How audible are resonances, or how much do they matter?

[bachatero]

A few years ago I bought some EV ZLX-12BT speakers which are popular with concerts and other "live sound" applications.

However, they only just sound fine. There's something I just can't put my finger on. This is the frequency response:

It's not bad! The other specs are also a strong showing with a real DSP built in and a huge amplifier.

This still doesn't explain why they only sound fine though. Then I realized that they're made of plastic which is resonance city. Here's the frequency/impedance response of the base, passive speaker without DSP:

There are lots of resonances as indicated by the bumps in FR and IR. Most of them are between 100 and 300Hz.

Could this be why these speakers only sound fine? In other words, can resonances be audible enough to matter or they just pretty lines on a chart/waterfall? If so, that would explain why many higher end speakers go for wood if not for "premium" appeal.

 

[Redacted]

You don't tell us whether the plots are measured in your actual room or are "theoretical plots" from the manufacturer - which means I'm not sure what you mean by "resonances".

In any room, you are subject to reflections from surfaces, and depending on the topology and furnishing* of the room, and your specific listening position, these can anything from "terrible" to "no problem, especially for bass (but treble can also "jangle", which is a technical term for those who know) You may want to read the vast amount of discussion on EQ'ing on ASR.

*risking being flamed, especially by ladies,, I have always found that listening rooms furnished by women are vastly superior to the kind of minimalistic or spartan rooms favoured by some men (me included). It's like having "room treatment included in the deal."

Also, I'm not clear on "live mode, club mode" etc - it sounds hokey to me! I like to hear "as recorded, where possible". And you seem to lack low bass.

 

[multichannel_guy]

There are bad EVs and good EVs.
You can't cheap out too much with the plastic sht in pro audio.
Here's a good EV, not very cheap, but, with no audiophile markup. You just pay for the parts quality and sound. Get the H-V coverage suitable for your room and taste.

EVF-D 12 | Electro-Voice

products.electrovoice.com

 

[bachatero]

There are bad EVs and good EVs.
You can't cheap out too much with the plastic sht in pro audio.

I already secured some Yamaha DZRs from the last batch until 2027, which are made of wood instead of plastic.

You don't tell us whether the plots are measured in your actual room or are "theoretical plots" from the manufacturer - which means I'm not sure what you means by "resonances".

There's also no reflections or "room" here since my main applications are outdoor group bachata dances and something else similar to that.

All I (and probably others here!) want to know is, generally, can speaker resonances be audible enough to make one sound worse than a speaker without them? The PA speaker example here is merely an example.

 

[Curvature]

You don't tell us whether the plots are measured in your actual room or are "theoretical plots" from the manufacturer - which means I'm not sure what you mean by "resonances".

Strong resonances are wrinkles in the impedance plot, like 250Hz and 1300Hz, which are likely to show up at all angles and make themselves apparent.

@bachatero Remember that you are looking at a single on-axis curve (and we don't know what the off-axis response will show.

Apart from that, resonance audibility depends on Q (shape, whether narrow or wide) and level. Think of them as a kind of parametric EQ filter.

 

[Curvature]

Measurements for speaker EV EVC-1122

www.spinorama.org

These EVs certainly don't look good, for comparison.

 

[Redacted]

Strong resonances are wrinkles in the impedance plot, like 250Hz and 1300Hz, which are likely to show up at all angles and make themselves apparent.

@bachatero Remember that you are looking at a single on-axis curve (and we don't know what the off-axis response will show.

Apart from that, resonance audibility depends on Q (shape, whether narrow or wide) and level. Think of them as a kind of parametric EQ filter.

I was asking if the user believes it's some kind of inherent resonances in the speaker cab, or some other woo-woo... I am well versed with how speakers seem to work, and all the terminology, thanks!

It's probably best to do the research whenever any of the words "pro"; "studio"; "live mode" or even "audiophile" (and many more) are being pushed out by manufacturers.

 

[kemmler3D]

As far as I know, resonances are considered one of the worst and most audible speaker flaws. The impedance plot and FR seems to show a pretty big one at 220hz, I could imagine that being audible for sure. Also looks like a bad one just past 1Khz.

Also based on the first plot, it looks like maybe they are compensating for beaming past 4Khz by having a rising response. This would tend to make the treble sound not quite right.

If you look at the comaprison between the passive and active plots, you also see a big bass boost (~10dB) which is likely to cause a good bit of distortion.

Overall I don't see a shortage of reasons this speaker might sound "just okay" in practice.

 

[HalSF]

Floyd Toole’s primer on resonances near the beginning of Sound Reproduction (4th edition) is pretty cool.

1.5.1 Resonances Are Important

Almost all of the sounds we are interested in are composed of collections of resonances. Voices and musical instrument sounds are combinations of mechanical resonances (vibrating vocal cords, strings and wooden panels connected to them, vibrating reeds or lips in a horn mouthpiece, skins of drums, etc.) and acoustical resonances (mouth and nasal cavities, resonances in the complex cavities within stringed instruments, resonances in the tubes of brasses and woodwinds, pipes of organs, etc.). To these are added scraping, clicking and aerodynamic/breathing sounds, all of which add up to distinctive, highly recognizable timbres of the sound generated by people and instruments. If loudspeakers add resonances when reproducing such sounds, they modify the timbre, which listeners might recognize. The problem is especially annoying because resonances in loudspeakers modify the timbre of all sounds played through them in the same way, adding a repetitious component to what is heard. This is why they are easily detected in comparison listening tests. In real life, we can adapt to a certain amount of this. We all have enjoyed music and movies through inferior loudspeakers, but when presented with a comparison to more neutral reproduction, the unwanted resonances stand out and are judged negatively. In other words, we can live with less than perfect sound, but if given the choice, we prefer neutral, non-resonant reproduction. In terms of identifying useful loudspeaker measurements, those that permit the recognition and evaluation of resonances are the most valuable. A single curve is not sufcient. This will be explained.
Mechanical and acoustical resonances can arise in the transducers, and in the enclosures of loudspeaker systems. Much ado has been made about mechanical resonances in loudspeaker enclosures, for good reason. They are large surfaces and can radiate signifcant sound if they move. When loudspeakers are measured in an anechoic chamber, or equivalent, and examined through 360° of rotation, any such radiated sound is captured, and, if signifcant, its presence will be noted. However, accelerometer measurements of the mechanical movement at a point on an enclosure surface is not defnitive evidence of efectively radiated sound energy, or of its audibility. Some resonant modes in panels exhibit similar areas simultaneously moving in opposite directions. There is movement, but little sound is radiated. With scanning laser interferometers, it is possible to anticipate the sound radiating modes and provide selective stifening or damping to address the problems. Brute force methods, like massively thick, heavy materials also work, of course, but elegant engineering can be efective and keeps cost and weight down.
On one of my visits to Japan, my attention was drawn to a popular brand that had an inch of concrete poured into the top of every loudspeaker. This was so that it would pass the “knuckle test” exercised by shoppers as they moved around the store foor tapping the loudspeakers. That was clever, but the knuckle test itself is not. It excites the panel at the point of contact, not as it is by sound inside the cabinet, which is pressure distributed over the surface. A well-designed loudspeaker might not pass the knuckle test. More folklore.

 

[fpitas]

you seem to lack low bass.

Probably high-passed for live sound. The alternative is often a destroyed woofer.

 

[Redacted]

Live sound? Not the kind of gig/pub/home jam I've been to if so little bass!

 

[bachatero]

Probably high-passed for live sound. The alternative is often a destroyed woofer.

The DZRs compensate for this by borrowing a feature from consumer speakers, multi band compression. In other words, you can get more bass at lower SPLs with the catch that at higher SPLs it ducks. Here's what the final product looks like:

I think it's worth having even if it turns not-flat at high volumes because those high volumes are absurdly loud and probably only exist in true concert level situations.

Live sound? Not the kind of gig/pub/home jam I've been to if so little bass!

You probably heard the subs which can get to absurdly high powers (like 10s of kWs)

As far as I know, resonances are considered one of the worst and most audible speaker flaws.

Floyd Toole’s primer on resonances near the beginning of Sound Reproduction (4th edition) is pretty cool.

1.5.1 Resonances Are Important

Seems like despite being audible resonances receive far less attention than FR and distortion. Curious!

It's probably best to do the research whenever any of the words "pro"; "studio"; "live mode" or even "audiophile" (and many more) are being pushed out by manufacturers.

The truly pro speakers like the DZRs and also the high end EVs aren't immune to this either because the DZR lineup has the "FOH/Main" bass boost setting and the pro EVs have a same "Music, Live, Speech, Club" settings too.

So, going from here, I wish there was more emphasis on resonances and good quality materials because they obviously make so much of a difference. As Toole said even enclosures that don't pass the knuckle test can perform well so even that isn't a perfect indicator.

 

[kemmler3D]

Seems like despite being audible resonances receive far less attention than FR and distortion. Curious!

FR and distortion are things that are somewhat within the user's control via EQ, adding subs, etc. Resonances are baked into the speaker's design. There is no real solution to resonances except 1) open up the speaker and add bracing / stuffing or 2) don't buy that speaker.

Most people on ASR will have bought mostly resonance-free speakers in the first place, so it's not discussed as much here, but it comes up a lot on DIYAudio as people are talking about designing and building speakers there. A ton of discussion on cabinet materials, bracing and how to deal with cabinet resonances there.

In that context distortion is mostly dealt with via driver selection at the very beginning of the process.

 

[john61ct]

If you look at the comaprison

my new favorite word

Coming soon to a dystopia near you...

 

[AJM1981]

Once i had somekind of weird resonances in a loudspeaker when the lower frequencies produced by the right channel loudspeaker's woofer somehow got fed back from the frame of a baker's trolley to the woofer. I really thought it was a defect.

 

[Redacted]

Just don't buy crappy speakers!
I could regale everyone with tales of scissors that did not cut paper very well, if that might be more interesting

 

[MAB]

Seems like despite being audible resonances receive far less attention than FR and distortion. Curious!

I'm not sure what you are missing, resonances are called out repeatedly, and discussed at length. For example a recent review calls out resonances repeatedly:

HSU CCB-8 Speaker Review

This is a review and detailed measurements of the HSU CCB-8 "constant directivity horn" speaker aimed at home theater market. It was kindly drop shipped by a member and costs US $389 each. I kind of like the subwoofer styled, chunky enclosure. Back side shows dual ports which came partially...

www.audiosciencereview.com

The reviews where he doesn't call out resonances seem to be for speakers that don't have noticeable resonant behavior. The fact that resonances also interfere with Frequency Response is also discussed at length. There are also endless threads on absorbers and fancy feet, which kind of adopt the goal of low speaker resonances to accessories, which can get interesting since there is limited means to fix speaker resonances with an accessory.

Yes, there is sometimes an oversimplification to a single metric like SINAD, FR, etc. But that isn't what is being offered in the reviews and much of the discussion.

 

[RickS]

Dr. Toole has been very clear about the negative impact of resonances both from the speaker and the room. As I looked into it, some of the content has been buried so this thread will hopefully serve to highlight his findings for the OP and others.

I would suggest starting here:

Dr. Toole's 4th Edition Book is Coming! (Discount)

Your wife's suggestion would cause you to miss a bunch of useful stuff:(. Sorry about the problem. Only the publisher can help. Go to Routledge.com, scroll down to the very bottom - the dark blue area - and click on customer service. Good luck. Good news, I followed the same steps on my PC...

www.audiosciencereview.com

More content can be readily found by using the forum search engine.

 

[bachatero]

Overall I don't see a shortage of reasons this speaker might sound "just okay" in practice.

Curious about something here. The last stand for my two EV ZLX speakers before the Yamahas take over will be a 50 person bachata dance on top of a parking garage. Right now, they're using some JBL Partybox 310 and it's fine, but only fine. Do you think a stereo ZLX setup here will outperform the Partybox despite having less bass extension?

 

[bachatero]

I would suggest starting here:

Dr. Toole's 4th Edition Book is Coming! (Discount)

Your wife's suggestion would cause you to miss a bunch of useful stuff:(. Sorry about the problem. Only the publisher can help. Go to Routledge.com, scroll down to the very bottom - the dark blue area - and click on customer service. Good luck. Good news, I followed the same steps on my PC...

www.audiosciencereview.com

I've heard a lot about Dr. Toole's textbook. One of my optics professors (Bahaa Saleh) has the equivalent for photonics and I hear it's an authoritative source as well.