Why Spinorama needs an extension to halt the race for cheap, low-quality bass with strong resonances and which Extension is best ?

[bennybbbx]

Dont trust only Spinorama, maybe on audio science can measure a example with spinorama. I find only The Meinl Mini Cajon with builtin speaker is drum simular instrument, the 70 $ version have a 2.5 inch speaker and the 160 $ version have 2 4.5 inch spiker to play playback music. It can simulate a worse designed speaker.

Here what a Cajon is. https://de.wikipedia.org/wiki/Cajón

With the klippel NFS is mean the bass Problems of the Holographic Audio calculation of the Klippel. The Cajon test is also good to compare with a freefield measure with klippel Direct Sound Calculation. Her can see that klippel seem not able to detect speaker resonances and room resonances correct, so it reduce case and bassport resonances and frequency shifts too in the measure results. https://www.avnirvana.com/threads/k...-resonances-show-with-klippel-examples.17229/

The "CTA2034 Spec-Sheet Bass Competition" – the bass equivalent of the old loudness competition(where songs heavy compressed and distorted to be louder. music platforms have stop this).
We are experiencing the exact same phenomenon, only on bass range and worse ports give more bass range that look better in CTA 2034 but they have much worser decay times and frequency shift(read about how bass ports(simular to helmholtz resonantor works) than good bass port design or closed speakers. Result was, that Closed speakers are not available anymore, because CTA 2034 did not show the advantage of a closed speaker, it show only the disadvantage of a closed speaker(the less bass)

The Spec-Sheet Bass Competition: Why CTA-2034 Fails the Time Domain

Historically, the audio industry has always found ways to hyper-optimize single metrics for marketing. Back in the day, look at the Infinity RS 6001(have no bassport but a very bad designed crossover. The price for the size was very good) https://de.scribd.com/doc/289482001/RS-6001-Technical-Sheet It was heavily hyped but sounded terrible to many ears. If anyone complained about the bloated, muddy sound, the community dismissed it "Your room is bad," or "You just need a more expensive, high-current amplifier." Back then, this marketing trick eventually failed because consumers still had plenty of honest, well-designed alternatives, and Infinity ultimately went under.

Because the modern CTA-2034 (Spinorama) standard only measures the steady-state frequency response in an anechoic(calculated) environment, it has created a massive loophole. Manufacturers are over-optimizing their speaker tuning solely for a pretty looking graph. They pump up the port output to show impressive bass extension down low, completely ignoring what happens in the real world.

The CTA-2034 measurement completely blindfolds us to two critical flaws:
1. Time-Domain Smearing: A massive ringing and overhang that persists long past 100 ms.
2. Port Chuffing: Severe turbulent airflow noise under dynamic conditions.

Today, almost every mainstream manufacturer seems to sell these "cheater ports" just to win the graph competition against rivals. Meanwhile, truly honest speakers that offer tight, precise bass—but maybe show 2 dB less output on paper—are unfairly penalized by reviewers who only stare at Spinorama charts.

The irony is that exposing these modern marketing traps is incredibly easy. Anyone with a measurement microphone can do a simple near-field measurement directly at the bass port (at a 2 to 10 mm distance). If you look at the Frequency diagram at 100 ms in REW spectrogram and compare these over-tuned speakers to a genuinely good design, the illusion of the "spec-sheet bass" can see

We need to stop evaluating bass quality by looking at static 2D lines. It’s time to look at the time domain, or we will end up(or have it) with an entire market of glorified, booming Infinity RS 6001 clones.

this also the X grok confirm .

https://rmsacoustics.nl/papers/whitepaperbassreflex.pdf

Why Bassreflex is not Suitable for
Low-Frequency Musical Sound
Reproduction

here can see that a bass port really work as a helmholtz resonator that resonate on bass port frequency at any frequency that is input.

the input signal was a 160 hz sine. output is anything else as 160 hz on the bassport. such situations happen in real music situation when play snare drum, distortion guitar mutes, or mute bass. Producer also know the problem do slightly workaround for this. they notice when make below 400 hz mono it sound better. also Vinyl do below 200 hz make signal mono. but it is not Hi fidelity. another way to avoid this worse sound, are the techno kick. the beick begin high and then slide very low so the bassport ring fit to sound. the snare drum is thin with only few level at 160-190 hz or there is no snare drum. if there need such workaround because of bad designed speaker case and bass ports, is not HIFI. ring out passport can not cancel from the woofer driver, because the woofer driver stop much earlier without so much frequency drifts as can see on the Focal alpha 65 evo. it is not a cheap speaker.
I think a near field measure 2-10 mm and show the frequency response at 150 ms can show the problems most. so can choose the speaker with the shortest decay time if you want a precise speaker
this measure was not on bass port measure, but also the thin metal backplate ring on bass port frequency. its not my room because my smaller speaker have this problem at 45 hz not. so all come together and interact thin enclosure and worse bassport. in the focal display you can see the slowness of the focal woofer. at time 0 ms it is 2 db under max level. only after 40 ms it reach the 0 db and then decay very slow. because measure is 2 mm near, room have no important influence to that

the JBL 104 have the bass Port on back. but not such bad long decay resonances in bass. but it have resonances at higher freq. frequency below 40 hz is noise because JBL 104 output at this frequency only very little so the normalisation need boost alot

 

[pierre]

The CTA-2034 measurement completely blindfolds us to two critical flaws:
1. Time-Domain Smearing: A massive ringing and overhang that persists long past 100 ms.
2. Port Chuffing: Severe turbulent airflow noise under dynamic conditions.

Hello,

on 1: a fair comparison is: can we do better with a subwoofer+a closed box+ a proper crossover? note that most people prefer the bass extension and some ringing than to have a subwoofer, more cables and setting up a crossover. I am guessing that vendors are very likely optimizing for convenience more than an obscure scientific metric that 99% of the customers have never heard about.

on 2: we have seen on ASR that a lot of ports have been optimized with FEA and do not perturb the air flow that much. KEF comes to mind. Ports are a comprise, true but they are improving.

P.

 

[girtab]

are decay differences in speakers actually audible? I would personally be more focused on the port-chuffing/distortion characteristics which does in fact lack in the CTA-2034 standard and could be very useful for filtering out speakers that run out of clean output faster than others

 

[bennybbbx]

are decay differences in speakers actually audible? I would personally be more focused on the port-chuffing/distortion characteristics which does in fact lack in the CTA-2034 standard and could be very useful for filtering out speakers that run out of clean output faster than others

most can hear that easy. play a 90 hz sine burst, or a 160 hz tone burst in REW. now hear how it sounds. you notice a decay wuum for sure when use as nearfield monitor 1 meter away. Only problem people think mostly it is room reverb. to hear that it is not the room reverb, close the bass port with socks and play the burst again. 90 hz or 160 hz is not reduce so much level with open or close bassport. it sound much tighter. But maybe not all people hear this, same was also in the loudness competion. not all hear that the loud sound sound worse. https://en.wikipedia.org/wiki/Loudness_war
have measures can help. people that not hear this can buy a cheap speaker with huge bass, but people who want a precise speaker can choose and can be sure a more expensive speaker is always better.
because speaker and room do interaction. if you have a boomy room a tight speaker let sound it better. if you have a boomy room and a boomy speaker is worse. if you have a good room then maybe a boomy speaker sound good. Harman kardon(wo buy infininty) do blind tests only in a good large cinematic room and not in near field monitoring.

think about the end of infinity and the RS6001 . because RS6001 was sell so few it get in mid of the 90 very cheap.

Amirm did show neafield measure of bass port. this is not in spinorama. here can also see some of the quality of the bass Port. when i buy focal and kali i did not know and do mistake

see the expensive focal alpha 65 evo bassport measure here
https://www.audiosciencereview.com/...cal-alpha-65-evo-review-studio-monitor.28832/
It reduce level from 45 hz to 100 hz only 3.5 db. now see cheaper HS8

Yamaha HS7 Review (studio monitor)

This is a review and detailed measurements of the Yamaha HS7 powered monitor. I purchased this last spring for testing and costs US $320 each including prime shipping on Amazon. The HS7 brings its trademark and in my opinion, attractive looks to HS7: It is a rather heavy speaker for its...

www.audiosciencereview.com

it also have 45 hz bass port resonance. at 100 hz it have 8 db reduce of bassport. this give less wrong frequency drift. the bassport should be as fast as possible reduce in frequency i learn from my measures. more expensive speakers as neumann or genelec have also slower frequency reduce.

but to see all, such a bass port frequency diagram should also do at 100 ms or 150ms . and as faster the woofer stop, and start the more the punch feeling get from music with same level. also it is better for health when a kickdrum or snare is 2 cycles long instead of 4 cycles of a slow speaker.

this are small case have no bass port https://www.audiosciencereview.com/...ds/avantone-pro-mixcube-monitor-review.42817/ and only can see huge disadvantage in bass, but not that it is faster in bass because have no bassport.

when have 100 ms time slice of woofer can see this too

 

[girtab]

close the bass port with socks and play the burst again.

I actually use my nearfield kanto yu2 with their ports stuffed with foam because their ports chuffed at times, however i did not notice any difference in the time domain just a reduction in overall bass (which i could counter act with EQ because the port wasnt chuffing anymore). Maybe its just me though.

 

[R4pture]

but to see all, such a bass port frequency diagram should also do at 100 ms or 150ms . and as faster the woofer stop, and start the more the punch feeling get from music with same level. also it is better for health when a kickdrum or snare is 2 cycles long instead of 4 cycles of a slow speaker.

My apologies if I write nonsense, but does port resonance decay really matter in real world scenarios? Take a typical domestic room, normally furnished (my reference are households in germany, plastered walls, essentially no insulation, "Altbau"). You will probably measure decay times exceeding a full second at certain frequencies. Lots of energy is reflected back into the room causing all sorts of chaos including very high decay times. From my own observations, improving room acoustics or implementing DSP impacts the bass tactility in a much higher degree than just closing the port of a speaker. Maybe that is different in an already great sounding room. Never been in one of those unfortunately (or maybe fortunately).

almost every mainstream manufacturer seems to sell these "cheater ports" just to win the graph competition against rivals. Meanwhile, truly honest speakers that offer tight, precise bass—but maybe show 2 dB less output on paper—are unfairly penalized by reviewers who only stare at Spinorama charts

A well designed port should drastically extend the lower frequency output at the cost of a much faster roll-off, higher distortion and additional junk potentially bleeding out of the port. A couple years ago I tested the physical impact of my subwoofer with open and closed port. Same EQ, same position. The tighter bass I felt from closing the port was essentially just "less" bass overall, a shift of the roll-off point towards higher bass frequencies which slightly reduced the impact of my lowest measured mode. Someone can prefer that, but I think it simply hides the problem. Put a different speaker into the same room with greater bass extension and the problem comes back. I had to re EQ the subwoofer with much higher low frequency boost to gain back what I wanted to feel. I started to hear my subwoofer bottoming out at high dynamic moments, so I reopened the port and never had this problem again. Yes, you add potential for distortions like port turbulence. Port turbulence in specific is a problem, but it has SPL dependencies. I don't know about the pure CTA-2034 definitions, but I always though port turbulence was covered in distortion tests as "added distortion for the final measurement result".

play a 90 hz sine burst, or a 160 hz tone burst in REW. now hear how it sounds. you notice a decay wuum for sure when use as nearfield monitor 1 meter away. Only problem people think mostly it is room reverb. to hear that it is not the room reverb, close the bass port with socks and play the burst again.

Maybe you are right, but sitting close to the speaker will not remove the rooms impact. The bass you hear @1 meter distance to the speaker is already infested by your room acoustics, less so at higher frequencies. The position of the port also matters because it couples differently with the room. Best way to test what you described is by removing the room entirely -> put the speakers outside. I wonder if that typical "wuum" is still audible @1 meter distance. Again, you may be right. After all, it is speaker dependent.

Personally, with all the tech I have in my hands right now and the knowledge how much impact my own room have for bass tactility compared to my ported subwoofers, I would say I prefer speakers with "cheater ports" to add more output at lower frequencies to then use this additional output in combination with MIMO based room-correction systems like Dirac ART to tackle obvious room decay issues.

 

[bennybbbx]

My apologies if I write nonsense, but does port resonance decay really matter in real world scenarios? Take a typical domestic room, normally furnished (my reference are households in germany, plastered walls, essentially no insulation, "Altbau"). You will probably measure decay times exceeding a full second at certain frequencies.

The fundamental problem with a lazy bass reflex port is a dynamic phenomenon called "Frequency Drift" or "Energy Storage". When a quick, percussive transient (like an E-guitar palm-mute or a kickdrum, Snare drum , or other percussive instrument) stops, a bad port keeps ringing out and instantly shifts the pitch down to its own native tuning frequency (as proven by the 44 Hz oscilloscope shot above).

If you put this speaker into a room with long reverberation times or a strong room mode at exactly that dropped frequency, you create a destructive acoustic chain reaction: The speaker itself generates a künstlich shifted "ghost frequency" that wasn't even in the music, and the room then amplifies and prolongs this wrong frequency for over a second.

Our hearing and brain can compensate for a lot of room reflections and flaws, but everyone has a threshold where the bucket overflows. Eventually, "ear fatigue" sets in, the music loses clarity, and you simply want to stop listening. This is why even small improvements can have a huge impact. It's exactly why people report massive benefits from just installing a few targeted bass traps or basic acoustic treatment, rather than completely deadening the entire room.

A bad room cannot mask a lazy speaker; it acts as a megaphone for the speaker's time-domain flaws. For deep insights into how a ported system acts as a slow energy storage filter compared to a tight sealed cabinet, check out the [Grimm Audio Whitepaper on Bass Reflex Limitations](https://grimmaudio.com).

I ask AI for audio science very often. but problem is, most science is in books i do not own so can not verify it. maybe somebody have that book can read on page 12 thru 18 this ? . I trust AI not, i use it only for search specific neutral way and i ask always for online links so i can verify myself. in this situation it found only book.

2. Dr. Sean Olive (Audibility of Low-Frequency Resonances) The original link to the paper: Audio Engineering Society (AES) - Sean Olive et al. The exact text and page references: The paper has the AES number Preprint 4432. The key psychoacoustic test results regarding the perception of high-Q bass resonances can be found on pages 12 through 18. What it says there: Olive demonstrates through blind tests that the human brain extremely quickly identifies narrowband resonances (specifically, the uncontrolled oscillation and ringing of a bass reflex port at its tuning frequency) in the deep bass as a disturbing coloration. He shows that these temporal errors place a massive strain on the ear and lead to the dreaded ear fatigue much more quickly than a slightly nonlinear frequency response.

I have attach such burst. you can test yourself if you hear or not. The ring out get strange feeling in ear. happen not when port is closed or headphone. you can compare.

if you test yourself in REW the frequency of tone must fit to sample rate so start and stop end exact at 0 and you can use rectangle Filter= no Filter.

====================================================================
REW GENERATOR RASTER (Samplerate: 48.000 Hz / 48 kHz)
====================================================================
Gewünschte Anzahl Samples Passt in REW Physik-Status /
Frequenz(Hz) pro 1 Cycle (0.5Hz Schritt) Test-Anwendung
--------------------------------------------------------------------
40.0 Hz 1200 Samples JA (glatt) Tiefster Subbass-Test
48.0 Hz 1000 Samples JA (glatt) Nahe an Focal-Resonanz
50.0 Hz 960 Samples JA (glatt) Perfekt für ESI-Check
60.0 Hz 800 Samples JA (glatt) Klassischer Kick-Punch
75.0 Hz 640 Samples JA (glatt) Nahe an JBL-Tuning
80.0 Hz 600 Samples JA (glatt) Oberbass-Punch
96.0 Hz 500 Samples JA (glatt)
120.0 Hz 400 Samples JA (glatt) Kickdrum-Oberton
150.0 Hz 320 Samples JA (glatt) Kritischer Grundton
160.0 Hz 300 Samples JA (glatt) Snare-Punch-Bereich
200.0 Hz 240 Samples JA (glatt) E-Gitarren-Mute-Kern
240.0 Hz 200 Samples JA (glatt) Absolut sauberer Teiler
300.0 Hz 160 Samples JA (glatt) Höchste Port-Grenze
400.0 Hz 120 Samples JA (glatt) Unterer Mittelton
480.0 Hz 100 Samples JA (glatt) Extrem sauberer Teiler
600.0 Hz 80 Samples JA (glatt) Mittlere Frequenzen
800.0 Hz 60 Samples JA (glatt) Übergang zum Hochtöner
960.0 Hz 50 Samples JA (glatt) Exakter Teiler
1200.0 Hz 40 Samples JA (glatt) Hochton-Testgrenze
2400.0 Hz 20 Samples JA (glatt) 1-Cycle-Hochton-Trick
4800.0 Hz 10 Samples JA (glatt) Perfektes Sample-Raster
====================================================================
I do that at 80 hz , 96 , 120, 160 ,200 hz. all sound much better when bass port is closed or headphone.

and also must say it is a matter of taste. at whats best . but the measure results help to decde. many notice that a speaker good in spinorama they think sound muddy and worse. so bass port problems can be the reason

are decay differences in speakers actually audible? I would personally be more focused on the port-chuffing/distortion characteristics which does in fact lack in the CTA-2034 standard and could be very useful for filtering out speakers that run out of clean output faster than others

Read also above part. The port chuffing can only measure with microphone a klippel have(it is specified to work upto 140 db) my beyerdynamic MM1 only upto 115 db. because when measure nearfield and speaker is at 96 db it is much louder for microphone. I do my measures when i have set volume of speakers very silent so microphone level REW show is 90 db. when make louder bass port go even more worse. AI tell that Klippel filter the bassport measure alot, but on a unfiltert measure can see high distortion and FR changes.

here is table AI tell about db for microphone. gor klippel is 10mm measure no problem at 86 db speaker volume at 1 meter
Distance 30 mm: The microphone must be able to handle approximately 108 dB to 112 dB SPL. (Your microphone, which can handle up to 115 dB, can just barely manage this without clipping).
Distance 20 mm: The sound pressure level rises to approximately 114 dB to 118 dB SPL. (Here, your microphone is already teetering on the edge of total overload.)
Distance 10 mm: Right in front of the cardboard or inside the port slot, the level hits a brutal 120 dB to 126 dB SPL!

at 96 db speaker volume 1 meter. not translate, but you see distances to db. also measure need a little on side of bass port because the air of bassport should not flow direct in microphone. klippel can handle this, or need very expensive microphones

• Bei 30 mm (3 cm) Abstand: Das Mikrofon muss brutale ca. 124 bis 126 dB SPL verkraften! (Hier würde dein 115-dB-Mikrofon bereits ohrenbetäubend clippen und nur noch eine Rechteckwelle anzeigen).
• Bei 20 mm (2 cm) Abstand: Der Schalldruck steigt auf unvorstellbare ca. 128 bis 130 dB SPL.
• Bei 10 mm (1 cm) Abstand: Direkt an der Port-Kante oder vor der Membran schlägt der Pegel mit mörderischen ca. 134 bis 136 dB SPL ein

maybe for first enhance step of spinorama there should do at chuffing measures results. bad designed ports do lots of chuffing.

Google AI
When Klippel measures the port, the results are often mathematically normalized. This means that while you can see the port’s frequency response on their mathematical graphs, you don’t see the dynamic panting and compression of the air at real-world listening volumes!

The port collapses: This is known as port compression. This is exactly the effect you don’t see at all in Spinorama. At 96 dB, the port is literally clogged by massive air turbulence. The tube acts like a solid wall to the sound. The level loss: Even though you’ve turned up the speaker by 6 dB, the port may only deliver 2 to 3 dB more level at its tuning frequency (e.g., 74 Hz or 80 Hz). It compresses. The result in the REW distortion diagram: If you position the microphone at a 45-degree angle just next to the port to avoid clipping, you’ll see at 96 dB that the distortion factors (K2 and, above all, the inharmonic flow noise K3/K5) reach epic heights in the bass range (often 10% to 30% THD!). At this level, the tube no longer functions as a clean resonator, but rather as a full-fledged noise and distortion generator.

 

[voodooless]

most can hear that easy. play a 90 hz sine burst, or a 160 hz tone burst in REW. now hear how it sounds. you notice a decay wuum for sure when use as nearfield monitor 1 meter away. Only problem people think mostly it is room reverb. to hear that it is not the room reverb, close the bass port with socks and play the burst again.

Well, sure, it's different: the frequency response changes. If you want to compare apples to apples, then the frequency response needs to match.

 

[bennybbbx]

Well, sure, it's different: the frequency response changes. If you want to compare apples to apples, then the frequency response needs to match.

this test use only 1 frequency. and the frequency often so high that the bassport did not output much at this frequency. so when close the bassport change not much the frequency level at 120 hz. maybe on 96 hz and 80 hz more. all additional what you can hear are fake frequency signals from bassport or case resonances. you also can play sine tone for example when you play a continues sine at 80 hz. set the volume to same level(measure with a db levelmeter) so that 80 hz have same volume with open and close port. a db level meter is cheap and is a good investment for ear health. so you can see if you hear too loud or it is ok. you can find in internet online sinegenerator for test signals or wav

 

[voodooless]

this test use only 1 frequency. and the frequency often so high that the bassport did not output much at this frequency. so when close the bassport change not much the frequency level at 120 hz. maybe on 96 hz and 80 hz more. all additional what you can hear are fake frequency signals from bassport or case resonances. you also can play sine tone for example when you play a continues sine at 80 hz. set the volume to same level(measure with a db levelmeter) so that 80 hz have same volume with open and close port. a db level meter is cheap and is a good investment for ear health. so you can see if you hear too loud or it is ok. you can find in internet online sinegenerator for test signals or wav

Yes, that works. The level matching is the important bit here!

But I'm very sure that a lot of what you hear when you play music, not single tones, is in fact the frequency response differences, unless we're looking at severe design abominations, of which I'm sure there are plenty to go around. Scuffing, resonances, and post noises are real things, as are the longer decay times. Sometimes audible, sometimes not. For sure, it's good to measure.

Spinorama alone does not cover these, obviously, because it only looks at the on- and off-axis frequency response of a speaker. It was never claimed that a spinorama fully defines a speaker's performance.

But Amir's test already covers some of these things, albeit indirectly. Port resonances usually show up when the individual drivers are measured; frequency response gives a good indication of what kind of tuning is applied; and distortion is also a fairly good indicator of bass performance. Not perfect by any means, but good enough in many cases.

 

[bennybbbx]

But Amir's test already covers some of these things, albeit indirectly. Port resonances usually show up when the individual drivers are measured; frequency response gives a good indication of what kind of tuning is applied; and distortion is also a fairly good indicator of bass performance. Not perfect by any means, but good enough in many cases.

the measurements on ASR show only the frequency response at 0 ms and ignore time. see the anim gif i upload at 0 ms the focal alpha have 2 db less at 45 hz at 0 ms. it reach only at 40 ms maximum peak 0 db normalized in this measure and ring out very slow. see the worse energy peak level of the focal in compare to the JBL. the energy peak time in REW spectrogram work also good on hear position, does not jump so much as group delay.

Klippel Page (AI find) did write this https://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Loudspeaker regular signal distortion caused by design_part 1_Klippel_Werner.pdf

Spectral components below 100 Hz contribute to the excitation level of one critical
band

Phase distortion corresponding with a group
delay variation of 0.4 …2 ms within a critical band change the timbre and roughness
of the sound

Precedence effect [5] maintains the primary image as long as the lateral reflections
are sufficient low or the time delay is small,  strong reflections after 80 ms are
unpleasant and are perceived as echo

developers that build expensive speakers can be happy, when there speakers are good in such test. I and i think much more that think sound can be better try out expensive speaker with good measure results. but currently there is no reason see in spinorama wy buy a speaker that cost more than 300 $. you never can be sure that it is very worse in group delay time which show only when the energy peak happen and not how fast or slow they produce rumble

Magnepan LRS+ Speaker Review

Magnepan LRS+ Review

www.erinsaudiocorner.com

KEF Q11 Meta Speaker Review

KEF Q11 Meta Review

www.erinsaudiocorner.com

See the Erin measures. this over 1000 $ speaker look very worse in group delay even if klippel tend to reduce case resonances due to holographie calc smoothing in bass.
what the reason to buy such expensive speakers if timing not matters.

you can do a easy examples play a song 1 minute linear, then reduce the treble and play 1 minute . now change to linear and the song sound as if it is too bright. so you can see, brain can more easy do frequency correction and thats the reason that headphones sound great also when it have not such a good frequency.

because Klippel say the time 80 ms, then maybe show the FR at 80 ms. here is a table of the times how much this frequencies are reduce at 140 ms of my speakers.
maybe i should better show time at 80 ms

EDIT: some more speakers. the as good test Neumann KH80 but very worse group delay at 60 hz 21 ms https://www.erinsaudiocorner.com/loudspeakers/neumann_kh80/
the https://www.erinsaudiocorner.com/loudspeakers/yamaha_ns10m_studio/ old NS 10 weak on bass but many that hear it like the clarity and it was studio reference. groupdelay at 60 hz 7 ms instead of 21 ms the KH 80 have

 

[bennybbbx]

I try to find port chuff in measures, but because REW measure software show only the distortion of harmonics it is not show. AI tell the Klippel „Rub & Buzz“-Modul should show chuff noise

i play a 58 hz sine and i hear the port noise . the speaker reach at 1 meter distance 84 db. i put the measure microphone 4 cm near bass port outside so the air reach not microphone. i get at microphone level of 102 db so it is on safe side for the microfone. but when look at the distortion levels look nice in RTA . thats anothe reason wy i do not trust measure software on scope can see that port noise. the output signal do lots jitter around the 58 hz.

the only thing can see that at 400-500 hz much group delay changes happen. it is no measure problem. normaly when measure speaker only low bass (<40 hz)do lots jump in group delay and never over 300 hz. so group delay maybe indicate chuff noise. I measure 2 volumes 66 db and 84 db at 1 meter distance measure. you can see the woofer measure also 4 cm away look very good at 300-500 hz

I always show the truth and i upload my measures, so you can look on all other values yourself. this 3 measure fit in ASR forum it have zip 1.7 megabytes. how much mb can max upload at ASR forum in zip ?