I have to say this is the better color for the baffles. The other two were apealing too but this one just blends the right way... stunning work...
On the tehnical side, some authors here, like Lynn Olson argued that MTM configurations are hard, if not impossible to make them sound right, with WMTMW beeing the hardest. This is due to abnormal lobing and pattern problems. Did you experienced such problems in your other project and do you have any aproach to this? Or you hope just to take advantage of the flexibility of digital crossovers and tune them until seems right?
Good Luck with your project!
On the tehnical side, some authors here, like Lynn Olson argued that MTM configurations are hard, if not impossible to make them sound right, with WMTMW beeing the hardest. This is due to abnormal lobing and pattern problems. Did you experienced such problems in your other project and do you have any aproach to this? Or you hope just to take advantage of the flexibility of digital crossovers and tune them until seems right?
Good Luck with your project!
well if you don't want to continue building speakers, I'm sure you could get a job in advertising, the guys who manage to take the right shot at the right angle to make things look perfect.
Personally, I vote that you keep building speakers for our vicarious pleasure though.
I want......I WANT
Personally, I vote that you keep building speakers for our vicarious pleasure though.
I want......I WANT
Guys I'm taken aback by your comments and thoroughly enjoyed reading them.
Its funny, there were a few times where I could have quit this project or started to cut corners but this forum, the comments and the people made me want something special at the end. Its hard to keep up the motivation with a project like this but one of the things that really helped was taking shots of the little bits progress I'd make and then post them here for others to enjoy and likewise for me to enjoy reading those comments.
I don't think I'll tackle anything on this scale for a year or two but I've learnt tons and, most importantly, I now know chaolin monk like patience.
I think that's the key with these longer term project, expect them to take months or even a year or two.
Its funny, there were a few times where I could have quit this project or started to cut corners but this forum, the comments and the people made me want something special at the end. Its hard to keep up the motivation with a project like this but one of the things that really helped was taking shots of the little bits progress I'd make and then post them here for others to enjoy and likewise for me to enjoy reading those comments.
I don't think I'll tackle anything on this scale for a year or two but I've learnt tons and, most importantly, I now know chaolin monk like patience.
I think that's the key with these longer term project, expect them to take months or even a year or two.
Wingfeather,
we have an audio magazine in Germany that always publishes the step response of tested speakers. It is funny to see what cheap and most expensive speakers have in common: a step response starting with the tweeter, then the midrange driver and then finally the woofer.
You will only find in rare cases speakers which have a step response close to the ideal step response. Create a highpass with a corner frequency of let's say 30 Hz of 2nd order and check the step response of the minphase of this highpass. How many speakers have such a step response, can you tell?
So if you have solutions with passive crossovers and its minphase behaviour you may have a good chance to start a business, selling these crossovers to the speaker manufacturers.
BTW: it is easy to convert minphase filters to linear phase filters with the identical frequency response. So if you can give me a formula describing the amplitude response of a Butterworth or Linkwitz-Riley filter I can easily create such filters for you, either minphase or linearphase. Maybe my formulas are not the right one. Unfortunately I do not have MATLAB and I cannot program it.
Uli
Hi Uli,
Before I begin my reply, I just want to say that it's starting to feel like I'm threadjacking. If shinobiwan or anyone has a problem with these posts about filters and the like then I'll be happy to move to another thread. It is kinda related though! We all just want shin's marvellous speakers to sound their best
Ah, but this is the crucial part! The response should look like that! A system that doesn't have a linear-phase response isn't going to pass such a signal (which contains components at all frequencies) without changing it. Some of the frequency components will be phase-shifted by the filters, and this will change the shape of the wave that comes out.
However.
This is what I was talking about before. This phase-shift is the only change to the signal that the filters make. And since our hearing system can't detect absolute phase, this kind of alteration isn't audible (or is widely believed to be, at any rate. This kind of stuff is such a grey area). I'm afraid I don't have any names of papers to give out, but I know that lots of tests have been done and they all point to this result.
In the end I suppose this one all comes down to one's own principles and philosophy. I think showing someone a graph of the step response of something like a speaker is quite useless because it's impossible to distinguish the truly bad stuff from the benign stuff (like this) just by looking at it. But of course YMMV.
Before I begin my reply, I just want to say that it's starting to feel like I'm threadjacking. If shinobiwan or anyone has a problem with these posts about filters and the like then I'll be happy to move to another thread. It is kinda related though! We all just want shin's marvellous speakers to sound their best
Ah, but this is the crucial part! The response should look like that! A system that doesn't have a linear-phase response isn't going to pass such a signal (which contains components at all frequencies) without changing it. Some of the frequency components will be phase-shifted by the filters, and this will change the shape of the wave that comes out.
However.
This is what I was talking about before. This phase-shift is the only change to the signal that the filters make. And since our hearing system can't detect absolute phase, this kind of alteration isn't audible (or is widely believed to be, at any rate. This kind of stuff is such a grey area). I'm afraid I don't have any names of papers to give out, but I know that lots of tests have been done and they all point to this result.
In the end I suppose this one all comes down to one's own principles and philosophy. I think showing someone a graph of the step response of something like a speaker is quite useless because it's impossible to distinguish the truly bad stuff from the benign stuff (like this) just by looking at it. But of course YMMV.
Wingfeather said:Hi Uli,
Before I begin my reply, I just want to say that it's starting to feel like I'm threadjacking. If shinobiwan or anyone has a problem with these posts about filters and the like then I'll be happy to move to another thread. It is kinda related though! We all just want shin's marvellous speakers to sound their best
Hey Wing
Not at all. I'm enjoying reading it and I've never been one that believes a thread should stay completely on topic. So please continue.
This is probably the most unscientific example you will ever read of but I did some tests of my own implementing min phase LR 4th and 8th order slopes with the proprietary linear phase ones, of equivalent rolloff, contained in the DEQX. No loudspeaker correction, no response shaping, no DRC components but but the DEQX were time aligned.
Noticeable difference. Calmer more realistic and larger soundstage with easily identifiable superiority in imaging.
Theory is cool but I like to experiment and see what sounds better to me. This was an easy conclusion to make from that test.
Let me dig out my old step response for the Perceive 2's that was taken with the DEQX.
Hi Shin,
An interesting result. Can you say more about the filters you were using? Cutoff frequencies? Were these the crossovers between mid/tweeter? mid/woofer? Something else? Did you ever mix and match linear- and minimum-phase?
What I'm doing with my speakers now is linear-phase on the mid/tweet crossover and LR4 on the mid/woofer and woofer/sub.
My reasoning, woolly though I'm happy to admit that it is, is that the linear-phase top crossover will help to preserve the waveshape of much of the HF transient-type sounds. As I've said, I'm not sure how important this is from a theoretical standpoint but I feel that if there are psychoacoustic problems with not maintaining waveshape then they'll probably be focussed towards the HF end of things. A combination of hearsay and intuition, really - and I know these are terrible reasons for justifying an engineering decision. The other crossovers are minimum-phase because the room will be playing a much bigger part at 200Hz (where the mid/woofer crossover is) and below - and any attempt at maintaining phase here will only be ruined acoustically.
The nice thing with using an FIR for this top crossover though is that it can be very short and do its job well. I'm using around 200 taps right now, which is easy on the CPU and produces only around 1ms of time-domain ripple. So there aren't really any drawbacks to using it. Using FIR filters for the lower crossovers would be more problematic, with raw required computational power becoming an issue because the filters have to be much longer. I think the benefits of using them down there are much more questionable.
Does this view (linear phase being more important at HF) correlate with what you observed in your tests at all?
An interesting result. Can you say more about the filters you were using? Cutoff frequencies? Were these the crossovers between mid/tweeter? mid/woofer? Something else? Did you ever mix and match linear- and minimum-phase?
What I'm doing with my speakers now is linear-phase on the mid/tweet crossover and LR4 on the mid/woofer and woofer/sub.
My reasoning, woolly though I'm happy to admit that it is, is that the linear-phase top crossover will help to preserve the waveshape of much of the HF transient-type sounds. As I've said, I'm not sure how important this is from a theoretical standpoint but I feel that if there are psychoacoustic problems with not maintaining waveshape then they'll probably be focussed towards the HF end of things. A combination of hearsay and intuition, really - and I know these are terrible reasons for justifying an engineering decision. The other crossovers are minimum-phase because the room will be playing a much bigger part at 200Hz (where the mid/woofer crossover is) and below - and any attempt at maintaining phase here will only be ruined acoustically.
The nice thing with using an FIR for this top crossover though is that it can be very short and do its job well. I'm using around 200 taps right now, which is easy on the CPU and produces only around 1ms of time-domain ripple. So there aren't really any drawbacks to using it. Using FIR filters for the lower crossovers would be more problematic, with raw required computational power becoming an issue because the filters have to be much longer. I think the benefits of using them down there are much more questionable.
Does this view (linear phase being more important at HF) correlate with what you observed in your tests at all?
I too love the changes in direction that this thread takes, and I learn a lot from it.
Or would like too , sometimes it's a bit over my head. I too have a deqx so am following this with interest, but my knowledge needs to be upped a bit.
Is there a quick, well explained primer that I could be pointed to that will help fill in the blanks of these posts of the more knowledgable? eg linear phase minimum phase etc. Maybe trawling through wikipedia might be the best bet, but there could be a specifically written article for all I know....
I remember your earlier posts too Wingfeather, was it really this thread and how long ago was it! Doesn't time fly ha ha.
I for one am glad that you didn't cut corners Shinobiwan, and I think that even you realise that no matter how tempting at the time it might have felt a 'perfectionist' like you would have forever regretted it.
Pity I'm in Australia, as I would have been the first to put in 'first dibs' on them when you start the next project. Which you will. You can't help yourself can you!
And from what I've seen previously you seem to let your masterpieces go for a song!! with each new project. The weather in England is enough to keep me away (and the fact that the pommie teams are no good at sport) but living there for the off chance of grabbing one of your creations.............hmmm.
Or would like too
, sometimes it's a bit over my head. I too have a deqx so am following this with interest, but my knowledge needs to be upped a bit.Is there a quick, well explained primer that I could be pointed to that will help fill in the blanks of these posts of the more knowledgable? eg linear phase minimum phase etc. Maybe trawling through wikipedia might be the best bet, but there could be a specifically written article for all I know....
I remember your earlier posts too Wingfeather, was it really this thread and how long ago was it! Doesn't time fly ha ha.
I for one am glad that you didn't cut corners Shinobiwan, and I think that even you realise that no matter how tempting at the time it might have felt a 'perfectionist' like you would have forever regretted it.
Pity I'm in Australia, as I would have been the first to put in 'first dibs' on them when you start the next project. Which you will. You can't help yourself can you!
And from what I've seen previously you seem to let your masterpieces go for a song!! with each new project. The weather in England is enough to keep me away (and the fact that the pommie teams are no good at sport) but living there for the off chance of grabbing one of your creations.............hmmm.
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