Good measurements equate to good sound? Strong bass with a small driver? A discussion with Harley.

#hifi #audiophile #measurements #stereo
Patreon: / thomasandstereo
Pearl Acoustics youtube channel / @pearlacoustics
My discussion with Harley regarding measurements in an audio context as well as how can his speakers get such powerful bass. I had to take out the section on how to choose a speaker blind without listening as the video was getting too long.
Gear used or mentioned in this video
Sibelius Loudspeakers

[@ThomasAndStereo]

Some of you have asked me for information about my new speaker. It will be a 2-way stand-mount speaker for around $2k. It is designed by someone who is used to making $10k+ speakers. For those who have not seen the Sibelius speakers video. kzbin.info/www/bejne/qH-1qKd_f7WnsLM Pearl Acoustics youtube channel kzbin.info/door/aDNKeOgZUaoEfj62C8jD7A

[@keianrobinson6305]

If you want, I’m willing to test your speakers Thomas 😁

[@nc3419]

Size, specs, material...let us know what to expect. I'm looking for a new speaker myself.

[@hansiangng2808]

would you send it to ASR? lol just kidding.

[@tthedon2471]

@@hansiangng2808 hahaha. what did harley say? he'll ignore them

[@carlitomelon4610]

I remember first hearing the Rega Ela transmission line speakers in the late 80s. I was amazed they could produce deep bass unlike my Proac Tablettes. Now I understand why. Thanks Harley! I later found some used Rega Naos TLs with 8in driver, a minimal xo design with 27hz bass. I'd love to hear the Sebelius....for now I'll be satisfied with symphony #7 on the LRS. Simon Rattle & Berlin Phil on Qobuz 🎶🤫🎶

[@jeffreypicciolo7706]

Among the most fascinating and educational interviews I ever heard. Harley is a master at explaining acoustics. His reed analogy was brilliant, and the explanation of using the cabinet as an extension of the driver was eye opening. Now I know why conventional speakers are bass limited by the enclosure/driver and his are much less so. Thomas - well done!

[@RGMDG]

Agreed. Really enjoyed the insight and experience that was shared here.

[@theoracleprodigy]

He really didn't explain that they are using a transmission line in the box. It's like a long port of sorts that's tuned to a frequency. He used that to tune his box probably for low frequency. Also I agree he was very interesting.

[@alistairwilson5344]

@@theoracleprodigy Yes, I really wanted to know more about his tuning of the cabinet-almost seems to be more of a magic bullet than crossover design (though not in this case).

[@theoracleprodigy]

@@alistairwilson5344 I don't know that you can get software to really show the length and pattern to use. Also you have to have a driver that can handle it. Along with that it sounds to me like they tried several boxes to get it right.

[@amsb4dafunk558]

The reed is more like the drivers voice coil And The Three, and a Half Foot tube of the Oboe Is The drivers cone, and the speaker cabinet.

[@dank.6942]

The bassoon reed and pipe metaphor is perfect. Laws of physics and acoustics, easily understood. Great video. Greater guest!

[@ThomasAndStereo]

Couldn't agree more!

[@audiorick841]

Thomas, you make great interviews without pretense and you let the interviewee speak. You’re one of the reviewers I respect the most and I could listen to Harley speak for hours on end. Thank you both.

[@user-od9iz9cv1w]

I really like Harley. What a generous, smart and cool dude. This video makes me even more a fan of his speakers.

[@estenray6685]

WowThomas!!! What a delightfully enlightening and entertaining interview! Harley is an amazingly eloquent person with such a warm, inviting and engaging personality! His joy and intellectual engagement with his chosen field of expertise is contagious! Absolutely delightful! Thank you Thomas for asking just the right questions! Your interviewing skills are quite impressive!

[@astertm99]

It’s always a pleasant experience to listen to Harley. He is a very knowledgeable and respectable gentleman. Thanks Thomas for inviting him for this discussion.

[@Benvos]

I love Harley, he’s so articulate and you can hear his passion so clearly. I can listen to him talk about hifi and music all day.

[@jaakanshorter]

I love technical interviews like this explaining things.

[@playbackvintagehifihunter9669]

His honesty is compelling. Watching this throughly engrossing video, I've come to a realisation that the real science is not the Speaker Response Frequency, or the soundwave between the speakers and our ears. The real science is between our ears and brain 👍

[@playbackamusicloversjourne8620]

I really like listening to Harley and his overall manner - serious real world experience, approachable and very quick.

[@ronaldweed6103]

Thank you ! Thus far this is the best interview I've ever seen or heard. The reason is because I understand mostly what is being stated.

[@giovannitirado6229]

Wow. Amazing interview. I learned a lot. Please post the second part.

[@christopherward5065]

Harley is such great value as a person. Always engaging and insightful.

[@m.9243]

Harley has an extraordinary ability of explaining concepts. This discussion made this absolutely obvious with the analogies he used. A great educational interview, thanks to both of You guys. And, if possible, please repeat the exercise soon by discussing relevant audio matters. A pleasure to hear you both! 🙂

[@redstarwraith]

Fascinating interview. Kudos to you both!

[@oldschoolaudioenthusiast]

This was a great / thoughtful / insightful discussion. Your subscribers and regular viewers really appreciate the approach you routinely take in all of your videos. Thank you!

[@hificave]

My favorite video so far. Thank you Thomas, and to Harley for taking the time to do this.

[@Nick-sk1qp]

Hi Thomas, thank-you for sharing your journey with respect to your speaker project. Harley has the ability to communicate his experience so precise and yet in a simplified way that I could almost visualize what he was saying. Fantastic interview, it kind of reminded me of the “master and the student” in a good way!

[@davidbailey6350]

I think that was an absolutely fantastic interview. A ton of information and a hell of a lot of stuff to think about

[@davidsagarra9841]

Fantastic interview!, really, extremely interesting!, worth to watch more than once to learn valuable concepts. Thanks!

[@JamesJohnson-oq6be]

Brilliant discussion. I thoroughly enjoyed it. Thank you

[@Mrhifitunes]

No one can explain complex things so easy like Harley can. He know his business and has a heart for music. Great guy.

[@techrider2088]

Harley-an artist and a genius. Thank you sir!

[@anthony5283]

This was great. Enjoyed every minute of it.

[@anthonyhopkin]

Fascinating, Thomas. Thanks for sharing this. Looking forward to part 2. Greetings to you and yours.

[@fonkenful]

The thumbnail photo and Harley’s name gave it all away to me. Mark Fenlon is a very accomplished and crafty speaker driver designer, whose products I enjoyed immensely in over 10 years of my DIY speaker building career; in fact my current small room home theatre Atmos system includes 9 channels of his “small” metal cone drivers. Thanks to the bass management baked into modern AVRs, it’s a piece of cake to protect such smaller drivers from the threat of over excursion in the bottom 2 or so octaves and feed that to multiple dedicated sub woofers. Within carefully considered use cases, a pair of nominally 6” full range drivers can deliver very satisfying musical or movie soundtrack experiences. Thanks to modern modelling software readily available to enthusiastic amateurs and professional designers alike, enclosures can be optimized to the T/S parameters of individual drivers, resulting in performance that punches way above their weight class. Mark Audio has also made several models of paper cone drivers - which I’ve also enjoyed - but as of this writing (April ‘24), I think those models have been streamlined.

[@stevenbeau6268]

50 some years ago, I worked with Amar Bose. This is very much dejavu. Great video…s

[@jaybowen2235]

Great discussion, information, and explanations of speakers, acoustics, etc.

[@clarencehoover6748]

Fascinating, lovely conversation with Harley. Definitely a worthwhile experience.

[@kuisin88]

This is a very educating video. Awesome job Thomas.

[@2010aloy]

Love your videos Mr Thomas. Super interesting discussion. Take care & keep them coming.

[@jblesser]

What an extraordinary video. Thank you very much.

[@edelweisskoenig]

What a fascinating and enlightening video. Harley is also spreading such an all-round positive vibe, wonderful.

[@Ronildoquek]

Fantastic video! Enjoyed it !

[@kennith.]

Thomas that was very informative. Thank you Please give Harley our thanks.

[@jeremyaguilar3805]

Fascinating! I never had confidence in single driver speakers. Now I do.

[@sama7545]

This was a great interview!

[@petervansa2477]

this is GREAT interview. So, full if information - actually, not on the topic how to build - but what and how we listen, and what we should listen to. Thank you!

[@ThomasAndStereo]

Glad you enjoyed it!

[@njalbrekke4861]

Very interesting! Want to see it again👍

[@humanitech]

Great discussion covering the wonders, realities , complexities and refinement of music, sound, instruments, technology and reproduction ....spot on!

[@carlitomelon4610]

Exactly my first impression (#1) 🎶☺️🎶

[@daniellustgarten5857]

THANK YOU FOR THIS BEAUTIFUL ,FORMATIVE AND EDUCATIONAL VIDEO

[@jfbaquero]

Great interview. Harley's channel is amazing, but hearing the man talk about instruments and it's correlation with speakers is amazing!

[@billbones1000]

Captain Kirk shirt and chair, Picard head. Fascinating. Joking aside, this gentleman has talked more sense in this interview than I've ever heard in the audiophile universe. Imagine, a designer who thinks about instruments......so refreshing!!

[@saltflyer]

Brilliant! Good to confirm we should keep on using our ears to listen to music and not our eyes..

[@stephencharlton2024]

Just excellent. Thank you.

[@dajikbatarang1]

This was a great interview, excellent video Thomas.

[@TorToroPorco]

Fabulous interview and a valuable lesson on wave propagation and amplification. Wave propagation mitigation is also an important component in the design of stealth aircraft.

[@ivandyap]

Thanks for the erudite discussion! Very informative.

[@edwardwood969]

Harley is fascinating to listen to. Thanks Thomas for sharing the interview.

[@lexx6450]

Fantastic. I learned so much!

[@ThomasAndStereo]

Glad it was helpful!

[@snobi76]

Very interesting video, learning alot, thumbs up :)

[@leonardobrito6567]

Harley’s a real guru of sound and a real gentleman.

[@richardherbert3519]

Brilliant video

[@adamcfada5071]

Very informative and interesting. Looking forward to the second part. 👍👍

[@ThomasAndStereo]

Glad you enjoyed it

[@albertorobinson7611]

Highly appreciate, thanks for everything and cheers

[@MrGorpm]

What a great video. I have learned more about loudspeaker design from this interview than I have gleaned from over 50 years of hi-fi system ownership, I am very glad I caught this, and I'll be watching the second half as soon as it is uploaded. I have been aware of the Sibelius speakers for a few years, but I'm not totally convinced that they suit my musical tastes well enough to warrant a purchase.

[@labernese]

I quite enjoyed this interview Thomas, thanks for bringing this kind of content to your audience. These longer interviews may not get as many views but I think they really add to your channel 🍜

[@net_news]

great interview Thom! Congrats!

[@Jos3Miguel]

What a good conversation! Who knows what's talking about makes it simple for others to understand, this is the case. I like single driver speakers, at the moment we have two-way speakers with closed box (24" high / 9" wide / 14" wide), however there is still so much to try. Best wishes for personal projects! Kind regards form Portugal.

[@freelancer1499]

Woah the man is sharing his life experiences and knowledge on audio, and just for free haha. Imagine the cost engaging consultants @ this level. Great content Thomas. I enjoyed this!

[@erikhoogantink8529]

That was a great explanation of a transmission line speaker.

[@joeycastillo1496]

This is a good educational learning about single driver enclosure’s

[@eddietours3728]

awesome video

[@housemadeoftruth]

More please… definitely make a second video of the rest of your interview with Harley! 👍

[@PanAmStyle]

I have a few favourites on KZbin, Thomas & Harley are at the top of the heap. And this discussion is one of the best ever. The “frustrating” thing is that even though I’m “set” for my speakers, I am really wanting to hear the Sibelius! Cheers to both of you and *thank you* for generously sharing with us.

[@ThomasAndStereo]

Wow, thank you!

[@Projacked1]

Beautifully explained, now I truly get it....

[@Projacked1]

Understanding audio is like a repeating cycle of going back to basics and realizing what you could have done in the first place...right? It's same in the studio-world, with trying to figure out (the final) recording related to the compostion of a song/ piece. Even the best ideas can fail in a second (because of reality catching up vs your imagination ). Mix that with audio purity and your asking for rabbitholes. Moral of the story there ; trust your ears vs measurement. If it sounds great-> next step I love it! haha....keeps the mind focused ;)

[@Projacked1]

One of the best questions ever Thomas, kudos from the Netherlands!

[@MisterJDee]

Wow! Fantastic interview! I am so desperate to hear one of Harleys speakers now!

[@ThomasAndStereo]

Glad you enjoyed it!

[@waynetoneseekerandersen2213]

This guy is wonderful, thanks Thomas for bringing us Harley

[@ThomasAndStereo]

You bet!

[@toddhupp]

fun interview. looking forward to the Thomas creations.

[@CP-oe3kt]

Most amazing video/interview I've ever watched. Thomas, you continue to hit it out of the park with your channel. By far and away, the best Audiophile Channel anywhere!

[@WDMM75]

Excelentes preguntas amigo. Saludos.

[@markscott7583]

Love this video - more like this please :)

[@nmahamad]

Advice you won’t find in a textbook or went to a class for hours. Good video Thomas

[@Bd-ox4mi]

This guy has saved me 💰💰💰great job Thomas ✌️

[@iliascharis5668]

Very nice chat 👌

[@knobbshots]

That was fascinating for sure, wish i could like it twice

[@Linnjazzy-93]

I learn a lot , thanks you

[@ThomasAndStereo]

Glad to hear that

[@Linnjazzy-93]

@@ThomasAndStereo after watching your video I decided to contact a speakers designer to build my own speakers, let see

[@mayssebmasenya9132]

Brilliant 🤩. I was dreaming about the Sibelius speakers after your review. After this, I have to find a distribution line to South Africa 🇿🇦. Fantastic talk.

[@NosTubes58]

Beautiful educational video……., thank you both for explaining speaker design in detail. Thomas I’ll be keeping my eyes ( ears ) open for your monitor reaching the market, as someone whom has to date owned over 25 pairs of Mini-Monitors starting with a pair of Rogers LS 3/5As in 1979, which stationed in Japan, it goes without saying, I’m a small speaker lover by choice.

[@labalo5]

This is what drives me to inquire about new speakers. I hope these Sibelius will be at my next local show

[@scottbaylor6215]

Not knowing much about acoustic science, I really enjoyed listening to this. He is very knowledgeable and loves his passion. Keep rocking. 🤘🏼🎸🤘🏼

[@ThomasAndStereo]

Glad you enjoyed it!

[@raphaelmeillat8527]

Fascinating interview! Hartley's got to be one of the most interesting people in the music industry! His passion for both musicians and acoustics comes loud and clear! (pun intended!)

[@Novilicious]

That point about bass blew my mind! Such a great podcast. Also, add a rel sub if more bass is needed

[@matthewtolson7465]

Class video Thomas. I paused half way through to have dinner! Not a criticism in any way, completely riveting stuff which deserved my full and undivided attention.

[@thirdkey9]

Space station broadcast is still quality over polish and such an excellent interview. Like many have stated, a fascinating interview with a passionate pro and with a few aha moments. Hope you elect to do more if time allows. Best on your mission in bringing your stuff to the marketplace.

[@denniswade4998]

Thomas, this interview and the knowledge that is shared is exactly the reason why I watch your channel over so many others. No one else is really doing what you are doing. With so many reviewers, all that i get is their personal view of whether a piece of gear sounded good to them. You, on the other hand, have taught me so much about how different pieces of gear work, why they work that way, and what kind of sound I can expect to get from them. I know that you often worry about why your viewing numbers are lower than some others , but you need to remember that gauging your KZbin success by subscription numbers only is kind of like judging a piece of stereo gear by its measurements only. The numbers may look great, but if you look deeper, a lot of their popularity is due to oversimplifying the whole process of piecing together a system that has good synergy and will work well in your room and with your particular music tastes. People like to hear that you can just pick gear that a reviewer says is good and throw it all together and expect to have great sound. And there are a lot of reviewers who feed into that idea. You just look over the list of components that they say sound good , pick out your choices, and expect it all to work well together. Your success lies in going deeper and helping us to understand why some gear works well together and how to make better choices. It's more work as a consumer and there is more effort involved in making good choices, but I would be willing to bet that the people who watch your channel have learned more about building a system and as a result, have more enjoyable systems as a result. And THAT is what makes you a success !

[@ThomasAndStereo]

Dennis, thank you thank you for the kind words. I keep making these videos thanks to encouraging comments like these. I know if I made a video on a budget speaker, it would get a lot more views but these kind of videos are more meaningful for audiophiles.

[@doctormidnight]

This is a really good one, lots of info to process but you seemed really encouraged by what he had to say. Now I want to see the rest of the conversation. The comments regarding GR seem spot on. I can't remember the last time Danny said anything about how a speaker sounds, what it feels like listening to it, what "holy crap" moments he had when a certain piece is playing. It's really odd. Maybe he's just not good at coming up with a way to convey that sort of thing, but it's hard to be generous to a guy that put out a video with a ton of exaggerated accusations and a huge dose of what sounded like financial gatekeeping. Oh, about SMSL: some sly person sent me an early birthday present and I now have the SA300 running the 706s. This thing is crazy good! I love being able to run them full range with the little sub, which I couldn't do with the Denon that cost 4x as much.

[@birgerolovsson5203]

Very interesting and nice "interview".

[@ThomasAndStereo]

Thanks for watching.

[@allanellis5827]

Great video. Very interesting and educational. It appears to me that people should be very careful in modifying their speakers in an attempt to get a flatter response. I assume most speaker manufacturers are voicing their speakers to achieve a specific sound. Above all I think people should purchase a speaker that sounds good to them and leave it at that. Modifying a speaker's sound can potentially backfire and create a speaker that sounds bad if not terrible. Can't wait to see the continuation of this video. Thank you so much!

[@frostycanada6404]

Hello Allan, that’s exactly right. I’m not aware or I have never seen someone do an A/B check post modification to see if the changes implemented were actually beneficial. Brian

[@AmazonasBiotop]

@@frostycanada6404 Oh, then you missed the part where Thomas said that he got mail from people that thought that after modification it were super and others that it were bad (modification of the RP-600M). That is individuals that experienced A/B (before and after) on a speaker they own and living with. (Remember that there is a risk that someone has wired them wrong in the process and is a factor why they think they sounds not that good.) The good thing is that the ALL ACTIVELY were willing to learne something and in the end grow by knowing more than they did before. 🥰

[@frostycanada6404]

@@AmazonasBiotop Hello Optimized, I heard what Thomas said about people upgrading their speakers and the before/ after experience of the mods but I was more thinking of GR Research. He always talks about selling his upgrades but never shows a blind A/B to see if the changes are actually beneficial to the buyer. I remember Axiom audio doing blind testing with crossovers. One set of speakers had two built in crossovers that were switchable on the fly … one crossovers with cheap regular parts the other top quality. Results = no discernible difference. Take care, Brian

[@samidanger3666]

Cheers Thomas, it just suddenly clicked in me that you're a really good dude..! 😋👍

[@ThomasAndStereo]

I appreciate that!

[@DeAudiofilosyLocos]

I thought I saw an English horn Reed! I did a feature on my channel where I compare having many reeds as a justification for collecting phono cartridges 😂 great to see Harley support double Reed players!

[@mikehuntington4440]

That was really good. I never really thought about it the way this guy described bass of an instrument with a reed. I actually have an 8-in single driver floor standing speaker.. it measures like crap, but really sounds great. The only problem larger wideband drivers is they can become very beamy and directional. I've had a 4-in wideband driver speaker as well and it had better off axis response.

[@ThomasAndStereo]

Glad you liked it!

[@RJ_Chicago]

Thomas, Great interview! I like Amir too. But the entire measurement vs perception/listening is a conundrum. While measurements have value. No one is going to want a good measuring piece of gear that sounds terrible. But also consider this and let us or me, know what you think: Amir measures gear with sophisticated and calibrated electronic measuring devices that do not take into account the acoustic properties of the room and of your/our hearing. If our hearing and brain were of similar sensitivity and calibration as Amir’s gear than perhaps all his good measure gear would sound good and all the gear that measures poorly will sound bad. But the thing is, our ears are far from uniform across people, our hearing is imperfect. Age, environment, medical conditions, etc can effect our hearing and so can the room or placement of the gear. So we are trying to perceive good measuring gear with very flawed organic microphones, our hearing and brains inside different and acoustically flawed rooms. It’s just not going to match up properly. I think this is why often good measuring gear may sound lousy and bad measuring gear sounds great. But since we listen with our flawed hearing, brains and rooms, that trumps the measurements. That’s the bottom line.

[@DougMen1]

You also have to take into account people's tastes. One person's crisp and clear may be harsh, thin, and shrill to someone else. Conversely, one person's warm and sweet may be dull, bloated, and muddy to someone else. The problem I have with Amir is that often the measurements that he trashes are inaudible, even if they aren't as good as he's seen from other gear. If one amp/DAC or whatever measures .03% distortion, and a SINAD of 70db, while another cheaper one measures better, so what? Who cares? No one can hear .03% distortion or noise that is 70db below the music signal, so it doesn't make any difference!

[@commane21]

Amir would agree with you. At risk of misinterpreting him, I conjecture that devices that measure poorly in exactly the same way would sound similar to each other. Distortion is often thought to take away from sound quality, but the sort of distortion produced by many tube amps and preamps sound terrific to some listeners. If you told Amir you preferred the second order stuff of a MacIntosh, he’d likely be able to tell you what other amps measure “poorly” in that same way and you’d be off to the races.

[@scottypalmer2158]

I don't know. I have taken three different 5 1/4 woofers that sound very well by themselves. But once I pair each woofer with the same tweeter at the same crossover things begin to change. In this example the least accurate woofer actually sounded better with said tweeter. It seems to be a frequency relationship between drivers that creates the final sound. A certain tweeter may enhance or hinder a certain driver's characteristics. I could not foresee this outcome but in this case the best measuring driver was not the winner.

[@DougMen1]

A dip in a speaker's response with be much more audible at some frequencies than at others, and, of course, how steep the dip is, and how broad it is, will definitely affect how audible it is too. If I were in your position, I might build a different crossover that corrects the dip and compare the two to see which one I prefer.

[@impuls60]

As a designer you need to understand the consept directivity index. Eric's audio corner is a great source to understand how importance this is. The analogy used here is to simplyfied to learn enough to make a speaker that sounds excellent. Radiation patterns and lobes are much more useful to understand how a speaker is going to sound.

[@saverioricchiuto5386]

This conversation is no nice: everything is put so clearly, nicely, unbiased, factive…I wish all divisive topics could be discussed like that: I’m positive everyone would eventually stick to his beliefs, but no one could avoid admitting their counterpart has really good points. Can’t wait for “Part 2”

[@psyphonyxaudio]

FINALLY !! ..🙏🙏❤️❤️

[@analogkid4557]

TL speakers are tough to design but when you get it right, they are amazing.

[@mpp9964]

I like to see I’m not the only one who doesn’t feel comfortable putting the subwoofer anywhere other than right between the main speakers

[@jusjash]

After 15.51 in this video I became enlightened , so I paused to make this statement : ""🥇🏆🏅"" Yeah , Thomas n Harley knocked this one out the park.