Re: Re: OB trap
Hi Eric,
I'm going to argue a little, based on experience and measurement.
As a slightly lazy and not terribly skilled DIYer, I built some OBs thinking they would be easier than boxes, for little cost in terms of performance. I was wrong on both counts.
After feeling the baffles had a tendency to vibrate I put on much more substantial "wings" to stiffen up the structure (and tried other tricks too).
When I had the wings on the cavity modes (which affect the cone motion as well as radiating backward) were becoming troublesome, the worst of them was not much different from a box mode, and stuffing a lot of wadding behind a dipole produces something that I was not aiming for. (I did not know about Orions, and only tried much less complex wing shapes - I should have done more research there.)
Also the filtering from the basket (since you bring it up) was a pain too, spoiling the dipole response. (In retrospect cardioid might be easier to approximate.)
Very "open" baskets and a thin, flat baffle were needed, but that means a floppy structure or exotic materials. I gave up.
I can accept that there can be good "dipole" loudspeakers (better call them OBs as even my electrostats are not perfect dipoles), if the radiation pattern they give (in reality) is wanted. To me it seems something of a myth that they are much easier to design/build (DIY, not kits, of course). The performance costs or features (as you like) are clear.
A box is naturally quite a rigid structure, internal bracing is fairly easy, and internal acoustic modes can be damped reasonably well if the box is intelligently shaped and sized for the frequency range covered. My latest boxes measure and sound better than my modest skills allowed me to achieve with an OB.
Obviously just my point of view, and offered in case someone would rather avoid repeating the experiment.
Ken
Eric Weitzman said:
Hi Eric,
I'm going to argue a little, based on experience and measurement.
As a slightly lazy and not terribly skilled DIYer, I built some OBs thinking they would be easier than boxes, for little cost in terms of performance. I was wrong on both counts.
After feeling the baffles had a tendency to vibrate I put on much more substantial "wings" to stiffen up the structure (and tried other tricks too).
When I had the wings on the cavity modes (which affect the cone motion as well as radiating backward) were becoming troublesome, the worst of them was not much different from a box mode, and stuffing a lot of wadding behind a dipole produces something that I was not aiming for. (I did not know about Orions, and only tried much less complex wing shapes - I should have done more research there.)
Also the filtering from the basket (since you bring it up) was a pain too, spoiling the dipole response. (In retrospect cardioid might be easier to approximate.)
Very "open" baskets and a thin, flat baffle were needed, but that means a floppy structure or exotic materials. I gave up.
I can accept that there can be good "dipole" loudspeakers (better call them OBs as even my electrostats are not perfect dipoles), if the radiation pattern they give (in reality) is wanted. To me it seems something of a myth that they are much easier to design/build (DIY, not kits, of course). The performance costs or features (as you like) are clear.
A box is naturally quite a rigid structure, internal bracing is fairly easy, and internal acoustic modes can be damped reasonably well if the box is intelligently shaped and sized for the frequency range covered. My latest boxes measure and sound better than my modest skills allowed me to achieve with an OB.
Obviously just my point of view, and offered in case someone would rather avoid repeating the experiment.
Ken
Correction!
Hi Eric,
No! I did not even for a moment consider *bass* reproduction using dipoles. All my comments were for speakers for >300Hz. Below that dipoles never made any sense to me (and I've got electrostats that were designed as - nearly- full range, and I've measured in room many times).
Subjective? Measure, measure, measure: ABX rules (at least when practical).
Ken
Eric Weitzman said:
Hi Eric,
No! I did not even for a moment consider *bass* reproduction using dipoles. All my comments were for speakers for >300Hz. Below that dipoles never made any sense to me (and I've got electrostats that were designed as - nearly- full range, and I've measured in room many times).
Subjective? Measure, measure, measure: ABX rules (at least when practical).
Ken
Ken,
The wings seem to be a big problem. I watched a few iterations near the end as a group of DIYers and Linkwitz tweaked and wrapped up his Phoenix DIY project about five years ago. They tried umpteen shapes and sizes until they got a response they could live with. This work and prior experience and knowledge seemingly made it into the Orions.
The midrange driver has a basket that's very open (to minimize filtering) yet stiff and correspondingly expensive. But it meets other criteria too, so the price is the losing tradeoff. The two woofers are mounted in opposite orientations so they don't have the asymmetry due to filtering problem.
I decided years ago to *not* try to design speakers. After getting a handle on the theory and then seeing how reality punches holes in it once a design is built, which causes a zillion iterations to get it right(?), I concluded it was not for me. Sort of like your OB experience, except I got there without getting my hands dirty.
- Eric
The wings seem to be a big problem. I watched a few iterations near the end as a group of DIYers and Linkwitz tweaked and wrapped up his Phoenix DIY project about five years ago. They tried umpteen shapes and sizes until they got a response they could live with. This work and prior experience and knowledge seemingly made it into the Orions.
The midrange driver has a basket that's very open (to minimize filtering) yet stiff and correspondingly expensive. But it meets other criteria too, so the price is the losing tradeoff. The two woofers are mounted in opposite orientations so they don't have the asymmetry due to filtering problem.
I decided years ago to *not* try to design speakers. After getting a handle on the theory and then seeing how reality punches holes in it once a design is built, which causes a zillion iterations to get it right(?), I concluded it was not for me. Sort of like your OB experience, except I got there without getting my hands dirty.
- Eric
Eric Weitzman said:
I have not heard an Orion, but would be interested to one day if given the opportunity. None of those so far encountered (OB's) have even given the slightest hint that I'd be interested in persuing them further. Even bad implementations of a good idea pique my curiousity and often get me researching and designing; my big horns for example after hearing some KHorns.
My reference for bass is uprights and baby grand pianos, which I hear regularly in the same room.
I am glad you enjoy your system, but that does not mean that I would.
PS: note my first post in this thread about audio being two hobbies.
Re: Correction!
@Ken
Sorry, I must have read through your post too fast. You quoted MaVo who definitely made that point, as did Brett (but more specifically and thoroughly in his quote).
@Brett
Since there was a slight run on "your" side of the (subjective) argument, I wanted to add some more (subjective) weight on the other.
The zealotry issue is certainly real, I won't dispute that. I'm a zealot, so sue me! You can even call me a fanboy or lemming as Krekovsky refers to Orion zealots.
But like most Orion owners, I reached the end of the trail after decades and decades of wandering from one technology to the other. Wasn't that the seed question for this thread, after all?
Our paths have been the opposite of each others': you've heard crappy OB and gone from K-horns to big horns. I've gone from crappy horns to good horns to Orions.
- Eric
kstrain said:
@Ken
Sorry, I must have read through your post too fast. You quoted MaVo who definitely made that point, as did Brett (but more specifically and thoroughly in his quote).
@Brett
Since there was a slight run on "your" side of the (subjective) argument, I wanted to add some more (subjective) weight on the other.
The zealotry issue is certainly real, I won't dispute that. I'm a zealot, so sue me! You can even call me a fanboy or lemming as Krekovsky refers to Orion zealots.
But like most Orion owners, I reached the end of the trail after decades and decades of wandering from one technology to the other. Wasn't that the seed question for this thread, after all?Our paths have been the opposite of each others': you've heard crappy OB and gone from K-horns to big horns. I've gone from crappy horns to good horns to Orions.
- Eric
Re: Re: Correction!
A couple of posts that state why they don't agree with a particular topology, compared to your numerous ones that go into great detail and length defending yours.
I'm off to do some soldering whilst I enjoy some music on my old series one Realistic mach Ones through an ancient Yamaha integrated.
Hilarious.Eric Weitzman said:
A couple of posts that state why they don't agree with a particular topology, compared to your numerous ones that go into great detail and length defending yours.
Sort of nauseating from this end, and the zealotry (of which I have been guilty in the past at times) is probably the greatet problem with hi-fi.Eric Weitzman said:The zealotry issue is certainly real, I won't dispute that. I'm a zealot, so sue me! You can even call me a fanboy or lemming as Krekovsky refers to Orion zealots.
I'm glad you're content, but that does not affect either of my points: I (so far) don't like OB's. And that I persue two hobbies, listening to music, as well as designing and building, not simply purchasing a finished product or design (for which I zealously need to defend my choice[/i])Eric Weitzman said:
I would never have changed my horns, except added some similarly voiced rears, but I had to move for work, and my home which has a huge open plan room was not able to make the 800km move with me. Sydney rental market does not allow the space chaply, and it's much different dealing with neighbour sound leakage issues as a tenant than an owner. So they were dismantled, and many of the parts sold, as it will be >4 years before I get the chance to move home, maybe longer. It's been 4 years already.Eric Weitzman said:
I'm off to do some soldering whilst I enjoy some music on my old series one Realistic mach Ones through an ancient Yamaha integrated.
Re: Re: Re: Re: Re: Re: designs vs. results
I tend to agree it is all very subjective a raltive as well. These reports that are not able to provide more detail description only show that they do not know what real instruments should sound like, and thus cannot provide a detailed enough evaluation. It is also writers that don't know much that like to throw thier weight around.
graaf said:
"energy and excitement" or "coloration and resonances"?
for many Quad ESL and many more are also "boring", "uninvolving" and lacking in "energy and excitement"
it is all very subjective, very relative
best,
graaf
I tend to agree it is all very subjective a raltive as well. These reports that are not able to provide more detail description only show that they do not know what real instruments should sound like, and thus cannot provide a detailed enough evaluation. It is also writers that don't know much that like to throw thier weight around.
Quality reviewers should be able to pinpoint more precisely what is good and what is not correct, which music passages, what instruments were good, what had problems and where the problems in the music occurred.soongsc said:
sorry for the previous faulty post...
QUOTE]Originally posted by kstrain
When I had the wings on the cavity modes (which affect the cone motion as well as radiating backward) were becoming troublesome, the worst of them was not much different from a box mode, and stuffing a lot of wadding behind a dipole produces something that I was not aiming for. (I did not know about Orions, and only tried much less complex wing shapes - I should have done more research there.)
Also the filtering from the basket (since you bring it up) was a pain too, spoiling the dipole response. (In retrospect cardioid might be easier to approximate.)
Very "open" baskets and a thin, flat baffle were needed, but that means a floppy structure or exotic materials. I gave up.
[/QUOTE]
Hi kstrain,
sometimes people claim OB to be more easy to design than
"boxes". This is far from truth. Design of a well performing OB
is a challenge in fact.
You mentioned some of the practical problems:
- thin and flat baffle which provides rigidity ?
- true dipole behaviour with asymetrical forward and backward
radiation of a typical dynamic driver ?
To achieve smooth polar response, the baffle cannot be
much wider then twice the diameter of the driver ...
How to compensate the low frequency cutoff introduced
by such a small baffle then ?
How to avoid the baffle step or how to compensate for ?
How to approximate dipole or cardioid response over a wide
frequency range ?
I also agree that wings on a baffle introduce modes that can
be worse in audible effect than those of a closed box ...
This design has an answer to ALL of those questions, even
though these answers are not the only ones possible ...
dipol-audio.de
But if one does not account for all of the problems mentioned
above, a deficient OB design is the result, which most likely
cannot play off against a conventional "box" design.
I credit your practical experience with OB and the fact that
you do not blame the flaws of your first attempt to the
principle ... you have seen the critical points in practical design
very well and they do agree with my experience.
QUOTE]Originally posted by kstrain
When I had the wings on the cavity modes (which affect the cone motion as well as radiating backward) were becoming troublesome, the worst of them was not much different from a box mode, and stuffing a lot of wadding behind a dipole produces something that I was not aiming for. (I did not know about Orions, and only tried much less complex wing shapes - I should have done more research there.)
Also the filtering from the basket (since you bring it up) was a pain too, spoiling the dipole response. (In retrospect cardioid might be easier to approximate.)
Very "open" baskets and a thin, flat baffle were needed, but that means a floppy structure or exotic materials. I gave up.
[/QUOTE]
Hi kstrain,
sometimes people claim OB to be more easy to design than
"boxes". This is far from truth. Design of a well performing OB
is a challenge in fact.
You mentioned some of the practical problems:
- thin and flat baffle which provides rigidity ?
- true dipole behaviour with asymetrical forward and backward
radiation of a typical dynamic driver ?
To achieve smooth polar response, the baffle cannot be
much wider then twice the diameter of the driver ...
How to compensate the low frequency cutoff introduced
by such a small baffle then ?
How to avoid the baffle step or how to compensate for ?
How to approximate dipole or cardioid response over a wide
frequency range ?
I also agree that wings on a baffle introduce modes that can
be worse in audible effect than those of a closed box ...
This design has an answer to ALL of those questions, even
though these answers are not the only ones possible ...
dipol-audio.de
But if one does not account for all of the problems mentioned
above, a deficient OB design is the result, which most likely
cannot play off against a conventional "box" design.
I credit your practical experience with OB and the fact that
you do not blame the flaws of your first attempt to the
principle ... you have seen the critical points in practical design
very well and they do agree with my experience.
gedlee said:
Now I see
But I must admit that I don’t know if I understand well Your explanation
rather I am quite sure that as a technical laymen I don’t
Let me ask You a few more questions.
I am not quite convinced that we can in the same way qualify (as equally sound degrading) and explain (i.e. the distortion mechanism) of all kind of VER (very early reflections) i.e. those delayed <2 ms (or <5 ms? Am I correct?)
Can it be that not all kind of VER have the same audibility threshold? Can it be dependent e.g. on the frequency content of particular reflection and on its delay time?
Can it be that VER of frequency content centered at low frequencies are less audible? I mean less prone to become unmasked?
Can it be that VER of frequency content deviating significantly from the frequency content of the direct sound (as in case of diffraction off the cabonet edges) are more audible?
Can it be that VER having the same frequency content as the direct sound are less audible? I mean less prone to become unmasked?
Can it be that lateral VER are more audible then vertical? mean taking into account that our binaural hearing has higher time resolution.
Can it be that VER of the last two mentioned kinds (i.e. vertical and "having the same frequency content as the direct sound" or perhaps rather "the same group delay as the direct sound") are relatively inaudible and harmless if they are delayed less then 1 ms? I mean they are effectively masked?
I ask those questions because I have experience with one-way (wide range driver) omnidirectional loudspeakers positioned practically against the front wall (the axis of the driver is less than 15 cm from the wall). They are very short and positioned very low on the floor - the driver is about 20 cm above the floor, firing upwards.
Since the wall is hard and reflective I should have a lot of vertical VER delayed less than 1 ms.
The "problem" is that I don’t experience nothing problematic, nothing unpleasant that I can attribute to VER, no "mucking up the image" etc.
Perhaps I listen to music at too low SPLs to experience VER distortions at audible levels?
What is the SPL threshold for VER distortions to become audible?
Is the SPL threshold dependent on a kind of VER? I mean in terms of amount of the delay, being lateral or vertical, frequency content and so on.
My loudspeakers are somewhat similar to Stig Carlsson designs such as OA-52 (image attached, the shorter one). These are also very short (midbass driver is about 25 cm above the floor level) and designed to be positioned against the wall.
And all this "to reduce harmful early room reflections" (sic!)
Nevertheless the Carlssons use some acoustic absorbers to reduce the amount of VER coming from the wall. We can imply from that that their designer was aware of the problem. But He considered that it is sufficient to reduce the amount of VER.
In case of my loudspeakers the situation is a bit different because the wide range driver is certainly beaming which certainly affects the frequency content of VER.
Additionally, with this beaming and signifficant rounding up of all of the cabinet edges I have probably no audible problem with enclosure diffraction.
Moreover there is no crossover with its inherent group delay problems.
But how are all this factors affecting the situation with regards of audibility of VER distortions I really don’t know.
I only know that adding absorbers (going the Carlsson suggested way) doesn’t change it. With or without the absorbers I can’t really hear any kind of particular sound degrading distortion which I could attribute to VER.
Can it be that in my particular case VER are effetively masked?
Taking into account:
- unusual loudspeakers with no diffraction and crossover-related group delay problems (although the driver itself certainly has group delay problems on frequency extremes)
- verticality of the VER
- the beaming of the driver affecting spectral content of the VER (which are obviously "low passed")
- very short time of delay <1 ms
best,
graaf
Attachments
graaf said:
Thats too many questions to answer one by one, but the gist of them are questions regarding the thresholds and audibility of a myriad of small facets of the VER. The basic answer is that we just don't know. The experiments that have been down were very simplistic and tend to lead to areas of further research rather than complete answers.
What is know is this. The group delay effect is dominate above about 1 kHz and tails off above about 6 kHz. At low frequencies there is virtually no effect. It is very dependent on the delay time and the level of the effect as well as the level of the playback. So in all likelyhood it is dependent on all those aspects that you asked about.
So what I must conclude from this is that above 1 kHz it would be wise to minimize these VER as much as possible - simply because I don't have enough information to determine tradeoffs. As they are minimized it appears that sound quality just gets better - but this is subjective without strong objective support except for the simple experiments that have been done.
What is pretty conclusive, after a multitude of experiments by myself and other, is that THD and IMD have absolutely nothing to do with sound quality and it is probably best just to ignore these numbers even if we don't necesarily ignore nonlinearity altogether. For example, I use bandpass subs because they acoustically low pass the output. This reduces the higher harmonic content. Whether this lowers the THD or IMD I have no idea - I've never measured it - there would be no point. So while I don't ignore nonlinearity altogether, I do not waste my time measuring or talking about THD.
As to your specific example, there is no way that I can comment on a single subjective experince, especially one that is derived from ones own designs and or setups. There is far too much potential for bad data in a case like this. From what you described there would likely be very few VERs above 1 kHz. in that setup. Thats about all I can say.
Thanks for the polite conversation - its been pretty rare in this thread as of late.
Why don't you start a thread on "distortion perception" so that we can get this interesting conversation away from the OB topic domination that has occured.
gedlee said:
maybe I will start it but I would really need more time to "moderate" it
and big thanks for this conversation goes to You in the first place!
for Your patience for my not always wise questions and for Your very informative posts!
and for all those "nervous" guys irritated because someone else has different opinion or more experience or knowledge I have an advice below
irritation can be a good thing when forces someone to think
all is needed is genuine interest in the discussed matter and a little humility
after all we don't differ that much from oysters
best,
graaf
graaf said:
maybe I will start it but I would really need more time to "moderate" it
I will start a post, next week. I'm far too busy this weekend. Going to a Redwings playoff game today!! How cool is that!! The first playoff game that I have ever seen. My son plays hockey now, so he is ecstatic. Go Wings!!
gedlee said:
Nope.
..and IM which always is a result from a non-linear transfer curve.
Yes, if it's hifi we're talking about.. and that is not possible with a transfer curve that gives 5%HD. Colorations is something that some (not all) people prefer but it ain't hifi.
That is not true. There are people that understand the need for low distortion in hifi audio.
In the thread about listening fatigue you wrote this;
Could it be that it's the price you pay for moving to high spl/high distortion speakers?
I now that in my neck of the woods people that switch to systems that can handle high spl's AND have low distortion can listen longer than ever. Low distortion equals relaxed sound if the program material deliver.
Also this statement seems like a little contradiction to what you have written earlier;
About;
I don't think we have to guess. The major reasons for fatigue as wieved from the imperfections in the recording-playback-chain is non pleasing frequency response either from the gear or the material. High levels of high order distortion, crossover distortion, audible resonances, intermodulationdistortion. The massaker of CD's in the mastering studios is one of the all time biggies. Vinyl often are handled with more care.
/Peter
Brett
(y’day):
> A couple of posts that state why they don't agree with a particular topology, compared to your numerous ones that go into great detail and length defending yours.
IMO, Eric takes the trouble to properly explain his views.
Originally posted by Eric Weitzman
The zealotry issue is certainly real, I won't dispute that. I'm a zealot, so sue me! You can even call me a fanboy or lemming as Krekovsky refers to Orion zealots.
posted by Brett
Sort of nauseating from this end, and the zealotry (of which I have been guilty in the past at times) is probably the greatet problem with hi-fi.
Having heard the Orions, I think some of the zealotry is justified.
Yes, zealotry is one the greatest problems with many things. zealotry + politics , or zealotry + religion can > war
Peace
(y’day):
> A couple of posts that state why they don't agree with a particular topology, compared to your numerous ones that go into great detail and length defending yours.
IMO, Eric takes the trouble to properly explain his views.
Originally posted by Eric Weitzman
The zealotry issue is certainly real, I won't dispute that. I'm a zealot, so sue me! You can even call me a fanboy or lemming as Krekovsky refers to Orion zealots.
posted by Brett
Sort of nauseating from this end, and the zealotry (of which I have been guilty in the past at times) is probably the greatet problem with hi-fi.
Having heard the Orions, I think some of the zealotry is justified.
Yes, zealotry is one the greatest problems with many things. zealotry + politics , or zealotry + religion can > war
Peace
Re: Re: Re: Re: Re: Re: designs vs. results
Not criticising your speakers anymore than your questioning my design motives re: OB... I was quoting my daughters 19 yo boyfriend, as in "PA speakers may be butt ugly but they can kick #$@".. hence the smiley
Feel free to criticise my speakers... I've got a thick skin and maybe I can improve them. I'm actually kinda fond of the industrial look...
John L.
gedlee said:
Not criticising your speakers anymore than your questioning my design motives re: OB... I was quoting my daughters 19 yo boyfriend, as in "PA speakers may be butt ugly but they can kick #$@".. hence the smiley
Feel free to criticise my speakers... I've got a thick skin and maybe I can improve them. I'm actually kinda fond of the industrial look...
John L.
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