Car Audio Explained, Part 18: Recordings, Listening and Who Andy Wehmeyer Is (Andy Wehmeyer's Lessons)
This is Part 18 of 19 in the series Andy Wehmeyer on Car Audio, Explained for Beginners. Start here · Download the full guide as a PDF
Unofficial guide. Andy Wehmeyer's points are paraphrased from his public forum posts, blog, tuning guides, videos and podcasts, with a link to each source; the plain-English explanations were written for this guide. Not written, reviewed or endorsed by Andy Wehmeyer or Audiofrog.
5.7 Recordings, listening and hearing
What this part is about: How records are actually made, what a well-tuned car should sound like, and how to listen to and judge a system. It also covers how our hearing works and where it falls short, including age, head movement and the tools people use to measure sound.
5.7 #1 · Recordings are constructed fiction; aim for "believability", not "accuracy".
Most records are assembled from parts recorded on different days ("a deep fake" of an event); early reflections are how our ears confirm what our eyes see. Sources: CMA 2023 @35:05 · OFCAP 19 @3:28:03 · OFCAP 38 @39:05
In plain English: Many people judge a system by how "accurately" it reproduces a recording. He says audiophiles tend to assume every recording places the listener in the audience, facing a stage. His point is that most records never were one real performance. The musicians are often recorded separately, on different days, and the parts are put together afterwards. He calls the result "a deep fake" of an event, so there is no single original moment to be accurate to. Instead he aims for believability: the sound should convince you of where the players are and what the space around them sounds like. Early reflections are the first echoes of a sound bouncing off nearby surfaces, arriving a split second after the sound itself. He says these are how our ears confirm what our eyes see, which he notes is why audiophiles close their eyes when they listen.
5.7 #2 · The goal is a pleasing room, not no room.
Stereo in an anechoic chamber sounded horrible to him; music is written for performance spaces (he recommends David Byrne's How Music Works), a car is too small and reflective to be reverberant, and a car can at best suggest a space larger than itself, even by adding a virtual room. [RARE] Sources: DIYMA 2017-07-05 · DIYMA 2017-07-04 · CMA 2023 @33:01
In plain English: An anechoic chamber is a special room lined with sound-absorbing material, so nothing bounces back: no echoes, no room sound at all. Many people believe the ideal is to get rid of the car's reflections so you hear only the speakers. He says he has heard a stereo pair in an anechoic chamber, and it sounded horrible. His point is that the room is part of the music. Music is written for the space it is played in; his examples are rock for clubs, and choral or baroque music for churches. So the aim is a pleasing room, the way concert halls are designed, not no room. "Reverberant" describes a space where sound keeps bouncing around and slowly dies away, like a church or a concert hall. He says a car is too small and reflective for that. Even with a virtual (electronically created) room added by a processor, the most a car can do is suggest a space bigger than itself.
5.7 #3 · What a stereo that "works" sounds like.
Instruments spread across the dash as panned, vocals centred, room and depth if recorded, true timbre, and speakers that "disappear"; that moment isn't magic, it happens whenever a car is tuned correctly. Stereo was built for one centred listener. Sources: OFCAP 19 @1:51:00 · B2 @39:51
In plain English: This is his description of the result you are aiming for. "Panned" means the mixing engineer placed each instrument somewhere between the left and right speakers. When the system works, you hear the instruments laid out across the dashboard where the engineer put them, with a centre-mixed singer in the middle. If the recording captured a room and depth, you hear those too. "Timbre" is the character of a sound, what makes a bassoon sound like a bassoon. And you stop hearing the speakers as the sources of the sound: they "disappear". Many people treat that moment as rare magic, reached only by ever more precise tuning. He says he gets it every time a car is tuned correctly. He also reminds us that stereo was designed for one listener sitting in the centre, between the two speakers. In a car you can't sit in the middle, which is why a car needs extra tuning steps to get there.
5.7 #4 · Images can only land where the mix and the speakers allow.
Engineers place sources mostly by level (about 6 dB moves an image halfway to one side); a sound from one speaker comes from that speaker, side reflections can't widen a stage beyond the car, and panning the balance fully left shows your stage's true edge. [RARE] Sources: EDUCAR · DIYMA 2017-08-21 · DIYMA 2017-08-18
In plain English: An "image" is the spot a sound seems to come from, even when there is no speaker there, like a singer who seems to stand in the middle of the dash. A dB (decibel) is the unit for differences in loudness. His point is that recording engineers mostly place sounds left or right by making them louder in one channel than the other. By his rule of thumb, about 6 dB more in one channel moves the image roughly halfway from the centre to that side. It follows that a sound played by only one speaker comes from that speaker. His thought experiment: put two speakers in the middle of a football field, with nothing for sound to bounce off, and turn the balance fully left; the sound comes from the left speaker. Many people believe reflections off the car's sides can make the stage wider than the car. He says they can't. So in practice: once the delays are set and left and right are matched, turn the balance fully left, then fully right. That shows the true edges of your stage.
5.7 #5 · The first reference a tuner needs is two speakers in phase, not a concert.
In plain English: Many people believe a tuner's most important reference is knowing what live music sounds like, so they should go to concerts. He agrees a reference helps, but says the first thing to learn is simpler: what two speakers sound like in phase versus out of phase. "In phase" means both speakers move in and out together. "Polarity" is which way round a speaker is wired; flipping one makes it move opposite to the other, and many tuners have never heard that difference. His exercise: buy any working, matching pair of speakers at a thrift store for about $5. They "do not have to be great", only the same. Set them up so the two speakers and your seat form a triangle with equal sides, sit exactly in the middle and play music. You will hear sound appear between the speakers. His point is that imaging isn't magic; it is simply what two similar speakers do for a listener in the centre.
5.7 #6 · How experienced listeners judge a car in seconds, and why multichannel differs.
In plain English: He lists what experienced listeners check first when they sit in a demo car. Is the bass full and impactful, and does it seem to come from the front? Is the singer in the centre? Does the stage have width and depth? He notes that width and depth are partly properties of the recording itself. "Two-channel" means ordinary stereo: just a left and a right signal. "Multichannel" means more channels, for example extra speakers at the sides or rear fed by a processor. A diorama is a small model scene in a box. His point is that even perfect two-channel sound is like a little scene laid out on the dashboard. Multichannel can sound like a space bigger than the car, and it can do that for two people at once, not only the driver.
5.7 #7 · A correctly tuned car makes poor recordings sound better, not worse.
He rejects the idea that accuracy "exposes" bad recordings; that belief is why ear-only tuning goes wrong. [RARE] Source: DIYMA 2016-01-28
In plain English: Many people believe a very accurate system is unforgiving: it "exposes" every flaw, so poor recordings sound worse on it. He rejects that. Once a car is tuned correctly, he says, recordings he once thought were terrible on lesser systems often sound more interesting and detailed. "Ear-only tuning" means adjusting a system purely by listening, without measuring. His point is that the "accuracy exposes bad recordings" belief is exactly why tuning by ear alone goes wrong. He doubts that someone tuning by ear in their backyard is really exposing faults in recordings made by professionals.
5.7 #8 · Verify with tracks whose placement you know.
Favourite music can mislead (a vocal may never have been mixed centre); Audiofrog's CD uses band-limited mono noise, instruments at five positions, a voice in two rooms and EDM to check that impact comes from the front. Sources: UMI-1 video @27:01 · OFCAP 19 @2:05:01
In plain English: When you check a tune, you need to know where each sound is supposed to be. His warning is that your favourite song may not tell you. Its singer may never have been mixed in the centre, and you could end up tuning the system to put them there. That is why Audiofrog (his company) made a test CD. "Mono" means the same signal in both channels, so it should appear dead centre. "Band-limited" noise is a hiss containing only one range of frequencies, so you can check, for example, that just the bass sounds centred on the dash. A bass guitar and a piano are each placed at five positions from left to right. One track has a person talking and singing in two completely different rooms. EDM (electronic dance music) tracks check that the punch of the bass comes from the front. He says the tracks let installers without a deep musical reference confirm that left is left and the centre is the centre.
5.7 #9 · His reference tracks.
Van Morrison "Lonely Avenue" and "Ancient Highway", Herbie Hancock "Sly" and "Rockit", Marcus Miller "Blast" for midbass, Lyle Lovett "Flyin' Shoes" for lossy tests; judge with older music you know well. Without a centre image he can't even judge tone. Sources: SQOLOGY Pt 2 @46:07 · OFCAP 19 @3:43:08
In plain English: These are songs he uses to judge a system. He chose "Lonely Avenue" for its excellent recording, great imaging, very high crest factor (a big gap between the loudest peaks and the average level) and his emotional connection to the song. "Midbass" is the upper part of the bass range. "Lossy" formats, such as MP3, make files smaller by throwing away sound the format's designers judged hard to hear; he uses "Flyin' Shoes" for its high-frequency ambience when comparing them with the original. His advice is to judge with older music you know well. The last sentence matters most. He will forgive flaws in tone, such as a peak or dip in the frequency response, but without a centre image he can't even judge whether the tone is right.
5.7 #10 · Some listeners genuinely dislike a centre image.
Of two famous producers, one loved a centred demo car and the other heard it as "mono"; an earbud listener hated a pro SQ tune. Save the correct tune as a preset and, to blur the image, shrink delays rather than deleting them. Sources: B2 @41:19 · OFCAP 19 @1:14:04 · OFCAP 38 @1:02:06
In plain English: A centre image is not everyone's taste. He demoed a car with a clear centre image to two very famous record producers. One loved it. The other heard the centred sound as "mono", as if it came from one point, and hated it. Another listener, who did most of his listening on earbuds, hated a professional SQ (sound quality) tune. "Delay" is a processor setting that holds back the sound from the nearer speakers so that sound from every speaker reaches your seat together; it is what puts the singer in the centre for one seat. His advice: save the correct tune as a preset (a stored setting), because listeners often grow into it later. If the customer wants a less focused image, make the delays smaller rather than deleting them. He explains that delays also keep the bass coherent, and "nobody hates coherent bass".
5.7 #11 · Genre and mastering change what drivers receive.
EDM sends less power to mids and tweeters than pink noise, jazz more; compression belongs in the player, not the master, and the loudness war raises average power on speakers. Sources: Audiofrog blog Dec 2020 · OFCAP 19 @23:02
In plain English: Pink noise is a test hiss with equal energy in every octave (every doubling of frequency); it is commonly used to test speakers. His point is that real music doesn't spread its power the same way. EDM (electronic dance music) sends less power to the midrange speakers and tweeters (the small speakers for high notes) than pink noise does; jazz sends more. "Mastering" is the final step of making a record, where its overall sound and loudness are set. "Compression" squeezes the loud and quiet parts closer together, so the average level rises. The "loudness war" is the long trend of making records ever louder this way. He says it raises the average power the speakers receive. He says compression is useful, but argues it belongs in the playback device, not baked into the recording.
5.7 #12 · Distortion on only some tracks is usually in the source.
Many streaming mixes are clipped and phone "volume levelers" add more; if it persists with the phone turned well down, it's the track or the codec. Often the fix is simply turning the phone down. [RARE] Sources: DIYMA 2021-10-11 · DIYMA 2021-07-08
In plain English: Distortion is a harsh, gritty sound that wasn't in the original music. "Clipping" happens when a signal is pushed past the maximum level a device can handle, so the tops of the sound wave are chopped off, which sounds harsh. Many people hear distortion and assume a speaker or amplifier is at fault. He says that when it happens on some tracks and not others, the cause is usually the source. He suspects many mixes made for streaming are already clipped, and that phone features called "volume levelers" add more. His test: turn the phone's volume well down. If the distortion is still there, it is in the track itself or in the codec (the method used to compress music for streaming over mobile data or Bluetooth). Often, he says, the fix is simply turning the phone down.
5.7 #13 · Know when to stop: "imagine how much better…" is the biggest threat to satisfaction.
Keep a notepad, log tracks that annoy you, check that frequency with pink noise, and fix only real peaks; cutting everything that sometimes annoys you ends in a "smile" curve that sounds bad. [RARE] Sources: DIYMA 2022-03-03 · DIYMA 2021-08-30
In plain English: Tuning can go on forever, so this is about when to stop. He says the biggest threat to being satisfied is the thought "imagine how much better it would sound if…", along with forum claims that some new trick made all the difference. Recordings differ, and he advises against retuning the car for every one. His method: after tuning, keep a notepad in the car. When something annoys you, write down the track and the time. Later, play that passage while watching an RTA (real-time analyzer, a screen showing how loud each frequency is) to find the offending frequency. Then play pink noise (a test hiss) and check your system's curve there. If there is a real peak (a frequency that is too loud), fix it; if not, the sound is in the recording. A "smile" curve is an EQ shape with the middle turned down, so on a graph it looks like a smile. Turning down everything that sometimes annoys you ends there, and it sounds bad.
5.7 #14 · Hearing fades with age, so pair experience with a microphone.
Most men his age hear little above about 15 kHz (he hears to about 16 kHz). Sources: OFCAP 19 @1:35:05 · DIYMA 2016-02-01
In plain English: Hz (hertz) measures pitch: low numbers are deep bass, high numbers are treble. 15 kHz is 15,000 Hz, very high treble. The ability to hear the highest frequencies fades with age. He says most men his age don't hear much above about 15 kHz, and he himself hears to about 16 kHz. His point, made while agreeing with another forum member, is that even "golden ears" fade, so experience is best combined with a measurement microphone rather than relying on hearing alone.
5.7 #15 · How we localize, and why "height EQ" fails.
Arrival-time cues (about 80–800 Hz), a weak zone to about 1.6 kHz, then level cues; little localizes below 80 Hz. HRTF is about moving heads and moving sounds, so EQ peaks to "raise the stage" misunderstand it. [RARE] Sources: DIYMA 2016-04-27 · DIYMA 2020-10-14
In plain English: "Localizing" means working out where a sound comes from. He explains that our two ears use different clues in different frequency ranges. From about 80 to 800 Hz, the brain compares when the sound arrives at each ear. From about 800 Hz to 1.6 kHz (1,600 Hz) is a weak transition zone where localizing is poor. Above that, the brain mainly compares how loud the sound is at each ear. Below about 80 Hz, we can hardly tell direction at all. HRTF (head-related transfer function) describes how your head and ears change a sound depending on where it comes from. Some tuners add EQ peaks and dips that copy these height clues to "raise the stage". He says this misunderstands HRTF, which is about moving heads and moving sounds. A fixed EQ change works only while you are making it; afterwards your brain accepts it as normal tone, and the stage settles back down.
5.7 #16 · Your head never stops moving, which hides treble comb filters.
Above about 1 kHz narrow peaks and dips shift with an inch of movement; that's why sine tones mislead and band-limited pink noise or music doesn't. Car reflections arrive too early to be echoes; they become image spread and tone. Sources: Audiofrog blog Jan 2021 · DIYMA 2017-07-12 · DIYMA 2015-11-01
In plain English: When a sound reaches you both directly and as a reflection off a nearby surface, the two copies add up at some frequencies and cancel at others. On a graph this makes a row of narrow peaks and dips like the teeth of a comb, so it is called a comb filter. In the treble, above about 1 kHz (1,000 Hz), these peaks and dips shift when your head moves even an inch. Because your head is always moving slightly, you don't hear them with music. A sine tone is a single pure frequency, so it can sit right in one peak or dip and make it obvious. That is why he says sine tones mislead, while music, or pink noise limited to one band, spreads across many frequencies and doesn't. In a car, reflections arrive too soon after the direct sound to be heard as echoes. Instead, he says, they spread the image and change the tone.
5.7 #17 · Immersive multichannel wins ordinary listeners, and nobody is really a "purist".
Upmixing is for music too (use 5.1, not 3.1); real homes run multichannel and so does his JBL home system 95% of the time; an L-Acoustics multichannel concert was "a comforter of sound". Anyone who uses a bass control isn't a purist. [RARE] Sources: OFCAP 38 @41:02 · DIYMA 2021-09-09 · B2 @48:18
In plain English: "Immersive" sound surrounds you instead of coming only from the front. An upmixer is a processor that takes an ordinary two-channel stereo recording and spreads it across more speakers, such as a centre speaker and side or rear speakers. "5.1" means five main channels (front left, centre, front right and two surrounds) plus a subwoofer; "3.1" has only the three front channels plus a subwoofer. He says upmixing isn't just for movies; it works for music too, and he says to use 5.1, not 3.1. Non-audiophiles who heard his upmixed demo car said the sound was everywhere, yet the singer and instruments were still in front of them. He notes that real homes run multichannel, and his own JBL home system plays music in multichannel 95% of the time. A multichannel concert on an L-Acoustics system felt to him like "a comforter of sound". Many people believe a "purist" must play stereo only as stereo. His reply: anyone who uses a bass control isn't a purist either.
5.7 #18 · A binaural dummy head is a listening and teaching tool, not a tuning shortcut.
Its response changes with angle, it conveys imaging but not loudness or impact, and tuning with an "ears" mic would need a whole new target. Sources: CMA 2023 @55:01 · DIYMA 2021-11-23
In plain English: A binaural dummy head is a model of a human head with a microphone in each ear. Recordings made with it, played on headphones, sound much like being there. He sees it as a listening and teaching tool. For example, a shop can record a finished car with it so people can hear the result on headphones. Those recordings show imaging, but they can't convey how loud the system is or how hard the bass hits. It is not a shortcut for tuning. Its measured response changes with the angle the sound arrives from, so each speaker location would need its own correction. A "target" is the ideal frequency-response curve you tune toward. Tuning with an "ears" microphone would need a whole new target, and he says there is nothing to gain from it.
5.7 #19 · Don't measure the top octave through Bluetooth, MP3 or a laptop's own output.
Most "nothing above 10 kHz" complaints come from 128k rips or Bluetooth; laptops can filter test signals in the OS and phones can clip at full volume, so use an external sound card. Sources: testgear.audiofrog.com (COMPANY) · DIYMA 2021-12-05 · DIYMA 2021-12-22
In plain English: An octave is a doubling of frequency; the "top octave" is the highest treble, roughly 10 to 20 kHz. When people measure their car with test noise, a common complaint is that the microphone shows nothing above 10 kHz. He says most of these cases come from the test signal, not the speakers: the CD was ripped to a low-quality 128k MP3, or the signal was sent over Bluetooth. Both are "lossy" (they throw away some high-frequency sound to save data). Laptops can also filter test signals inside the operating system, as speaker protection that can't be switched off, and phones can clip (distort) at the top of their volume range. So in practice: play test signals through an external sound card.
5.7 #20 · The best "hi-fi" sound he ever heard came from a pro line array.
Ray LaMontagne on JBL VerTec beat anything at a hi-fi show; loud and clean aren't opposites. Source: OFCAP 19 @3:45:01
In plain English: A line array is a tall column of speakers hung at a concert venue to cover a large audience. JBL VerTec is a professional line-array system. He heard singer Ray LaMontagne at Town Hall in Manhattan through one and found it more "hi-fi" than anything at a hi-fi show, where expensive home systems are demonstrated. His point is that sound can be loud and clean at the same time; the two aren't opposites.
5.8 Who Andy is (profile)
What this part is about: A short profile of Andy Wehmeyer's career, so you can judge where his advice comes from.
Installer first. Built speakers as a teen, was a "terrible" installer at an El Paso shop, became its box builder (box software on a DOS PC around 1989–90) and spent about ten years at retail, ranking in Installation News's top 25–50. SQOLOGY Pt 1 @6:03 · B1 @1:57 · B2 @7:27
About 18 years at Harman from about 1995–96. Hired by Mike Giffin as Infinity class-D trainer on his former boss's recommendation; trained as far as the Audax factory in France; worked beside Richard Small, Floyd Toole and Sean Olive. SQOLOGY Pt 1 @11:00 · B1 @11:47
Product leader. Global Product Line Manager for JBL/Infinity/Harman Kardon car audio; drove MS-2 and MS-8 (the MS-8 auto-EQ was designed by Ulrich Horbach, he notes); designed the Infinity Perfect 10 VQ sub and an analog all-pass imaging switch in the Basslink. SEMA 2012 · DIYMA 2017-06-28 · DIYMA 2021-12-15
DSP user since 1992 and co-inventor. Co-holder of US patent 9,241,230 (extracting channels from factory systems) and an auto-EQ application; "not a coder or PhD acoustician" but qualified to teach tuning. DIYMA 2020-10-04
Left Harman in March 2013 as priorities moved to cheaper products for emerging markets. DIYMA 2013-03-02 · SQOLOGY Pt 2 @26:05
Co-founded Audiofrog with Gary Biggs ("GB") and Marcus Yeo; dealer-direct; calls himself its "customer service guy". [Conflict: founding year given as 2011, 2014 or 2012 in different sources; products shipped by mid-2015 and a 10th anniversary was marked in May 2023.] BusinessWorld · OFCAP 38 · DIYMA 2021-12-18
Origin of the "Harman" curve: his retail-installer curve became the MS-8 target and was later confirmed by Harman research. DIYMA 2020-10-14 · Audiofrog blog Mar 2021
A teacher by vocation: SEMA "Car Audio Mythbusters" (2012), KnowledgeFest tuning classes, Mobile Electronics columns, Audiofrog U, the Tech Blog and thousands of forum posts; in 2023 he shifted from teaching tuning to teaching system design (mapping a car with a mic and speaker before choosing locations). CE Outlook 2015 · B1 @1:00:14
Modest competition record by choice: tuned Team JBL cars with Gary Biggs; multichannel Mini and Volvo entries won shows. DIYMA 2011-04-16 · DIYMA 2021-09-09
Self-description: an "armchair acoustician" and "integrator, not a creator" who still finds phase plots confusing after 35 years. DIYMA 2011-06-09 · B1 @1:07:56
Caveat: he sells much of what he recommends (speakers, amps, test gear, an upmixer DSP); weigh product-specific claims accordingly, though he steers buyers elsewhere when Audiofrog doesn't fit. OFCAP 19 @2:51:01
In plain English: Andy Wehmeyer learned car audio hands-on. He built speakers as a teenager, then spent about ten years in car-audio retail, starting as an installer at an El Paso shop and becoming its box builder. He then spent about 18 years at Harman, the company behind JBL, Infinity and Harman Kardon car audio, where he managed those product lines, drove the MS-2 and MS-8 processors and worked beside researchers such as Floyd Toole and Sean Olive. He left Harman in March 2013. He co-founded Audiofrog (sources differ on the year). His background matters because his advice comes from both the installer's bench and the engineering lab, and he has taught it in classes, columns and thousands of forum posts. He calls himself an "armchair acoustician", not a PhD acoustician. He also sells much of what he recommends, so weigh product-specific claims accordingly, though he steers buyers elsewhere when Audiofrog doesn't fit.
5.9 Top rarely-discussed points in this section
Too little power can't blow a speaker; clipping roughly doubles average power and dumps it on the tweeters (5.1 #26).
With music a tweeter needs a watt or two; a big amp at full output can cook a passive tweeter without clipping (5.1 #28).
Amps with built-in DSP can leave a "1,000 W" amp making about 10 W after tuning; use separate DSP and amps for high-end work (5.2 #8).
About 70% of GB25 (2.5" midrange) warranty claims are DSP input clipping; set the DSP input so it can never clip (5.4 #12, 5.1 #61).
Move the image with level, never delay; 6 dB moves the centre halfway (5.1 #62).
"Bass up front" is crossover phase: lower the LR4 sub low-pass half an octave per 12 dB of sub boost (5.1 #65).
Only about 10–20% of a factory EQ corrects the speakers, so upgrade speakers on the factory EQ first; never sum a Logic 7-type system back to flat (5.3 #6, #7).
Factory systems are PhD-engineered; aftermarket people judge them on bass and miss their two-seat imaging (5.5 #16).
Buy from the best shop in town but ask it for a mid-level job (5.4 #1).
"Correct" is only the start of expertise; the disco customer shows when to back off it (5.4 #15).
Learn imaging with a $5 thrift-store pair before chasing concert references (5.7 #5).
Separate L/R amps and channel-separation specs are irrelevant next to in-car crosstalk (5.1 #24).
Break-in matters only for subs (5.1 #30).
"Individually matched" pairs signal a high-variance process (5.1 #35).
Premium buyers are 35–70 and decide with a partner, which shaped the Audiofrog name (5.5 #14).
Upmixers are missing from DSPs because of product managers, not licence cost (5.5 #20).
A correctly tuned car makes bad recordings sound better (5.7 #7); know when to stop tweaking (5.7 #13).
Distortion on only some tracks is usually clipped streaming masters or the phone (5.7 #12).
Changed views and conflicts in this section
Changed view, rear fill: 2017 forum recipes for differential (L−R) rear fill; by 2021 he advises plain stereo rears and says he may have helped make L−R fill semi-mythical (5.1 #75).
Shift of emphasis, efficiency vs power: "power is cheap" (2008–2013, arguing for active crossovers) vs efficiency first for very loud systems (2021); different contexts (5.2 #10).
Shift of emphasis, speakers' importance: 2008–2011 "speakers matter little if not badly designed"; 2016 onward, no DSP can remove a bad speaker's distortion (5.3 #3).
Shift of teaching focus: from tuning (about 20 years) to system design and measurement literacy in 2023 (5.8).
Conflict, gain-setting tracks: 2015 endorsement of −10 dB/multitone gain setting vs 2021 warning against using such tracks to max treble gains (5.1 #27).
Conflict, CES 1996 blind test numbers: three listeners after 700–800 demos (2022) vs four after about 1,500 (2023) (5.1 #21).
Conflict, LR4 vs 48 dB/oct protection: his claim that LR4 protects better is argued only from the "knee"; a note-taker could not reconcile it with attenuation one octave down (5.1 #57).
Conflict, Audiofrog founding year: 2011, 2012 or 2014 depending on source (5.8).
Conflict, tuning-guide structure: one description has the process in the first two pages followed by about 60 pages of explanation (2018 forum); another has about 40 pages of explanation followed by about 20 of process (Appendix A).
Consistent views (no change found): damping factor (2008–2021), break-in (refined, never reversed, 2015–2021; see 2.8 #6), tape-measure delays (2015–2021), cone-material scepticism (2013–2024).
The full series
Part 1: How Stereo Imaging Works in a Car, Reflections and Dispersion
Part 3: One Seat vs Two, Center Channels, Rear Fill and Upmixing
Part 4: Door and Midbass Installation, Sound Deadening and Speaker Locations
Part 6: Speaker Design, Driver Failures, Tweeter Protection and Wiring
Part 7: His Step-by-Step Tuning Process and Measurement Tools
Part 10: Time Alignment, Levels, Listening Tests, Processors and Common Tuning Mistakes
Part 11: Bass in a Car: Cabin Gain, Front Bass, Enclosures and Subwoofer Placement
Part 12: Power, Clipping, Gain Setting, Amplifier Specs and Noise
Part 17: Choosing a Shop, the Car Audio Business and SQ Competitions
Download the complete guide as one PDF (351 pages, every point with its explanation).
Comments