Is there such a thing as "box sound"?

[voodooless]

So, in this case different midrange drivers have been tested under usual circumstances (enclosure volume) against each other after frequency response correction? That is not quite what I was referring to, in my case, the very same drivers were used, the only difference was how they interacted with the enclosure volume.

Yes, its diffrent drivers, but in the same volume, so effectively the Qs of these combinations will also be all different. The fact that the box is the same, and the different Qs don't seem to impact sound, just reinforces my point.

As mentioned, the whole thing is not a minimum-phase system. You could correct for the frequency response, but particularly decay, as visible in the waterfall plot, persisted being completely different, particularly with the open-baffle arrangement.

Sure, the whole thing is not. Which is exactly my point: the Q is not the deciding factor here, but all the other interactions that happen due to the box volume differences.

Qtc is a result of driver + enclosure. In the particular case, the open-baffle variant stood out, producing a different perception of timbre despite from identical anechoic response.

I'm not doubting that at all. The discussion was about diffrent Qs of the closed box.

But there are different absorption grades in the bass bands (think of unwanted resonators of all kind), and there is different decay at different frequencies. Both make it illogical that a perfectly flat response would always be the right goal, and would guarantee identical sound perception. That is not the case in my experience.

Again, this was about different Qs on a closed box. The same driver in the same room in a different box will not have different absorption patterns and decays if you match the frequency responses. The only diffrence will be in the interactions with the box itself, like absorption performance, resonances, etc. I'm sure the room interaction of an open baffle speaker with the room are diffrent, and therefore there will be audible differences.

 

[terryforsythe]

Very much depends on other driver properties, like Vas. There are some pretty common compact midwoofers with Qts>0.5 but rather restricted Vas, which are suitable for vented systems and are commonly used for this purpose (can check for examples by Wavecore and Peerless).

There are all sorts of designs out there. Yes, some people do use high Qts woofers in ported enclosures, but that does not mean that it is the optimal solution.

Long ago I experimented with two prototypes of a 6.5" woofer, the only difference being the spider stiffness. They both had the same basket, cone, surround and motor structure. The unit with the stiffer spider had a Qts of 0.65 and a higher fs, the unit with the looser spider had a Qts of 0.4 and a lower fs.

For each prototype I designed a ported enclosure targeting a VL of 0.7. The woofer with the Qts of 0.65 required a 1.5 cu. ft. (~ 42L) enclosure and had an f3 in the low-mid 50s, while the woofer with a Qts of 0.4 required a 1 cu. ft. (~ 28L) enclousure and had a lower f3, extending into the low 40s if I remember correctly. It was nearly 4 decades ago, I don't remember the exact frequencies nor the alignments I used, though I do remember the physical enclosures. I also remember that the subjective difference in bass response was not insignificant - the unit with the 0.4 Qts and smaller enclosure definitely had more authority in the low bass.

 

[Arindal]

the Q is not the deciding factor here, but all the other interactions that happen due to the box volume differences.

I can agree to that, and yes, Q is only one factor at play here, and I am not claiming to be the decisive one if isolated. I mentioned this example rather to show that there are things interaction between cone driver and air in the enclosure, which contribute to differences in sound quality apart from frequency response and directivity.

The discussion was about diffrent Qs of the closed box.

Closed box usually refers to bass alignment, and yes I would agree that within a reasonable tolerance band, differences in bass Q would not be audible if corrected for frequency response and not exceeding extreme values (like Q=1.2 or higher).

I also remember that the subjective difference in bass response was not insignificant - the unit with the 0.4 Qts and smaller enclosure definitely had more authority in the low bass.

This is to be expected with different port tuning frequencies, which I would see as the main reason for differences if you corrected for frequency response and lower cutoff frequency electronically. It not, well, you have your answer.

Long ago I experimented with two prototypes of a 6.5" woofer, the only difference being the spider stiffness. They both had the same basket, cone, surround and motor structure. The unit with the stiffer spider had a Qts of 0.65 and a higher fs, the unit with the looser spider had a Qts of 0.4 and a lower fs.

I would expect such two units to behave differently as they are different drivers, not only because of Qts and Fs.

Somewhere in my box with drivers I have two tiny 3" midwoofers with identical basket, diaphragm, Fs and most other parameters, just Qts is different. Maybe should do some experiments with these, as the corresponding passive radiators can easily be tuned.

 

[voodooless]

I can agree to that, and yes, Q is only one factor at play here, and I am not claiming to be the decisive one if isolated. I mentioned this example rather to show that there are things interaction between cone driver and air in the enclosure, which contribute to differences in sound quality apart from frequency response and directivity.

Glad we can agree on that . But all this boils down to is: a crappy box is a crappy box

 

[terryforsythe]

This is to be expected with different port tuning frequencies, which I would see as the main reason for differences if you corrected for frequency response and lower cutoff frequency electronically. It not, well, you have your answer.

DSP can do a lot, including, to a certain extent, compensating for design flaws. But, back then DSP was not in widespread use in audio, and the cost was out of reach for most consumers. EDIT: At that time PEQ was not even very common - it mainly was old school graphic equalizers.

 

[ZolaIII]

DSP can do a lot, including, to a certain extent, compensating for design flaws. But, back then DSP was not in widespread use in audio, and the cost was out of reach for most consumers. EDIT: At that time PEQ was not even very common - it mainly was old school graphic equalizers.

O they had semi costume PEQ's (fixed to boxes frequency) cuple mW gain pasive tube one's.

They were expensive and this one whose so good that it's cloned and emulated even today.

 

[DSJR]

Maybe of no concern here at all, but in my time, especially when we had those things called 'comparators' for speakers all set in a line that we could switch between instantly, how some had an 'awww' sound in the mids, others an 'ahhh' or 'ehhh' colouration, easily heard too using pink noise as sound source and often noticed on voice. We only had panel-style dipoles back then (Quad, KLH 9s, early Acoustat and later on, Apogee, Magnaplanar and ML models), but I don't recall any of them having the same kind of colourations in the midrange at least as many, but not all in fairness, box models.

Yes, subjective, and peeps here will no doubt dismiss it. I've no idea how much is/was down to response issues at the time, but I remember a then noted speaker designer showing us how every speaker we had on dem that used the then-popular KEF B200 bass-mid driver, had a kind of 'hollow' cupped-hands sound to it, masked better in some speakers than others, but there nonetheless on voice when compared to its peers not using that driver (Spendor BC1, Rogers LS3/5 and Export Monitor and so on). The better AR speakers we had, kept their slightly nasal 'neh' sound to a minimum, the 10 pi model being exceptionally open and natural I recall.

Apologies for the subjective memories above. maybe other dealers well used to demming different speakers in direct comparison may have similar experiences?

 

[Pareto Pragmatic]

I would match the levels with the electronics. I would spend time simulating the bass responses before buying any components. I use VituixCAD, but there are a number of other programs that should serve the purpose of simulating bass response.

I am convinced. Thanks for taking the time with me and in the thread.

But I imagine that some (many) OB people would say you are using different drivers and that's what we are hearing, so it is not a good test of the box effect. And if we took my approach, they would say the OB design is bad, so it's not a fair test of the box effect.

I doubt anything would be a fair test of the box effect for those who hear "boxiness" and hype OB designs as the best (not best for some things, some rooms, but BEST).

 

[terryforsythe]

I doubt anything would be a fair test of the box effect for those who hear "boxiness" and hype OB designs as the best (not best for some things, some rooms, but BEST).

You are never going to be able to get an apples to apples comparison, but that is the nature of the beast. What I would do is try to find a dealer that has both open baffle speakers and boxed speakers that are in the same price range, and listen to them. Hopefully, the room they are in is not terrible from an acoustics perspective.

 

[audiofooled]

People keep telling me that they like open baffle speakers because there is no "box sound", but every time I ask them what they mean, they can't tell me. And no, "other speakers sound boxy" is not an answer. I have heard answers such as "it sounds free" or "it doesn't sound constrained", etc. and then I ask them to point at a specific measurement that shows this. Nobody can do it.

I am looking for an answer that can specifically be attributed to a "box". I grant that boxed speakers have a different radiating pattern to open baffle / dipole speakers, but in that case it is better to say that you like "dipole sound" so that it is clear that it is the radiating pattern that someone is referring to. If you have an omnidirectional speaker in a box (e.g. Beolab 90), does it still sound "boxy"? Wouldn't it be better to simply say "monopole sound"?

Today, someone told me that they heard a pair of 18" open baffle subwoofers and said "it doesn't have a box sound, the bass is just there". Subwoofers are omnidirectional, so they can't have a "monopole sound". I asked him what he meant, and I didn't get a very satisfying answer.

Some have said that "box sound" might be caused by the rear wave reflecting off the enclosure and passing through the driver cone or interfering with driver movement, especially since I have heard claims that it can not be measured with a steady-state tone because somehow the cabinet reflection and driver movement are in equilibrium. That sounds like a nonsense made-up argument to me, but I am not so sure.

A more interesting argument is "low Q sound" vs. "high Q sound". Well, boxes can be tuned to different Q's. And drivers for open baffle speakers can be chosen with different Q's. I have been told that "low Q sound" sounds strained and muffled, but I don't have the experience of listening to high Q vs. low Q speakers. And: what measurement would show the effect of Q? Surely all you need to look at is the impulse/step response to see how long the driver rings for?

I am starting to think that "box sound" has no descriptive value, in the same way that "musical" is a useless term. I don't think people agree with what it means, and to the extent that boxes sound different to dipoles, it is better to specifically refer to the radiation pattern ("monopole sound") instead of "box sound". Or "high Q" vs. "low Q" sound. Am I wrong about this?

I would place a bet on air itself not being a perfect medium. Watch JJ's most recent talk and within first 10 minutes or so he points to the nonlinearities of the air itself and the physics that can't be beaten. Something he said earlier in this post:

A Broad Discussion of Speakers with Major Audio Luminaries

Just curious. I attach my version, Good evening Dr. Floyd. Alton Everest acoustics manual. and you will see that even the first room reflections are around the threshold of detection for image shift. So, don't get concerned about "image shift and focus" caused by even later room Crosstalk is...

www.audiosciencereview.com

"Most subwoofers also create audible harmonics, you really can't do much with a smaller enclosure, even with positional feedback, as far as I've seen, to prevent that. Consider, for instance, a run of the mill 15" dayton "max" sub. Put it in a 15x15x15 enclosure, and you find that the interior volume changes enough during extension and compression (way over the 120 to 140dB SPL limit for linearity in air) to make an even order distortion system. This is why a lot of the "small, powerful" subwoofers can be quickly located, which should not be the case, because of audible harmonics above 90 hz or so. Even if most of the distortion is below 90 Hz, if the phase of the harmonics lines up on the cochlea, the CNS manages to help you locate this. (note, this is not like a 'steady tone' at one frequency, which isn't going to 'locate' anything, nor is it a variation in phase across the two ears, which again is audible, but which does not appear to provide directional sensation, only spatial sensation).*

Years ago I did actually measure the pressure inside a subwoofer box of such dimensions (smallest cuboid that can fit the driver) and lo and behold, the gauge easily went +/- 4kPA within drivers excursion limits. That's roughly 166 dB in each direction, or about 172 dB absolute pressure, if you will:

I'm not even going to try and speculate on audible harmonic effects of small enclosures with bass in them, or what people would describe as "box sound", but I will say that a "crappy box" + driver interaction may sometimes affect the localization of the box itself via auditory mechanisms which are vastly complicated. But, of course, don't take my word on it only because I've heard it.

 

[Digital_Thor]

Boxy - This dwarf certainly doesn’t suffer from claustrophobia. Boxy loves the congestion of enclosed spaces and is often criticized for his lack of openness. Given the chance, Boxy would remove all letters from your system’s alphabet besides the vowels “a” “o” and “u”.

https://www.rationalacoustics.com/pages/the-7-bad-system-dwarves

 

[mhardy6647]

Perhaps the purest-ever manifestation of box sound...

source: https://www.radioshackcatalogs.com/flipbook/1969_radioshack_catalog.html pg. 38

 

[deanznz]

I liked this Box vs Electrostatic comparison by RayDunzl

and applying No Smoothing seems to tell a story.
.

 

[klettermann]

View attachment 515974View attachment 515974I guess much of the "open baffle" sound comes from the fact that there is little bass to begin with, unless your woofers are truly massive, and you boost them to hell.


>>>snip<<<

A buddy of mine listens to this:

He doesn't seem to have any bass problems. Or any other problems for that matter, except reinforcing his floor to support the 800lb equipment rack.

 

[Keith_W]

He doesn't seem to have any bass problems. Or any other problems for that matter, except reinforcing his floor to support the 800lb equipment rack.

No audible problems, or no measurable problems? If it's the latter, I would be very surprised. If it's the former, that can be easily explained away.

 

[klettermann]

No audible problems, or no measurable problems? If it's the latter, I would be very surprised. If it's the former, that can be easily explained away.

As you might guess, he's not a measurement guy. I offered to do it for him but he's not wild about the idea, LOL.

 

[Digital_Thor]

No audible problems, or no measurable problems? If it's the latter, I would be very surprised. If it's the former, that can be easily explained away.

This is one of the reasons that we can still have so many people quite happy with systems that do not measure that great - simply because we adapt so easily to something that is just "good enough". I guess, in this instance, headroom and bias plays a role too. Lots of things are impressive at first glance and try-out. But as you live with it, things become more apparent. I personally aim for longevity

 

[Phorize]

People keep telling me that they like open baffle speakers because there is no "box sound", but every time I ask them what they mean, they can't tell me. And no, "other speakers sound boxy" is not an answer. I have heard answers such as "it sounds free" or "it doesn't sound constrained", etc. and then I ask them to point at a specific measurement that shows this. Nobody can do it.

I am looking for an answer that can specifically be attributed to a "box". I grant that boxed speakers have a different radiating pattern to open baffle / dipole speakers, but in that case it is better to say that you like "dipole sound" so that it is clear that it is the radiating pattern that someone is referring to. If you have an omnidirectional speaker in a box (e.g. Beolab 90), does it still sound "boxy"? Wouldn't it be better to simply say "monopole sound"?

Today, someone told me that they heard a pair of 18" open baffle subwoofers and said "it doesn't have a box sound, the bass is just there". Subwoofers are omnidirectional, so they can't have a "monopole sound". I asked him what he meant, and I didn't get a very satisfying answer.

Some have said that "box sound" might be caused by the rear wave reflecting off the enclosure and passing through the driver cone or interfering with driver movement, especially since I have heard claims that it can not be measured with a steady-state tone because somehow the cabinet reflection and driver movement are in equilibrium. That sounds like a nonsense made-up argument to me, but I am not so sure.

A more interesting argument is "low Q sound" vs. "high Q sound". Well, boxes can be tuned to different Q's. And drivers for open baffle speakers can be chosen with different Q's. I have been told that "low Q sound" sounds strained and muffled, but I don't have the experience of listening to high Q vs. low Q speakers. And: what measurement would show the effect of Q? Surely all you need to look at is the impulse/step response to see how long the driver rings for?

I am starting to think that "box sound" has no descriptive value, in the same way that "musical" is a useless term. I don't think people agree with what it means, and to the extent that boxes sound different to dipoles, it is better to specifically refer to the radiation pattern ("monopole sound") instead of "box sound". Or "high Q" vs. "low Q" sound. Am I wrong about this?

Never heard a 'boxy' sound from a speaker but the fact that the descriptor appears to be derived of a physical characteristic of the enclosure leads me to suspect that it may be imaginary!

 

[Arindal]

He doesn't seem to have any bass problems.

If competently equalized, such open baffle line array concept with sufficient diaphragm area can absolutely work both in the bass and midrange bands.

Or any other problems for that matter,

Would be a bit concerned regarding what appears to be a ribbon tweeter, as well as the transitional band between midrange and tweeter. A lot can go wrong with such concept, and in most of cases does (not saying it is necessarily the case here, but without measurements, would say it is close to impossible to get it right).

Never heard a 'boxy' sound from a speaker

Try to listen to a bigger bookshelf or smaller tower speaker with light cabinet walls and light midwoofer diaphragm such as paper, and remove all inner damping from the enclosure prior to that. Chances are pretty good you can experience some ´boxy´ sound as a result of standing waves, resonance issues or other phenomena.

 

[ZolaIII]

It's a bit funny, they (he, who ever made that line area open buffle atrocity) tried to achieve some separation with that additional side panels on inner side. I doubt it worked, I doubt even much bigger barrier in the middle world work sufficiently enough. Tho in mono it might sound deacent (theoretically and with DSP).