should be very ware about what I am referring to?
Which brings me to a much more important point.
Am I talking to someone who things he knows how it works, or someone who has at least a couple years of (professional) experience in directly dealing with these kind of manufactures as well as system integrators?
Because I will be extremely interested and fascinated about discussing certain production techniques from people with experience and knowledge in the field, or maybe run their own company for example.
I am not very interested in defending my years of experience to people who just think they know what they are talking about and doubt any expertise and experience from experts.
Having to explain extremely small basics, makes me already think of a certain way, but I could be also misreading things here.
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To avoid the criticism of being an old design. Neumann is useful as an example because, unlike any other company of which I am aware, they have put out data on tolerances (no doubt because it is in their interest to do so like their relatively detailed specs). Another example is at the end of this review. Since I am looking to start a website on loudspeaker engineering citable engineering information of this kind is useful and fits in with the preceding discussion on measurement tolerances.
I am a qualified acoustical engineer that has mainly dealt with companies from the high and medium tech engineering industry over the last 45 years rather than low tech industries like loudspeaker manufacturing. My interest here is purely as a DIY hobbyist rather than in any professional capacity but being an engineer from relevant fields obviously informs/influences how I view things.
I don't have much interest in production techniques beyond general knowledge and knowing how they might influence the quality of drivers I would buy for DIY projects. Now I am semi-retired I will almost certainly run my own company and there is even an outside chance I may get involved with loudspeakers (is mixing hobby and business wise even when semi-retired?) but the production side would be handled by others. Not my speciality and even if it were chatting about it on social media is not something I would be looking to do.
The main tolerances in any analog active filter are the capacitors.
Resistors are available in 1% and even easily in 0.1% these days.
A tirmpot not only adds additional labor in tweaking (say at least 15-30 min of labor), it also adds additional errors out of the box (aka when not being used). Capacitors are usually around 5%, although better ones exists but aren't cheap.
Depending on the type of filter, but very often it's the relationship between the capacitors that count for the Q-factor of a filter.
I am not gonna explain to people why that is, because for people with experience I already assume you know these things. But for people who are interested, this website is a good start;
https://www.linkwitzlab.com/filters.htm
I understand you pick Neumann, but that is just cherry picking.
That is most certainly not representative for the whole range.
In fact, they are one of the few companies who understand basic things like directivity.
Anyway, going digital removes this whole extra step.
Depending on the complexity of the filter will safe you something like 10 bucks on labor on every speaker as well as skipping the need for a (extra) technician.
Which is quite significant, considering the price for a DSP.
Great, but why bringing things up than?
That also still doesn't explain any experience with production btw, and or how production companies do their quality checks.
If you have been that long in the field you should also know that the quality of a product depends on the entire chain.
I understand that you're not interested in production techniques, but as an engineer you have to take this into consideration.
Hell, this is sometimes as simple as why certain manufactures use certain brand drivers or not.
Not just because they are better in raw performance, but because they fit better in the whole production process.
Maybe they fit their BOM price better, or maybe they just don't want ANOTHER supplier in their chain.
Going back to your original comment (which I agreed on for the most part), and what is MOST CERTAINLY important for this thread, is that it explains the importance of the engineer.
And this little conversation shows that an engineer needs to take an awful lot more into account than just making the best performing loudspeaker.
Something that the vast majority of people here don't seem to have any experience whatsoever.
Which is more than obvious if you only pixel peep speaker graphs for nitty witty details and forget about all the other things.
If people here want to improve their skills and knowledge in building better speakers, you're looking at the wrong thing.
Anyway, I sometimes get the feeling that people don't want to hear any real in-depth information.
Or why they are even on these forums with questions to begin with?
Because as soon as some people with experience try to explain things, some of you get all offensive.
Rather strange approach if you want to understand more about stuff?
Look, I'm sorry for such a confrontational post....
but would you please get off your high and mighty platform...
there's a lot of folks on these forums with brains and experience too ...that no doubt understand things you don't....unless you're saying you have it all down pat
I for one feel humbled that b_force has been willing to descend here but being blinded by the light I now realize that I am not worthy to fly this close to the sun.
I find it a very silly an childish way of looking at people like that, excuse my words but I lack the proper English words to say that on a different way.
If you think that's what it's all about what I am writing, I would highly suggest reading my stuff again.
But this time without emotions please, but trying understand what I have to say.
No I have never been on a high and mighty platform, nobody is, not one single person knows it all.
But what I do, is check what people's background is, respect their experience and knowledge in that and ask objective questions accordingly. If people have years of experience in a certain field, made their hands dirty know the business and all, I fully trust and respect that. If I have something wrong, fine we will discuss it and I will adapt accordingly.
But guess what, with the vast majority of those people there are hardly any debates like this.
Yeah we discuss details sometimes, but not basic fundamentals.
But what's happening very often, is that people even refuse to respect and clearly doubt any kind of professional experience from people with decades of professional experience and knowledge.
That doesn't have anything to do with a "high and mighty platform", that is just being extremely disrespectful.
Hi b_force,
There's no emotion in what i said. It's simply not that important to me. Sometimes, an honest rebuke is an honest friend.
I've read your stuff.....must say it seems to be more about claiming credentials and experience, than providing hard info.
Although that said, at times you do bring good info to the party. 🙂
Background, credentials...??? yeah, good luck with all that...
(if you knew the circles of lofty academic & processional credentials & backgrounds I've circled in, and even hold , .....you'd understand my skepticism)
Unfortunately for credentials, the world looks to how are you hitting today.
It may honor and pay ceremonial tribute to credentials and backgrounds;
but respect today, nods of understanding agreement, and bets on what is correct, are made based on today's performance.
So show us what you have that helps, what is currently salient, and moves us along...OK?