I think you can be even a bit more specific.
Examples of key constraints are like; total budget, size, maxSPL, freq range, other context like room size, acoustic stuff, overall design goals.
A few of those can be even divided in further details. Like passive or active filter and certain preferences in case some of the constraints have to be compromised.
A good example of this is something like: rather having a lower frequency range instead of maxSPL (because absolute listening levels are limited anyway).
All of this looks daunting at first, but you will very quickly see that it actually makes the project a whole lot easier.
Or you can just start building for the fun of it! Which is also great obviously
Can't change the project specifications after the contract is let.
Expect HUGE CHANGE ORDERS.
Thanks DT
I installed the mid/tweeter cabinets into my main system. This requires I remove the existing cabinets (Satori textreme) from the stand and mount the new ones. They are secure with a 5/16 inch bolt through the bottom of the speaker. The electrical connection is to a screw-terminal bus in the upper part of the stand, and the driver wires are fitted with ring terminals. The bottom part of the stand contains the Hypex FA253 amp.
I made near field and polar response measurements of the completed system. The differences between these measurements and the polar responses of the waveguide and midrange box individually (post # ) are insignificant… i.e. there were no surprises. There were some small diffraction differences in the mid response now that the tweeter waveguide is mounted above it and it is on the amp stand rather than the test stand, but these were minor. My simulations from this point forward will use the latest measurements.
I am going through test and evaluation (T&E) of the finished speaker. The current DSP filter is one that makes T&E more simple and easy, it is a flat on-axis response with idealized LR4 crossover slopes at 1.6k, and LR2 at 200 Hz. It is not necessarily the best possible filter from a DI perspective or a PIR perspective. Nonetheless, this system sounds really good. Right from the start I noticed very precise image location, and a great perception of depth. I will have more to say later as the DSP filters become more refined.
j.
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I made near field and polar response measurements of the completed system. The differences between these measurements and the polar responses of the waveguide and midrange box individually (post # ) are insignificant… i.e. there were no surprises. There were some small diffraction differences in the mid response now that the tweeter waveguide is mounted above it and it is on the amp stand rather than the test stand, but these were minor. My simulations from this point forward will use the latest measurements.
I am going through test and evaluation (T&E) of the finished speaker. The current DSP filter is one that makes T&E more simple and easy, it is a flat on-axis response with idealized LR4 crossover slopes at 1.6k, and LR2 at 200 Hz. It is not necessarily the best possible filter from a DI perspective or a PIR perspective. Nonetheless, this system sounds really good. Right from the start I noticed very precise image location, and a great perception of depth. I will have more to say later as the DSP filters become more refined.
j.
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For development work I installed a DSP filter which is flat on-axis and has very close phase alignment between the mid and the tweeter. This allows me to set the gain levels and tweeter delay with no ambiguity and a low probability of error. However, this filter is not optimized for the best DI or PIR response. I view it as the starting point for fine tuning the performance, both objectively and subjectively.
I have not yet taken the whole system outside for low frequency ground plane measurements… therefore, my woofer gain settings are not finalized. I made 10 in-room measurements in the 100 – 300 Hz range for the mid, the woofer, and both together. I took measurements of the raw driver responses, and the fully eq’d responses. Based on all of this data, I estimated the relative output of the woofer relative to the mid, and then used this to set the gain.
I am very pleased with the performance. They have a smooth natural sound, great image specificity, excellent presentation of depth. Excellent detail.
The next step is to try some new DSP filters I have developed which are more optimized for DI and PIR performance.
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j.
I have not yet taken the whole system outside for low frequency ground plane measurements… therefore, my woofer gain settings are not finalized. I made 10 in-room measurements in the 100 – 300 Hz range for the mid, the woofer, and both together. I took measurements of the raw driver responses, and the fully eq’d responses. Based on all of this data, I estimated the relative output of the woofer relative to the mid, and then used this to set the gain.
I am very pleased with the performance. They have a smooth natural sound, great image specificity, excellent presentation of depth. Excellent detail.
The next step is to try some new DSP filters I have developed which are more optimized for DI and PIR performance.
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j.
Hello @hifijim, Question?
I have the feel of the coverage angle of the Purifi mid-woofer and the coverage angle of the tweeter. The 24dB slope of the 1.6kHz crossover is also known
The distance between the centers of the mid and tweeter looks to be 12 inches plus +/- some.
Your measurements show some degree of interaction and lobing at the 1.6kHz crossover frequency.
What do your ears tell you? Between sitting and standing is there a large or noticeable difference because of the narrowing vertical coverage at the 1.6kHz crossover Frequency?
Thanks DT
I have the feel of the coverage angle of the Purifi mid-woofer and the coverage angle of the tweeter. The 24dB slope of the 1.6kHz crossover is also known
The distance between the centers of the mid and tweeter looks to be 12 inches plus +/- some.
Your measurements show some degree of interaction and lobing at the 1.6kHz crossover frequency.
What do your ears tell you? Between sitting and standing is there a large or noticeable difference because of the narrowing vertical coverage at the 1.6kHz crossover Frequency?
Thanks DT
Yes, my CTC distance between mid and tweeter is 280 mm (11”). The design axis for simulation and measurement is exactly halfway between the two, so in simulation the tweeter is at y = + 140 mm and the mid is at y = -140 mm.
My actual seated listening height is below the design axis, it is more or less even with the center of the mid. This means I listen at a -3.5 degree angle, but this slight angle has no consequence in either simulation or measurement compared to on-axis.
When standing or walking around, I am a bit further away from the speakers. At this distance, my ears are at + 10 degree, and according to simulations I have a -2 dB suckout from 1.2k to 2.4k. I can hear a mild change in tonality at this position, but it is not annoying or distracting, it is just different. It is fine for casual listening. All of my serious listening is done while seated in the sweet spot.
My actual seated listening height is below the design axis, it is more or less even with the center of the mid. This means I listen at a -3.5 degree angle, but this slight angle has no consequence in either simulation or measurement compared to on-axis.
When standing or walking around, I am a bit further away from the speakers. At this distance, my ears are at + 10 degree, and according to simulations I have a -2 dB suckout from 1.2k to 2.4k. I can hear a mild change in tonality at this position, but it is not annoying or distracting, it is just different. It is fine for casual listening. All of my serious listening is done while seated in the sweet spot.
Hello hifijim, Another Question?
You have spent a lot time and effort designing, building and measuring your speakers.
Your Santori TW29BN WG plus Purifi mid-range have turned out just as planed.
Your Txtream also turned out just as planed.
By the nature of the physical dimensions the CTC between the tweeters and mid-range drivers is a fair amount different between between the designs.
For standing, sitting, walking around or critical listening does the difference in CTC distance make a meaningful difference to your listening impressions?
Thanks DT
You have spent a lot time and effort designing, building and measuring your speakers.
Your Santori TW29BN WG plus Purifi mid-range have turned out just as planed.
Your Txtream also turned out just as planed.
By the nature of the physical dimensions the CTC between the tweeters and mid-range drivers is a fair amount different between between the designs.
For standing, sitting, walking around or critical listening does the difference in CTC distance make a meaningful difference to your listening impressions?
Thanks DT
I am just at the point where I am satisfied with the voicing of this system. So now I am ready to do a direct comparison between the TXT system and the Purifi-WG system. It has been about 3 weeks since I have listened to the TXT system, so I am hesitant to discuss my impressions at this point in detail, but I feel comfortable making some general statements....
There are differences in how the two systems present an image, the way they create the illusion of 3 D space. I will get more into that in a future post.
If a speaker sounds quite different while standing than while sitting, the primary cause is likely to be a peak or null in the + 15 to + 20 degree vertical direction... a peak would be more intrusive, but a very deep null would also be noticeable. This kind of problem at +15 to + 20 degrees vertical has little to do with CTC spacing, and a lot to do with crossover slopes and good simulations.
jim.
It makes a lot less difference than you might think. My impressions so far is that the Purifi-WG system sounds quite similar to the TXT system. Tonality and frequency balance are almost the same, which is my intent. With DSP and good measurements, it is possible to control frequency response to a fine degree, and so it is understandable that I would end up with a voicing on the two systems that is so similar.
There are differences in how the two systems present an image, the way they create the illusion of 3 D space. I will get more into that in a future post.
If a speaker sounds quite different while standing than while sitting, the primary cause is likely to be a peak or null in the + 15 to + 20 degree vertical direction... a peak would be more intrusive, but a very deep null would also be noticeable. This kind of problem at +15 to + 20 degrees vertical has little to do with CTC spacing, and a lot to do with crossover slopes and good simulations.
jim.
hjfijim,
Thanks Jim.
You are right on target when you are speaking of peaks, nulls and crossover slopes.
To my way of thinking there are tradeoffs between using waveguides and minimizing center-to-center measurement.
For near-field or near direct listening with the speakers on my desk or bench, tuning the coverage angle and room reflections is much less important than listening upstairs in the home theater.
I am using 6-1/2" Purifi mid-woofers and Satori flat face TW29BN-B tweeters. (with a woofer tucked in under the table top.) I do not notice if I swap in a WG tweeter or not. Room reflections seem to play a much smaller part if I sit up close to the speakers at the bench.
What makes a large difference is reduced distortion at higher output levels. The Purifi mid-woofer is a keeper.
Thanks DT
For the past several weeks I have been listening to two filters. The baseline is a straightforward 200 Hz LR2 + 1.6k LR4. The on-axis response slopes down by about -2dB from 100 Hz to 10k. In the 1.6k crossover region, I have very good phase alignment between the mid and tweeter.
The second one has been optimized for the smoothest possible DI and PIR response. To achieve this, I had to reduce directivity from 1k-2k by about 2 dB. This required a bit of a funky filter. The crossover frequency is now 1.3k. There is a 60 degree phase difference between the mid and tweeter, and some aggressive EQ to bring it all back to flat. The DI now rises smoothly from 300 Hz to 10k. The PIR curve is a straight line from 100 to 10k sloped down at -1.2 dB/octave.
In theory, this second filter should be superior to the baseline from the standpoint of tonality and balance because it has a smoother power response and PIR response. According to conventional wisdom, the baseline (first) filter should have an advantage in creating a 3D sense of space and imaging because it has better phase alignment through the crossover region.
In reality, I cannot really tell them apart. The performance of the system with either filter is very high. Clarity, detail, tonal balance; they are equal. Imaging, localization, 3D sense of space; they are equal. Dynamics, and a sense of naturalness; they are equal. My going in assumption was that I would hear a difference, and I am a bit surprised that I did not. A bit disappointed also… I was hoping to draw some conclusions regarding certain perceived sonic attributes and physical measurements.
So that is what I have so far.
j.
The second one has been optimized for the smoothest possible DI and PIR response. To achieve this, I had to reduce directivity from 1k-2k by about 2 dB. This required a bit of a funky filter. The crossover frequency is now 1.3k. There is a 60 degree phase difference between the mid and tweeter, and some aggressive EQ to bring it all back to flat. The DI now rises smoothly from 300 Hz to 10k. The PIR curve is a straight line from 100 to 10k sloped down at -1.2 dB/octave.
In theory, this second filter should be superior to the baseline from the standpoint of tonality and balance because it has a smoother power response and PIR response. According to conventional wisdom, the baseline (first) filter should have an advantage in creating a 3D sense of space and imaging because it has better phase alignment through the crossover region.
In reality, I cannot really tell them apart. The performance of the system with either filter is very high. Clarity, detail, tonal balance; they are equal. Imaging, localization, 3D sense of space; they are equal. Dynamics, and a sense of naturalness; they are equal. My going in assumption was that I would hear a difference, and I am a bit surprised that I did not. A bit disappointed also… I was hoping to draw some conclusions regarding certain perceived sonic attributes and physical measurements.
So that is what I have so far.
j.
nice test!
One day I was adjusting single mono speaker tweeter delay for fun to hear what it does to perceived audio quality. DSP is located accross the room and was sitting beside it jogging the adjustment wheel, changing the delay. To my surprise there was no audible difference until the delay was multiple milliseconds so that the sources separated.
Having red some Griesinger papers I believe phase information is so scrambled at the distance due to room reflections brain just can't make a difference, localization gone and so on. According to his studies hearing system attaches attention to harmonics of sounds, and when phase is a mess / room messing it up the harmonics turn into noise and hearing system does not lock in, no engagement.
Listening too far is the typical hazy sound all along, brain lost the phase information already so it doesn't matter if I scramble it some more with DSP. Haven't redone the test at close distance yet but plan to. If there is audible difference it must be at close distance where room hasn't already ruined it, very close.
Whats interesting he seems to suggest that its either or, either the harmonics are heard and brain locks in or not. And my own experiment on my setup suggests so too, literally one step further from the speakers and the good sound is gone, one step closer and sound is fine, quite a sharp difference in perceived sound. Reasoning from this, phase needs to be fine enough for this to happen. But also, listening distance must be close enough or there is no difference. You need to lock into harmonics
One day I was adjusting single mono speaker tweeter delay for fun to hear what it does to perceived audio quality. DSP is located accross the room and was sitting beside it jogging the adjustment wheel, changing the delay. To my surprise there was no audible difference until the delay was multiple milliseconds so that the sources separated.
Having red some Griesinger papers I believe phase information is so scrambled at the distance due to room reflections brain just can't make a difference, localization gone and so on. According to his studies hearing system attaches attention to harmonics of sounds, and when phase is a mess / room messing it up the harmonics turn into noise and hearing system does not lock in, no engagement.
Listening too far is the typical hazy sound all along, brain lost the phase information already so it doesn't matter if I scramble it some more with DSP. Haven't redone the test at close distance yet but plan to. If there is audible difference it must be at close distance where room hasn't already ruined it, very close.
Whats interesting he seems to suggest that its either or, either the harmonics are heard and brain locks in or not. And my own experiment on my setup suggests so too, literally one step further from the speakers and the good sound is gone, one step closer and sound is fine, quite a sharp difference in perceived sound. Reasoning from this, phase needs to be fine enough for this to happen. But also, listening distance must be close enough or there is no difference. You need to lock into harmonics
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What I failed to write that if its truly like Griesinger papers indicate, black and white kind of audible effect with phase, then one must know which side one is listening in order to be able to evaluate things. One must know where the transition happens in their room with their setup, or have experience to distinguish the sound. Now, if you listen at the poor side phase stuff on the speaker wouldn't matter, or if listening inside perhaps it doesn't matter there either other than moves the transition closer or further from the speaker, black and white effect. If there is more to it, subtle differences, then I think one should definitely be sure to listen close enough, within the zone.
In other words it would be crucial to hear the effect in order to be able to identify it. The one step transition between good and bad sound. I'm not sure if this is audible for all in all rooms, I'm lucky to have it and play with it, but don't know what in my system makes it so clear Anyway, I think I now have powerful tool to reason and listen and think about and recommend anyone interested to find it in their systems as well.
In other words it would be crucial to hear the effect in order to be able to identify it. The one step transition between good and bad sound. I'm not sure if this is audible for all in all rooms, I'm lucky to have it and play with it, but don't know what in my system makes it so clear
Anyway, I think I now have powerful tool to reason and listen and think about and recommend anyone interested to find it in their systems as well.
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While i tend to agree, my view at this moment is that a speaker needs to produce the sound with flat response and no time variations in its bandwidth. Then it produce the sound as captured in the recording at that point in a space.( I neglect for a moment any modifications during mixing/mastering.)
Then the sound will be influenced by the room , but that is also true in the space (musical hall) were the music was recorded(if the soundstage is included in the recording).
Note that a lot of music albums contains (partially or fully) synthesized soundstages, therefore all bets are off then in my view.
Still even then the separation of the sound are important for me.
Then the sound will be influenced by the room , but that is also true in the space (musical hall) were the music was recorded(if the soundstage is included in the recording).
Note that a lot of music albums contains (partially or fully) synthesized soundstages, therefore all bets are off then in my view.
Still even then the separation of the sound are important for me.
"Then the sound will be influenced by the room , but that is also true in the space (musical hall) were the music was recorded(if the soundstage is included in the recording)."
Okay, but if we listening in a typical reflective room, we don't hear just the effect of the room where the recording happened but also the effect of the room in which we are listening. The soundstage of approx. 99,9% of the recordings is made up (in the process of mixing, mastering etc.), so it's not the real acoustics of the recording event. Of course this is created in a reflective room (in the studio), but if we want to hear what they heard in the studio, we need the electronics, speakers, room acoustics etc. of the studio.
And if we want to hear the real acoustics of a recording event (at least as far as it is possible to record), then we need a recording that is not processed in any way after it recorded and we need perfect electronics, perfect speakers and an anechoic place/room where we can listen to it.
Okay, but if we listening in a typical reflective room, we don't hear just the effect of the room where the recording happened but also the effect of the room in which we are listening. The soundstage of approx. 99,9% of the recordings is made up (in the process of mixing, mastering etc.), so it's not the real acoustics of the recording event. Of course this is created in a reflective room (in the studio), but if we want to hear what they heard in the studio, we need the electronics, speakers, room acoustics etc. of the studio.
And if we want to hear the real acoustics of a recording event (at least as far as it is possible to record), then we need a recording that is not processed in any way after it recorded and we need perfect electronics, perfect speakers and an anechoic place/room where we can listen to it.
Oh yes, that is reasonable, playback system should not give or take away whats in the recording.
But, as the sound leaves the speaker its now in a room and perceived by hearing system. According to Griesinger's work phase information is easily lost in the room, hearing system is not able to properly attach attention if phase information gets on the playback process, harmonics on instruments on the record gets mixed into noise. Which I think could happen on the recording occasion already.
What we can do at the playback stage is to listen close enough so that the direct sound is strong enough compared to sound (noise) in the room so that brain can properly resolve whats on the recording, get engaged to sounds on the record. Besides the room and slitening distance, the playback system needs to retain the information in sufficiently high level as you say, but the ultimate boss that can make or break it before hearing system is the room. I think it doesn't matter if you have best possible unobtanium million dollar system if you listen it from too far away. Griesinger work is on live music, even real sources lose it, due to room.
Griesinger studies are mostly on live sound, but are the same for playback systems as well. On his another paper "The physics of auditory proximity and its effects on intelligibility and recall" there is something that it is not possible to hear his Proximity if sound is played back by two separate sources, which is basically stereo phantom center. Interesting stuff.
To me all this seems quite plausible, and reasonable in a way since I have this similar experience on my own listening room and situation. I can hear the effect, its quite dramatic shift. As explained on earlier post I was not able to hear subtle effects on phase (mismatch of multiway speaker) at distance other than distinct delay after great mismatch. I'm sure this is currently the only perceived effect of phase that I've been able to recognize myself. From this I can simplify for now that its pretty much the only effect that phase has on perception in loudspeaker context with reasonably well done loudspeaker. There is probably more, I just don't know it.
It would be very interesting to know what others perceive about phase, do you have this critical distance with your listening setup? According to Griesingers work and trying to fit my experience to it I think everyone should have the phenomenon available at their home stereo systems. The next question would be, after you have perceived it, do you really hear additional difference with phase and in which circumstance, close or far listening? Or both? Different effects on both? To me Griesinger work suggests there should not be too much difference, hearing locks in, or doesn't, the rest is about amplitude response, envelopment and all that stuff. This would nicely fit to all kinds of debate with audio systems, some people prefer something else than others, and it might all be due to the person listening either close enough or too far away.
If you read Griesinger stuff on it, what happens the ear is very sensitive to amplitude, frequency response. All that the phase mismatch does is it scrambles harmonics so that amplitude drops, and so on, hearing system doesn't get caught and the sound localization and timbre suffers.
ps. although I write its night and day difference I'm not sure about it how other people consider it, or recognize it. I mean I have really good sound in general everywhere on the living room but the last bit of stereo clarity, envelopment and all that stuff happens only when small enough listening triangle. I can imagine that if I've never heard the good sound I would perhaps think making wider coverage speakers to widen the "stereo image" as its quite flat and narrow between speakers listened too far since there is not much early side reflections. But, I consider the close sound so much better, all the width and depth and everything is there so in fact I need even narrower coverage speakers to extend it all the way to listening spot, counter intuitive but Griesingers work suggests so, and it feels very reasonable having heard it, experimented with the system.
This explains to me a lot of things, for example why would some people prefer something else than others, it all depends what they have running in their system with the room and do they recognize themselves having the Griesinger's proximity, or coherence, or what you wanna call it, engagement. Different amps, distortion, directivity, even edge diffraction, all the stuff is connected to how harmonics come through, perhaps enhanced or scrambled, and if you listen close or far. But, since I haven't shared the audio experience with others I'm not sure if this is just my poor system fault, am I imagining the stuff, or is this something that is clear to anyone else but me and so on
so, thanks for your post, but what I'd like to read is someone getting the phenomenon heard with their setup, the transition.
Point of the experiment is is to have system setup so that you can step in and out good sound, so that you can learn how each of them sounds, get the audible phenomenon familiar to you.
Here is how I found it: put speakers some distance apart, say 2m, perhaps third of width of the room. Now, start listening tip of equilateral listening triangle, then move forward along the center normal between speakers, perhaps all the way up to between the speakers, perhaps back off as far as you can. In general move along the center normal maintaining equal distance from your head to both speakers and try to hear when the transition happens. Try to get the perceived effect, distinct change with quite short distance, what Griesinger talks about. Play with toe-ins if you wish, shorten distance between the speakers, or widen up, experiment away focusing on listening, you need to get the transition between the two states, when brain can get engaged to the phantom center, and when its not.
Here is what to listen to: On the transition you should notice clarity of the phantom center changes, its more clear when you are close enough, and perhaps little blurry when too far out. Other quite easily noticed effect in my setup is envelopment, when close enough sound seems more enveloping while too far out sound is more in front of you, between the speakers. In general its difference between 3D and 2D kinda thing, being inside the sound, or in front off.
Listen to spoken word or white noise that is mixed dead on center for solid phantom image. Put same signal to both speakers to be sure. We are listening the phantom center at first. Phantom center should localize between speakers always, listening close or far, if not I think you cannot hear it anyway due to speakers being mismatch and phases scrambled. My speakers don't have any sound localize to them done like this, phantom center is dead center and speakers seem mute. When you think you've got something try any music you fancy. Try to zone in on it how ever you wish. Its very repeatable after you learn /be able to hear it.
For reference I have quite high DI system, cardioidish response from 200Hz up, ~90deg nominal waveguide on tweeter. I have quite normal living room without any acoustic treatment, just normal furnishing with few sofas and so on, telly between the speakers. Its perhaps 6x8m room or something like that, 2.5m ceiling. Maximum listening distance, where the transition happens is about 2.2 meters from speakers, so about 2.2m stereo triangle is max I can have in the room for good sound. I would assume distance might be shorter if:
If still no perceived effect? my system / posts might be a crap shoot but I have some faith in Griesingers work and since it seems to happen in my place it ought to happen in your place too
Like anything written its hard to relate the message to anything meaningful if there is no auditory experience. This is something everyone needs to experiment themselves, with their own systems, to get the audio perception, to hear the one step transition to be able to recognize what good enough phase / harmonics sounds. I think this is one of the most important things for DIY loudspeaker folks to get experience on, something that gives perspective on anything else, anchor for relative importance of things. Have noisy unbraced bass box with leaking port? So long clarity. Have too much excursion and resulting IMD with the mid driver? Good bye recorded harmonics, and so on This would be very great thing, think about it, the system needs to be good to have the clear sound at listening distance you wish with playback level you wish, quite clear target to strive for, common denominator that connects 99% of texts been written on the forum
Ah well, sorry spamming about it I'm just trying to get response from all of you what you think, encourage to test it and then write about it so I could relate my experience better.
Here is how I found it: put speakers some distance apart, say 2m, perhaps third of width of the room. Now, start listening tip of equilateral listening triangle, then move forward along the center normal between speakers, perhaps all the way up to between the speakers, perhaps back off as far as you can. In general move along the center normal maintaining equal distance from your head to both speakers and try to hear when the transition happens. Try to get the perceived effect, distinct change with quite short distance, what Griesinger talks about. Play with toe-ins if you wish, shorten distance between the speakers, or widen up, experiment away focusing on listening, you need to get the transition between the two states, when brain can get engaged to the phantom center, and when its not.
Here is what to listen to: On the transition you should notice clarity of the phantom center changes, its more clear when you are close enough, and perhaps little blurry when too far out. Other quite easily noticed effect in my setup is envelopment, when close enough sound seems more enveloping while too far out sound is more in front of you, between the speakers. In general its difference between 3D and 2D kinda thing, being inside the sound, or in front off.
Listen to spoken word or white noise that is mixed dead on center for solid phantom image. Put same signal to both speakers to be sure. We are listening the phantom center at first. Phantom center should localize between speakers always, listening close or far, if not I think you cannot hear it anyway due to speakers being mismatch and phases scrambled. My speakers don't have any sound localize to them done like this, phantom center is dead center and speakers seem mute. When you think you've got something try any music you fancy. Try to zone in on it how ever you wish. Its very repeatable after you learn /be able to hear it.
For reference I have quite high DI system, cardioidish response from 200Hz up, ~90deg nominal waveguide on tweeter. I have quite normal living room without any acoustic treatment, just normal furnishing with few sofas and so on, telly between the speakers. Its perhaps 6x8m room or something like that, 2.5m ceiling. Maximum listening distance, where the transition happens is about 2.2 meters from speakers, so about 2.2m stereo triangle is max I can have in the room for good sound. I would assume distance might be shorter if:
- one has small speaker with direct radiating tweeter, speaker whose DI is <6db around 1kHz.
- one has relatively little furnishing compared to room size
If still no perceived effect? my system / posts might be a crap shoot but I have some faith in Griesingers work and since it seems to happen in my place it ought to happen in your place too
Like anything written its hard to relate the message to anything meaningful if there is no auditory experience. This is something everyone needs to experiment themselves, with their own systems, to get the audio perception, to hear the one step transition to be able to recognize what good enough phase / harmonics sounds. I think this is one of the most important things for DIY loudspeaker folks to get experience on, something that gives perspective on anything else, anchor for relative importance of things. Have noisy unbraced bass box with leaking port? So long clarity. Have too much excursion and resulting IMD with the mid driver? Good bye recorded harmonics, and so on
This would be very great thing, think about it, the system needs to be good to have the clear sound at listening distance you wish with playback level you wish, quite clear target to strive for, common denominator that connects 99% of texts been written on the forum Ah well, sorry spamming about it
I'm just trying to get response from all of you what you think, encourage to test it and then write about it so I could relate my experience better.
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I'm terribly sorry for long poorly written posts with many smiley faces. In short, its about trying to perceive our selves what Griesinger writes about, which to me seems to be at core of loudspeaker hobby. It relates nicely to hifijims latest post as well.
Now, of to mid summer holiday
Now, of to mid summer holiday
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Hello All,
A few things to keep in mind:
The measurements posted here are gated, no real reflections were harmed by the test frequency sweeps.
Piston drivers have narrowing beams with increasing frequency.
Direct sounds are important to location and direction.
Piston drivers, waveguides and horns are aimed at the sweet spot(s).
Seats in a direct sound null are very much like a live theater seat with a column in the sight line to the stage.
A little food to chew on:
Take a look and play with this free software for a few minuets. Distance between mid and tweeter causes a phase change change.
Take a look at the relationships between SPL, phase, also crossover slopes, all these things effect the polar plots and your listening experience. Sound stage and all.
http://www.tolvan.com/index.php?page=/xdir/xdir.php
Thanks DT
One thing that I do as part of equalization is to place a test microphone where I will sit and play pink noise. While the time delay between the the mid and tweeter is adjusted with the crossover watch a RTA. You may not hear the phase change but you can see the SPL change up and down as the Peaks and Nulls move.
A few things to keep in mind:
The measurements posted here are gated, no real reflections were harmed by the test frequency sweeps.
Piston drivers have narrowing beams with increasing frequency.
Direct sounds are important to location and direction.
Piston drivers, waveguides and horns are aimed at the sweet spot(s).
Seats in a direct sound null are very much like a live theater seat with a column in the sight line to the stage.
A little food to chew on:
Take a look and play with this free software for a few minuets. Distance between mid and tweeter causes a phase change change.
Take a look at the relationships between SPL, phase, also crossover slopes, all these things effect the polar plots and your listening experience. Sound stage and all.
http://www.tolvan.com/index.php?page=/xdir/xdir.php
Thanks DT
One thing that I do as part of equalization is to place a test microphone where I will sit and play pink noise. While the time delay between the the mid and tweeter is adjusted with the crossover watch a RTA. You may not hear the phase change but you can see the SPL change up and down as the Peaks and Nulls move.
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