Design speakers WITHOUT any measurements

Hari Iyer

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As the title suggest - i would once in my lifetime try this method of speaker design using only subjective listening with some music. Many have been using this method with reasonable amount of success and there may be some wisdom in their approach. I am a complete noob with this method and will like to learn from experts using this approach (Nothing to loose either).

For this i may keep my measurement mic in lock and key and not measure unless i have completed the speaker design by only subjective listening. This will give me a very good assessment of how much my listening is skewed vis-a-vis the measurement. Having said all this - i dont even know where to start from and will certainly look for guidance from other FMs about their success stories.

Eagerly awaiting your responses.
 
What a topic. Maybe it's more local to you guys? People might keep some of that to themselves as it's so hard-won, but this board is special, too, so who knows? All I know about is what people used to do (before gear prices decreased enough for diy'ers to obtain), but I'm thinking you want contemporary practices. If nothing else, it gives me a chance to post one of my favorite quotes:

"The first step in good loudspeaker design must be to inquire as to the intention of the device."
- Stan White

I know you're interested in the process, but we need a bit of a "spec" (how big, how loud, how low) about what you want to use for your test mule. Size of room where it needs to do that would help as well. Assuming high-economy implicit (?)

And there are degrees of "w/o measurement"--I'm thinking VAC is legal? I'm sure you've seen it, but for those who might not have, Allen's diyA thread on xo's is less a slightly "less-blind" (seat-of-the-pants) approach. Basically how much "winging-it" are you thinking? Are you leaning more toward something to seriously live with or more toward guiding a young person in their first diy efforts (ie simple-simple)?
 
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If primary calculations are done,say volume and size of box using ts parameters, then task is easy. Assemble everything and listen carefully. Then rest can be adjusted according to listening experiments. that is crossover, damping etc.
I remember when l came to listen Kevlar cone speakers in your office, I had suggested that woofer and tweeters are not singing together. Similarly with some other speakers,I couldn't hear good bass and you did remove extra damping. So may be that way you can try.
 
Go for it. The only question that comes to mind is, how would you know and adjust for the limitations of your hearing abilities? I’d imagine each of ours hearing ability is varying, depletes with age and abuse. Is there a risk that you’re designed by the ear speakers might miss on the parts of the spectrum that you don’t keenly listen to? Of course this won’t matter if the speaker is intended exclusively for your own personal listening.

Nevertheless, an interesting experiment.
 
What a topic. Maybe it's more local to you guys? People might keep some of that to themselves as it's so hard-won, but this board is special, too, so who knows? All I know about is what people used to do (before gear prices decreased enough for diy'ers to obtain), but I'm thinking you want contemporary practices. If nothing else, it gives me a chance to post one of my favorite quotes:

"The first step in good loudspeaker design must be to inquire as to the intention of the device."
- Stan White

I know you're interested in the process, but we need a bit of a "spec" (how big, how loud, how low) about what you want to use for your test mule. Size of room where it needs to do that would help as well. Assuming high-economy implicit (?)

And there are degrees of "w/o measurement"--I'm thinking VAC is legal? I'm sure you've seen it, but for those who might not have, Allen's diyA thread on xo's is less a slightly "less-blind" (seat-of-the-pants) approach. Basically how much "winging-it" are you thinking? Are you leaning more toward something to seriously live with or more toward guiding a young person in their first diy efforts (ie simple-simple)?
Thanks Grindstone for encouraging. I have read Allen's post 2 days ago. But the approach he uses is not by listening, but by calculating the value of inductors and capacitors which I may not want to do. My measured results and simulations can do a better job than a calculator.

I want to select the woofer/ midrange/ tweeter rolloff by listening irrespective of how they measure. For eg. the simulation/ calculator may tell me 0.8mH inductor for low pass, but by listening, I may prefer maybe a 0.35mH inductor as a correct rolloff. I know it won't be easy as it also depends on the music used for designing which itself can vary a lot. I am sure to have some fun this weekend.
 
If primary calculations are done,say volume and size of box using ts parameters, then task is easy. Assemble everything and listen carefully. Then rest can be adjusted according to listening experiments. that is crossover, damping etc.
I remember when l came to listen Kevlar cone speakers in your office, I had suggested that woofer and tweeters are not singing together. Similarly with some other speakers,I couldn't hear good bass and you did remove extra damping. So may be that way you can try.
Thanks Spirovious. I am doing this for my OB speakers itself. Yesterday evening i removed all XO components and connected both my 12" and 8' directly to amplifier. The JBL CD was disconnected. The sound was bright and could not listen for more than 10 minutes. I later connected a 0.35mH inductor in series and listened again. The peaky midrange was tamed a bit. I then connected a 5uF + 0 11mH in a second order configuration capacitor for the CD and listened again. I played Jagjit Singh's Marasim CD to listen. To my ears they sounded ok and balanced. I later changed to ARRehman's - Rehana Tere Dil Me. This sounded very very bright for the same speaker system. Also I played some Jazz numbers which also sounded bright. So something was not correct here making me think that the manual process of tuning is not going to be easy. The major pitfall would be the music chosen for design which can vary a lot.
 
Go for it. The only question that comes to mind is, how would you know and adjust for the limitations of your hearing abilities? I’d imagine each of ours hearing ability is varying, depletes with age and abuse. Is there a risk that you’re designed by the ear speakers might miss on the parts of the spectrum that you don’t keenly listen to? Of course this won’t matter if the speaker is intended exclusively for your own personal listening.

Nevertheless, an interesting experiment.
Thanks Sachin for pointing the listening skew that may ears could have. This exercise is to measure my ears skewness itself. I have done a listening test for various tones with my REW signal generator. The lowest note that I can listen was 35Hz. The highest was 14kHz. That's not bad considering my age and daily abuse.

In my home only I listen to music on my setup. Rest of family members listen on their mobile speakers/ BT speakers / HP.
 
Will be in interesting experiment..while personally I would evaluate subjectively that is with the confidence that all objective measurements have been taken care of by the designer/manufacturer.

The risk if any, and what you would be aware of, is that the system would sound best to you , in your room ,with your components and music..anything else would make it sound very different.

Very curious on your experiment :)
 
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Well I have made a few Bolton sourced speakers about 15 years back! Had to experiment a lot with crossovers ,filling and cabinet design to get optimal sound. Some Bolton speakers with same chassis numbers had different surround material!
In the present day, I opened an old Philips Hq International speaker and found two different woofers: 25748002 IP419 & 25748002 IP 415 ! The cone material and surround appear slightly different. Anyone having any knowledge on difference between IP 415&419. Thanks.
 
If ears and eyes and hands were all that is required to achieve precision, we wouldn't need instruments and tools.
To be fair to the OP, he hasn’t claimed anywhere that subjectively designed speakers would yield superior result than objective testing based design/build. It’s amply clear from his post that he himself sees this as an experiment/desire to carry out.
 
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If ears and eyes and hands were all that is required to achieve precision, we wouldn't need instruments and tools.
If by precision, you mean accuracy, that is an issue that is rarely if ever considered. And, that's because in the world of audio reproduction all that seems to matter is subjective perception. And the problem with that is that there is no objective reference to establish reproduction accuracy. If there were, my opinion is that the majority of equipment in the reproduction chain would be dumped into the trash where it rightfully belongs.
 
Thanks Grindstone for encouraging. I have read Allen's post 2 days ago. But the approach he uses is not by listening, but by calculating the value of inductors and capacitors which I may not want to do. My measured results and simulations can do a better job than a calculator.

I want to select the woofer/ midrange/ tweeter rolloff by listening irrespective of how they measure. For eg. the simulation/ calculator may tell me 0.8mH inductor for low pass, but by listening, I may prefer maybe a 0.35mH inductor as a correct rolloff. I know it won't be easy as it also depends on the music used for designing which itself can vary a lot. I am sure to have some fun this weekend.


I'm thinking that flying completely blind probably isn't going to be as efficient a use of your weekend (or, arguably, useful longer-term) as a weekend deserves :). My sense is that bipolar radiation isn't going to clarify your insights, but muddle them unless your room is almost anechoic.

What I'd do in your position (applaud the inquiry, BTW) is start at the lowest level. Before that, though--a question & comment.

Using the same program material? My suggestion is to keep the program material consistent and short selections. Pick things that elicit the extremes as well, you only really need a handful or fewer of selections. Pick things you sort of like but don't love--because this exercise will destroy your appreciation of things you completely love.

How fiddly it is depends on where you're crossing, as you know. If you're aiming to investigate between about 1.5k and 3.5kHz, you're sunk--leave that spot for last--that spot is crazy-touchy. Humans (some) can ferret-out 1/2 dB changes around there--look at the high-end JBL's that ship to Japan--they have 1/2 dB user adjustments in the "presence region".

Converge from the top and bottom, binary-search. Just like the eye doctor--is it better or worse? "Next." Keep notes.

I assume you have many many hours of ear-time on each driver but suggest you start with one exclusively to get your mental baseline for what each does (and doesn't do!). Listen to anything/everything on each for quite a while. And I wouldn't do it OB, even if that's your ultimate system config. This is about the process and making it efficient. What I'd do is slam-out a big, big test box and make provisions for mounting each AND both drivers. It can be styrofoam or whatever, too--just brace it & fill it up with polyfill or fiberglass or whatever so you're not focused on standing waves--just the drivers. If you have a choice (ie not scrounging existing materials), maybe pick whatever has the biggest Vas and that's your minimum Vb...I'd go 25% larger than that if it's not insane as a first thought. If they're old-old (big Vas), well, you have to fit it in the room so do what you can tolerate. For "extra credit", keep adding blocks/volume eaters until you find the best size for each driver--there will be one. What this gets you is the best the driver can do in that box--it separates those warts/deficiencies and drills the range of capabilities into your ears. Having an enclosure of some sort unloads a bunch of reverberant cues that could have you chasing down blind alleys. Your ears (and brain) already have a bunch of "free-air" knowledge about them--and you know it's not what you want because you're doing this experiment. Maybe you already have "standard" test boxes you can use, being an avid diy'er?

Some things just "don't go together", IMO. Kevlar and aluminum. Paper and plastic, etc. Just examples. The point is, be honest in assessment if you are trying to achieve something that's approximately impossible :)

Think about it like cooking. You are trying to make complementary things. In fact, if I gather correctly, the precise nature of the inquiry regards complementarity. Certain ingredient combinations just don't work. If you can identify those things first, you've saved a lot of time. I know you're hunting rolloffs, but to know desired rolloffs, you have to know the drivers really well by themselves. It may be that those two things just don't go together where you want them to for myriad reasons. Establishing if the objective is reasonably possible early saves you grief and time.

Next, give yourself a chance by doing the calculations. If you want to leave the mic alone, do so. My advice is to teach someone else how you want things measured and have them measure each step and save the files while you stay "blind" in your process. I think you have to calculate to have any chance at succeeding and making sense of it. Absent some structure, the conclusions become matters of chance. Pretend your task is a 2-way and start a fresh design at the ground level.

Do the basics. How far does each stay mostly pistonic? Are they going to be mounted within a quarter wavelength of the XO each other in the end? What are their levels? If not, there's your first problem, etc. If only the mics stay off-limits, sim your brains out from a fresh start like you just helicoptered-in and are seeing it for the first time. Ask yourself--would you even use those 2 drivers together in a 2-way designed to cover your bandwidth target for both, etc.

As always, this is all your call, but that's what I'd do if I were in your shoes. It'd just be so easy to get lost otherwise. I'll accept argument about the transferability to OB, but you might be uniquely qualified to make it after such an exercise. Yes the end-slopes might be different, but that, too, gets you working in a different realm and that has value, IMO. I still think it gets you a tiny bit of structure to investigate the blending--and whether it's even possible to suit your tastes with those parts. I assert that the process of the sims + the listening allows each impression to have a chance at meaning. If you can't hear up high and you're working up-high, enlist a helper. I've used my friends grandkids and they're ruthless :) On matters of a particular instruments timbre/tone, I trust musicians more. FWIW & IMO.
 
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And the problem with that is that there is no objective reference to establish reproduction accuracy. If there were, my opinion is that the majority of equipment in the reproduction chain would be dumped into the trash where it rightfully belongs.
Don’t think so. I doubt say someone liking a darker/warmer reproduction would junk his equipment because it scores low on the newly established objective reference for accuracy. Music listening, except for a very small minority, is mainly about joy, and the determinants of what one enjoys are mostly subjective.
 
Don’t think so. I doubt say someone liking a darker/warmer reproduction would junk his equipment because it scores low on the newly established objective reference for accuracy. Music listening, except for a very small minority, is mainly about joy, and the determinants of what one enjoys are mostly subjective.

There are always going to be people who need someone else to tell them whether or not to enjoy the sound coming out of their system. The weird thing is the amazing need they have to try to convince other people of the same.

Back to the topic:

Hari - my question to you is: with this method, you may find a design with a sound that you like. If so, that's good. However, how do you troubleshoot if the initial prototype doesnt sound good to you? Trial and error? It could work, but it seems quite inefficient unless you set up a very robust/easy-to-tweak test bench for the crossover (I am assuming the cabinet design is a given).
 
The more I think about it, the more convinced I am that this is near impossible to achieve IF the DUT is the only one you are going to be listening to and tweaking. Subjectivity is, well, subjective and is infinitely variable depending on environment et al.
But if you're going to have a reference that you are willing to listen to constantly and if there are constant subjective A/B comparisons made between the reference and the DUT, then yes, it may be achievable. The outcome of this will be educational, informative and very interesting. I suggest that you take this approach first and then in the next round [if there is any] go after your original premise [as I understood it].
 
My two pence :

There are things that SHOULD be measured. Then, there are things that CANNOT be fully measured. Good loudspeaker design is all about doing the measurements first and then going beyond such measurements in a very conscious manner to achieve something special. Fundamental engineering is the bedrock upon which you stand when you wield the magic wand of subjectivity!
 
Thanks to all FMs for the encouraging words for me to try and attempt. I tried one more iteration today playing with different inductors and capacitors. TBH I am no where near to find the right combination for the rolloff. The trial and error method makes the speaker system either very bright or very laid back. I also tried average values but still am not happy with what I am listening. This for me is going to be difficult than I thought. I am running out of inductors now. 2 more days to go before I give up this method. I think I will require more listening analytical skills with this method which I am lacking.
 
Thanks to all FMs for the encouraging words for me to try and attempt. I tried one more iteration today playing with different inductors and capacitors. TBH I am no where near to find the right combination for the rolloff. The trial and error method makes the speaker system either very bright or very laid back. I also tried average values but still am not happy with what I am listening. This for me is going to be difficult than I thought. I am running out of inductors now. 2 more days to go before I give up this method. I think I will require more listening analytical skills with this method which I am lacking.
Sounds very much like JFK
“We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard……”.

Sir please dont take this speech too seriously. It was very easy for JFK to say it but a nightmare for Nasa engineers. Believe you me, a few measuring aids to make your life easier wont hurt and the outcome will be more fulfilling.
 
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