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- Tom_S 2:52AM
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Learning oppurtunities...
So I like to think I always learn something as I go, with each project. As an example, the recently completed DSA175 project. While the woofer is not the best sounding driver - it is an obvious improvement from the paper cone version. The specific learning moment was noting the reduction in distortion due to the metal cone, the shorting ring, or both.
The impedance curve does not indicate the presence of a shorting ring - but there are other ways of lowering distortion and I suspect the shorting ring was doing its job regardless of noticing it on the impedance sweep. I also feel the aluminum cone contributes to the reduction in distortion between the paper and aluminum cone versions. I consider it a learning moment because we are generally conditioned to correlate the shape of the impedance curve with an expected distortion profile and this is not always the case.
So what say you? What have you recently learned or realized or had affirmed?
The impedance curve does not indicate the presence of a shorting ring - but there are other ways of lowering distortion and I suspect the shorting ring was doing its job regardless of noticing it on the impedance sweep. I also feel the aluminum cone contributes to the reduction in distortion between the paper and aluminum cone versions. I consider it a learning moment because we are generally conditioned to correlate the shape of the impedance curve with an expected distortion profile and this is not always the case.
So what say you? What have you recently learned or realized or had affirmed?
I have a signature.
Comments
The shape and anomlies in the Z curve are far more important, as or the rest of the measurements once in cab.
I often hear that sibilance is caused by the woofer breakup not being pushed down enough. I agree, but on a recent project I couldn't get the S sound to go away. I finally traced it to the ND28F tweeter. I was asking the tweeter to play a lower than 2K.
So my learning or reaffirmation was to remember to listen to the drivers individually if possible.
I had learned that earlier with the Mini PT planer tweeter, but some how discounted that learning with a 28 mm dome tweeter.
Second build a few years later, I bought measuring equipment and did 4-5 different versions of the enclosure, finally settled on a fully active setup with MiniDSP. That was the deadhorse. Great drivers, "meh" sound with lots of boxes left unticked in the fully active department.
Next build was the Leviathans, I learned a lot about building large enclosures and finishing in this build. I forgot to use filler on the subwoofer box butt joints, and it's night and day between the two. These were also fully active - what a huge waste of money on cables, DSP and Amps. Sounded "good" and flat to 13Hz, but not exactly a flawless design.
Next was the Harbingers, did some "precision" work with real wood in this build, as well as my first passive crossover speaker, marked improvement on measurements, construction, damping, etc. on this build. Great sound, great off-axis FR, too. The finish was intentionally flawed and looked great. FWIW I really prefer passive crossover speakers.
WIP is the Shockwaves doing a 3-way with a coaxial driver and a passive radiator as well. These will have passive crossovers and be nearly full-range for music. Also, they have a constrained layer panel enclosure. I'm wanting to make some distortion measurements on these and I want them to have great off-axis performance like the Harbingers did.
Next build isn't really planned, but if the coaxial thing works, I want to build another 3-way coaxial with a veneered, constrained layer, passive crossover, <35Hz F3, and great off axis FR. Maybe even powered with diy amps? With every build I try to focus on learning a new aspect of the hobby.
Taught me a valuable lesson about the oft-repeated "modeling shows a similar F3, you will be alright" mantra. Something has to give when two drivers with wildly varying T/S parameters model with a similar F3.
I am willing to accept 1/2db difference in sensitivity - but 1-1/2db is pretty excessive for unit to unit.
That being said, other than those AC units, it has been awhile since I have come across any other drivers with outright bullshit advertised specifications. In fact, I am consistently surprised at the level of QC in even cheap drivers these days.
I heard a while back (may have been from you) that AC drivers were paticularly bad. Scary at the beads and trinkets traded for them.
I am also thinking of doing a dream build with all MCM drivers because I suspect the new KB will be good enough to qualify as high end.
I try to learn something new with each build. Whether it's in the drivers, crossover, cabinets, etc. I've learned to expect consistency with Dayton woofs, but not necessarily great sound.
I've learned or tried to at least improve on taking criticism (constructive and otherwise). That helped me enjoy this hobby again.
Seems hard to give constructive criticism via the internet. Few people assume positive intent.
I'm guilty as well assuming people are not being helpful. Seems like the new criticism is ignoring.
Sugguestions are great, and I have learned a lot from MANY, even from "noobs" who see things with fresh eyes, but to tell someone they are wrong when they are simply different can be the cause of many issues.
The science is the science. Period. How we apply and use it....Well, that's the rub.
"If it were me, I would have tanked the breakup and tuned it lower"
"Not tanking the breakup and tuning it so high is a mistake"
"In some cases, otherwise unexplained hiss and/or overall impression of brightness can be attributed to untamed breakups or not tuning deep enough"
All three are different ways of telling someone they may have made a mistake - all three are well intentioned but almost impossible to receive easily due to some massive assumptions made on the part of the critic.
Perhaps a better way is to lead off with "How did the overall tonal balance sound relative to some other speakers you have listened to?" - and pursue it further if the designer says something like "Kind of bright - but the tweeter level measures pretty much in line with the mid".
I no longer really listen to that type of feedback, and I rarely offer that type of feedback any more unless directly asked to do so by someone. There is nothing to be gained by publicly proclaiming someones design to be a piece of shit - in DIY that is. I figure commercial guys are open game, for the same reason McDonald's is open game and movie studios are open game and pop singers are open game.
The above being said, the type of feedback that drives me up a wall is... "Crossover needs better integration" or "Can't quite put my finger on it, but it seems like the bass is slow" or "I feel like there are some notes rounded off in the 3kHz region" or other such nonsense. Absent knowledge of said crossover and expanding on the particular issue and offering specific advice intended to correct any perceived issues - that advice is absolutely meaningless, and does nothing but make the critic sound a bit pompous.
Ultimately, I guess I am fairly jaded these days in that I suspect a lot of people with very public opinions on audio in general just have an urge to beat people up. When I make comments like "Led Zeppelin" is over-rated, I receive a lot of shit from people who, you would think based on their comments, must believe I personally consider people who like Led Zeppelin (which I do - they are just over rated) to be pieces of shit. Like - if I said Justin Bieber is a piece of shit, I would get high-fives and hell yeahs from the crowd. Never let people tell you the hive mind does not exist in all areas of life.
So I guess what I have learned over the years is that telling someone their god isn't real is or their taste is inferior is just asshole behavior. There are ways to lead into constructive criticism, and the one-way blind nature of the internet, unfortunately, makes it difficult to convey criticism without coming across an ass.
TL;DR telling someone their speaker should be shit because of something they did you disagree with or telling someone their speaker is shit without offering advice and support makes you an asshole, whether intentional or not.
I tried multiple ways, with multiple speakers and headphones, and couldn't hear a difference on any of them. The only way I was able to finally tell the difference was to run them through the Liberty Audio DiffMaker program.
It was proven to me then that this whole obsession about "linear phase" or amount of phase rotation at the crossover point just is not audible--to me, anyway. And don't get me wrong, it's not that I'm going to go out there and slap 1st order crossovers out of people's hands... if achieving perfect time alignment and linear phase is an exciting design goal for you, have at it. But it was a relief for me that I didn't have to worry so much about it, or time aligning drivers to achieve perfect phase coherence was going to make an audible difference in the final product.
Again, I REALLY wish I could find that thread. If anyone has it, or can find it, PLEASE SHARE.