You haven't "heard" any speakers with obvious issues?
And we know how full of BS this hobby is
There's a lot more in mainstream HiFi.
jeff
Anyhow, I started this thread because I'm not sure I've seen any evidence that box colourations are a real issue, there isn't any measurement data to show that it's an issue (except perhaps in facetious examples). And we know how full of BS this hobby is
I'm not sure why you feel the need to move beyond this paragraph. There have been some assertions of an "issue" but no actual evidence to support them. The closest thing presented to evidence, a blind preference test of three speakers, did not show that listeners latched onto anything about the OB speakers' presentation, pro or con.
There are "persistent reports" about the "sound" of different wires, too. I wouldn't put much stock in "persistent reports."
It sounds like you're trying to convince yourself, despite any evidence for the claim, more than anything else.
I'm basically convinced that the primary issue is simply that people see the fronts and the backs of the drivers, and have convinced themselves that's the way it's supposed to be. That, and nothing having to do with "box colorations," but image diffusion from the backwave reflecting off the front wall.
But this is DIY, so build it and try for yourself. My experience with the (SL-designed) Audio Artistry Dvorak, and hearing SL's latest Orions at AXPONA, have not by any means convinced me that OB is worth the compromises required in design and placement. To me, at least.
Nah, let's just use shoeboxes...
Well, then, all the work B&W and KEF and newer companies like Magico have put into their enclosures (along with what we've done at Holistic Audio) is really just for show. Yup, that must be it. Gives us a marketing angle. Or maybe not.
Let's go ahead and start using shoeboxes instead, and while we're at it let's also use some of those really great 1200 Watt PMPO transistor radio amps... or wait... maybe they already exist. Yes, they do! Boomboxes! Let's all drop this BS hobby and run out to buy boomboxes! As an upgrade, may I suggest a Bose Wave Radio?
You say you can't hear the difference? Eh? What's that you're saying?
Ah the perils of having an open forum... just can't keep the deaf-men foolishness from invading nearly every thread.
As an interesting aside, there is some research that seems to indicate that roughly 30% of the general population really and truly cannot discern between a really fine wine and the uber-cheap stuff. "Normal" people can educate their palate and learn the differences, but these 30% cannot.
I'm beginning to wonder if the same applies to the audio world, and if the figures are more like 50%. In which case, the continued popularity of boomboxes and wave-radio is easier to understand.
Only if you are from the 30% camp, please get off the "can't hear any difference anywhere" soap-box and go build model airplanes or something where you CAN tell the difference. 'Nuff said.
Well it looks like some people JUST CAN'T HEAR IT, so then obviously if they cannot notice the difference, well then NOBODY ELSE should be able to either... right? Them's the rules! (Hey, peer pressure worked great during the inquisition, we should be able to get it to work again, right?)
Well, then, all the work B&W and KEF and newer companies like Magico have put into their enclosures (along with what we've done at Holistic Audio) is really just for show. Yup, that must be it. Gives us a marketing angle. Or maybe not.
Let's go ahead and start using shoeboxes instead, and while we're at it let's also use some of those really great 1200 Watt PMPO transistor radio amps... or wait... maybe they already exist. Yes, they do! Boomboxes! Let's all drop this BS hobby and run out to buy boomboxes! As an upgrade, may I suggest a Bose Wave Radio?
You say you can't hear the difference? Eh? What's that you're saying?
Ah the perils of having an open forum... just can't keep the deaf-men foolishness from invading nearly every thread.
As an interesting aside, there is some research that seems to indicate that roughly 30% of the general population really and truly cannot discern between a really fine wine and the uber-cheap stuff. "Normal" people can educate their palate and learn the differences, but these 30% cannot.
I'm beginning to wonder if the same applies to the audio world, and if the figures are more like 50%. In which case, the continued popularity of boomboxes and wave-radio is easier to understand.
Only if you are from the 30% camp, please get off the "can't hear any difference anywhere" soap-box and go build model airplanes or something where you CAN tell the difference. 'Nuff said.
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Nobody said that.
There are obvious issues, such as diffraction (also present in OBs, and to a larger degree at that!) and cabinet volume. But few boxes are so poorly designed/built so as to lead to any general "box coloration." (Except, again, perhaps, with large planar midranges.)
So that suggests one should figure out the appropriate volume, and worry more about rounding over any sharp edges than erecting heroic amounts of internal bracing.
Which reminds me, there was another blind test pitting an excellent OB-ish speaker (my favorite of the genre, Gradient's Revolution) against the GedLee Summa. The result was the same: inconclusive. See a little more on this thread.
As for B&W, what they do it seems to me (based on hearing their speakers) seems to mostly be marketing. When they come out with something worth hearing, maybe I'll care more.
KEF is a more serious firm for sure, but they are as driven by the need to differentiate themselves in the marketplace through industrial design as anyone. It's also worth noting that their Q900 has an indifferent-at-best box, but what audible problems it has (I've never heard a commercial speaker that cheap sound so good) result from the lack of control over the midwoofer's break-up, not "box colorations."
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Not asking anyone to believe, just telling you what I have experienced.
I recommend you try some simple but effective testing as I have. While still in the rough box stage stage a 'back-on, back-off' test might give you some insight.
I do not subscribe to those. I have tested and found the connections to have more effect than the wires.
Try the back-on, back off test and report back.
A man after my heart.
One would be a fool to think that. Even simple testing is effective.
I am amazed too.
I won't say that, I just suggest they try.
As a side note one has to consider XO point and wave length before they simply pull the back off any old mid cabinet. We wouldn't want cancellation to affect our judgement would we?
I assume that's a joke.
Right?
And what makes you think I haven't done the test you suggest? It's not revealing of much, except for how little bass OB speakers have without EQ and how badly designed some drivers are (mechanical noise). It certainly doesn't point the way to some "box coloration," which to date has not been shown as anything except one of those audiophool idiocies that magically seems to disappear in blind testing.
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I have heard speakers that I don't feel sound quite as I would like, but I can't say what the cause is in each case.
No, I'm just trying to learn from others by reading, saves me a huge commitment of time etc. to build a lot of speakers. People say they hear colourations, say they have built OB and boxes and at the end they prefer OB. If it's because of colourations I would prefer to see measurements that support this.
Not many people are willing to listen to others to find the better way forward - but I'm lazy enough
unfortunately my ears are fussy - I've already got a number of commercial and some DIY full range speakers, but I haven't got the sound I want yet !
fyi - I'm looking at making a single mono speaker a source of sound for an open concept house. Stereo imaging is neither required or that feasible and room treatments won't be considered.
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Not at all.
I trust that you have considering your tone.
You'll note that I was discussing mids only, I am not a fan of OB bass, as previously mentioned.
I cannot comment on that.
Everybody has a preference, and mine has turned to be OB. I love the openess. And I have seen some really impressive speakers on this thread! Having said that you might be interested in seeing what Decware has to offer. Let me try to post a photo of the speaker. I will look for better images so that you can see this better.
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I built many and continued to listen to others and their opinions along the way. This is why I am comfortable in my convictions.
What I am relating is that I am not concerned about panel resonance when I use 3/4" ply for a mid box, I am not concerned with floor bounce or other reflections. I am talking about the "box effect" on the mids, call it what you want.
Less coloration with OB?
When it comes to comparing OB panels vibrating alone vs panels vibrating AND internal resonances as happens with most boxes, solid mechanical design, along with appropriately placed braces and well designed internal damping structures can greatly reduce the colorations in either case.
The caveat here is just how freakin' DIFFICULT it can be to get those internal box resonances to just go away. I've spent years devising solutions to absorb or manage the back-wave and finally came up with something that worked very well for my H3 speakers. But it's difficult and time consuming to implement these kinds of internal structures, and more so when you're using double-walled tubes. But yes, it can be done, it IS possible to create "enclosure" type speakers which show vanishingly low cabinet vibration and almost complete back-wave absorption... and along with years of R&D it comes at a very high cost.
So then why have I turned to OB speakers for the next generation? The short and simple explanation is that when properly designed, an OB system creates much less excitation of lateral and vertical resonances in the room. And the difference is CLEARLY audible.
Unless you're willing to invest TONS of money into the room (I am most definitely NOT wiling to do that), it pays to have a room-friendly speaker.
Let me illustrate with an example based on two speakers that I know really well, because I built them:
Exhibit A)
my reference system, being DEQX based, is flat +/- 0.2dB from 30 Hz to 20KHz, it's fairly efficient and completely time-coherent, top to bottom. Great! It's omni-directional and has wonderful imaging. Great! It is way more room friendly than most. Great!
But you know what? my living room is notoriously bad and HAS SOME NASTY RESONANCES which require HUGE amounts of parametric EQ and the use of an additional DEQ2496 to tame the resonances.
Once it's properly eq'd, this system is incredible. But without the special room tuning, it's just not as good.... in my listening room there are some modes that just muck up the vocal range so bad that when Joni Mitchell sings she sounds like she's in a barrel.
Lots and lots of eq work had to be done to fix this. Did I say lots? What I really meant to say was TOO DANG MUCH!!
Now we look at Exhibit B,
my most recent model which is an OB panel speaker using a full-range and a woofer in a time-aligned FAST type of arrangement.
Like my reference model, it also uses a lot of DSP to correct the timbral imbalances from the drivers, and in doing so attains 40Hz to 20KHz +/- 0.5dB in anechoic conditions. It is also time-coherent and fairly efficient and has wonderful imaging. Great! And it is fairly constant in its directional characteristics, not exactly CD but close enough. Great!
So guess what happens when you put it in the same lousy room? The sound remains great, WITHOUT the need for ANY room eq or treatments.
Now Joni Mitchel doesn't have a chesty voice anymore! The actual in-room response is within +/- 3dB in the SAME lousy room!
So look at the graphs of anechoic (actual FR w. distortion measurement) vs in-room... almost no need for special room treatment or additional room eq in almost ANY room. The new system is 10X less expensive than my reference, nearly equals it in anechoic performance and is clearly better in most rooms unless one is willing to pay for maybe a week's worth of eq'ing and fine-tuning.
In a head to head comparison, without room eq, it's hands down a better speaker. With room EQ, it's dangerously close to the reference model, at 1/10th the price.
Does this mean OB is necessarily better? Not at all. But I will venture this opinion informed by experience: when properly executed, a good OB speaker will be MUCH easier to use and sound much better in many more rooms than most other types, simply because they have much less interaction with the room resonances. (At the frequencies where they count the most!)
OB rules!
When it comes to comparing OB panels vibrating alone vs panels vibrating AND internal resonances as happens with most boxes, solid mechanical design, along with appropriately placed braces and well designed internal damping structures can greatly reduce the colorations in either case.
The caveat here is just how freakin' DIFFICULT it can be to get those internal box resonances to just go away. I've spent years devising solutions to absorb or manage the back-wave and finally came up with something that worked very well for my H3 speakers. But it's difficult and time consuming to implement these kinds of internal structures, and more so when you're using double-walled tubes. But yes, it can be done, it IS possible to create "enclosure" type speakers which show vanishingly low cabinet vibration and almost complete back-wave absorption... and along with years of R&D it comes at a very high cost.
So then why have I turned to OB speakers for the next generation? The short and simple explanation is that when properly designed, an OB system creates much less excitation of lateral and vertical resonances in the room. And the difference is CLEARLY audible.
Unless you're willing to invest TONS of money into the room (I am most definitely NOT wiling to do that), it pays to have a room-friendly speaker.
Let me illustrate with an example based on two speakers that I know really well, because I built them:
Exhibit A)
my reference system, being DEQX based, is flat +/- 0.2dB from 30 Hz to 20KHz, it's fairly efficient and completely time-coherent, top to bottom. Great! It's omni-directional and has wonderful imaging. Great! It is way more room friendly than most. Great!
But you know what? my living room is notoriously bad and HAS SOME NASTY RESONANCES which require HUGE amounts of parametric EQ and the use of an additional DEQ2496 to tame the resonances.
Once it's properly eq'd, this system is incredible. But without the special room tuning, it's just not as good.... in my listening room there are some modes that just muck up the vocal range so bad that when Joni Mitchell sings she sounds like she's in a barrel.
Lots and lots of eq work had to be done to fix this. Did I say lots? What I really meant to say was TOO DANG MUCH!!
Now we look at Exhibit B,
my most recent model which is an OB panel speaker using a full-range and a woofer in a time-aligned FAST type of arrangement.
Like my reference model, it also uses a lot of DSP to correct the timbral imbalances from the drivers, and in doing so attains 40Hz to 20KHz +/- 0.5dB in anechoic conditions. It is also time-coherent and fairly efficient and has wonderful imaging. Great! And it is fairly constant in its directional characteristics, not exactly CD but close enough. Great!
So guess what happens when you put it in the same lousy room? The sound remains great, WITHOUT the need for ANY room eq or treatments.
Now Joni Mitchel doesn't have a chesty voice anymore! The actual in-room response is within +/- 3dB in the SAME lousy room!
So look at the graphs of anechoic (actual FR w. distortion measurement) vs in-room... almost no need for special room treatment or additional room eq in almost ANY room. The new system is 10X less expensive than my reference, nearly equals it in anechoic performance and is clearly better in most rooms unless one is willing to pay for maybe a week's worth of eq'ing and fine-tuning.
In a head to head comparison, without room eq, it's hands down a better speaker. With room EQ, it's dangerously close to the reference model, at 1/10th the price.
Does this mean OB is necessarily better? Not at all. But I will venture this opinion informed by experience: when properly executed, a good OB speaker will be MUCH easier to use and sound much better in many more rooms than most other types, simply because they have much less interaction with the room resonances. (At the frequencies where they count the most!)
OB rules!
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That's a good driver.
Decware is "modifying" the Dayton PS220 and using it with their Zen OpenBox + bass resonator. I've heard this and it does some things very well. In fact, it got me experimenting with the Dayton PS220 in an OB with a bass augmenting driver, and then I decided to play with DSP based Timbral Correction for the system to see if I could get better response than Decware was with their mods. The result was so excellent I've decided to start offering it as a kit. I'll try to create a post in the Vendor section to give more details.
Decware is "modifying" the Dayton PS220 and using it with their Zen OpenBox + bass resonator. I've heard this and it does some things very well. In fact, it got me experimenting with the Dayton PS220 in an OB with a bass augmenting driver, and then I decided to play with DSP based Timbral Correction for the system to see if I could get better response than Decware was with their mods. The result was so excellent I've decided to start offering it as a kit. I'll try to create a post in the Vendor section to give more details.
Your graphs seem to indicate the opposite is true? The in-room response looks pretty scary below 100Hz, even with such a high amount of smoothing.
I always enjoy Jack Caldwell's contributions. It makes sense that open baffle with its bass rolloff is going to make a room boom less. I don't know what the mathematical bass rolloff is. 12dB per octave?
Steen Duelund: How to build to the limits of possibility favours overdamped (Q= 0.5) closed box. Not quite acoustic suspension, the box is bigger, but strong magnet and low Fs and Qt. I suppose this is as near as you get to infinite baffle, but the idea is you can match the 12dB rolloff with the approximate 12dB rise in room resonance.
Since the topic is box colouration, diagram 5 illustrates a waterfall of time delay on a cheapish 218x275x400 mm Usher 701 reflex speaker with an unpleasant boxy resonance at around 850Hz. This appears to be all three sides standing waves peaking at the same time, since the box disobeys the classic 0.618:1:1.618 ratio which pushes resonant coincidences up to the 5th harmonic at 2000Hz.
With closed box, it wouldn't be hard to add some damping stuffing, but a reflex, IMO, just has to live with it.
Steen Duelund: How to build to the limits of possibility favours overdamped (Q= 0.5) closed box. Not quite acoustic suspension, the box is bigger, but strong magnet and low Fs and Qt. I suppose this is as near as you get to infinite baffle, but the idea is you can match the 12dB rolloff with the approximate 12dB rise in room resonance.
Since the topic is box colouration, diagram 5 illustrates a waterfall of time delay on a cheapish 218x275x400 mm Usher 701 reflex speaker with an unpleasant boxy resonance at around 850Hz. This appears to be all three sides standing waves peaking at the same time, since the box disobeys the classic 0.618:1:1.618 ratio which pushes resonant coincidences up to the 5th harmonic at 2000Hz.
With closed box, it wouldn't be hard to add some damping stuffing, but a reflex, IMO, just has to live with it.
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True, and if you switch off the amp, room boominess is completely gone
It does seem a bit like throwing out the baby with the bathwater.
I would love to have my bass as scary as that!
Really? How do you like this:
An externally hosted image should be here but it was not working when we last tested it.
8 locations spaced by 1ft. Dual subs plus right main.
only three sources in modal range? closed? looks good, but really if you look at the JC graph it is not bad at all - there is some 6db roll off below ~100Hz which can be easily equalized and of course nothing below fundamental mode (I suspect the 20Hz peak is not really there?) one relatively shallow dip, if he used 60dB range as you do, it would look much nicer