Lunch with Paul: Passive Radiators

PS Audio senior design engineer, Chris Brunhaver tells us what a passive radiator is, how it differs from a port, and why it's being included in the new FR Series of loudspeakers.

[@xanderguldie]

Love these conversations, I only wish it didn't look like a Project Veritas undercover spycam

[@FeeLtheHertZ]

lmfao

[@preddy09]

LOL, they did say ABR sounds like industry horseshit.

[@PebblesChan]

PR with a PR about PR with PR at a PR. (Public Relations, Precision Report, Passive Radiators, Paul’s Representative, Public Restaurant)

[@deathunitesus2135]

Puerto 🇵🇷

[@ericnortan9012]

pre-rolled

[@SuperMcgenius]

As a speaker builder for many years , wow I learned something. Can you do a talk on transmission lines? Also open baffles speakers. I have owned IMF , MAGNEPAN and Vandersteen 5s, plus many of my home builds that had Asymmetrical cabinet designs designs with crazy bracing and a tar sandwich with a quarter inch of softwood inside. Very f’ing dead. One inch HDF wood. . Thank you for sharing you deep Knowledge with us.👍😷🇨🇦

[@adrianbennett9322]

This was a really interesting and clearly explained topic! Chris seems more relaxed and animated here vs the solo videos, I would love to know half of the things he's forgotten about speakers 🔊 Great video thank you!

[@twraven1]

I don’t know how much I learned from this video but my loudspeakers, Piega C711s, use two woofers and two passive radiators, both front firing in a non-ported aluminum box and produce impressive bottom end.

[@poserwanabe]

Heard this on net, it's not mine but I loved it.... Sealed box is like listening to someone talk... Ported box is like listening to someone talk with a drunk guy next to him repeating everything he's saying..

[@Its_Montei]

Makes perfect sense

[@ericnortan9012]

I have always used ported subs. I decided to build one and went with a sealed box. I got the woofer and built the box to the recommended area for my 12" driver. I was impressed, it really was much tighter and cleaner than my ported subs. Next time I upgrade my subs I'm gonna go with a good sealed set, see how it goes.

[@PooNinja]

MDF passive radiator oooh wee that’s something I gotta see 🤘🏽

[@hom2fu]

with all those vibration, it won't last. why not try bamboo mdf

[@letsflywiththemusic]

Built a passive radiator sub several years ago when I was a young engineer. 2x jbl 8" drivers and a plate amp. Did no simulation or measurement tuning like I do now. Ended up with awesome low end extension for it's enclosure size. Measured recently and the response and phase is spot on, so lucky!

[@Chris_Wolfgram]

LOVE my two 15" PR's with one 18" sub in my truck :) Nicest sounding enclosure I've ever built, out of about 30 of them :)

[@Golddragon214]

I loved this conversation. Chris makes so much clearer in design of PRs and why some speakers just don't make sense with the design chosen by the manufactures. I can't wait to see your speakers and hear them for myself.

[@jeremyr722]

I like this lunch with Paul format. Keep em comin

[@FeeLtheHertZ]

Final comment but, Chris is one hell of a cool dude. Keep him on man, very interesting info, 100%.

[@user-od9iz9cv1w]

Fascinating. Learned a ton on this one, thanks. The interview format really brings out the best of both of you.

[@jonathannocon]

I can listen to these two talk shop all day is... 👌🏼

[@ToadStool942]

nice and very informative interview. Thanks, Paul

[@bigshot4kids]

Thank you for this Paul. Very informative, and I even understood it!

[@stimpy1226]

Great explanation Chris. I just learned quite a bit from this video.

[@trevorvantiel453]

I'm not sure who's picking the tab up on these lunch and learns but please keep them coming. What a great format. Chris's knowledge about speakers is impressive 👏 👌 I can not wait to see your new speaker line. Thanks guys! Thanks PS Audio!

[@charlesferguson6678]

damn... I'm looking forward to hearing this guys work!

[@uscaremealotyt]

Your engineering team is a godsend, i just wish i could afford PS Audio gear, i really do...Cant wait for the final piece in the chain.

[@user-xb4nn6ql5l]

OK best Chris B video so far. I've never been in any doubt that he's special in terms of knowledge and insight, but this interview format really suits him -- the passion, the enthusiasm... Also, very interesting topic! I learned a lot. A whole lot.

[@ssks1979]

Well, this was the most detail I've heard or read about PRs in speakers. My vintage Celestion Ditton 25 speakers use a 12 inch PR and my old ears have been happy since 1983. But I hope to listen to your new speakers when they are in showrooms to know what a quality modern design sounds like. Thanks.

[@steverogers7611]

Keep putting this guy on Paul

[@jimshaw899]

What I like best of Chris, and I like it all, is that he approaches reproducer design from a mathematical and scientific direction and background. That, as opposed to the myriad of prejudices and old wives' tales the 'speaker designers' have put forth over the years. It seems like Chris raises the bar in speaker engineering -- way, way above the old 'art form' design folk wisdom of yesteryear. I am looking forward to seeing and hearing his products. Of course, because they're from PSA, I'll ever be able to afford a set, likely at the price of a midsize car. But, from a distance, I can admire what science, as differentiated from art and cut-and-try, gives us. Great expectations, here. Now, to make them play in a room. Ah, there's a rub....

[@johnsweda2999]

Maybe they would do it as a kit forum! you buy the driver's crossover blueprint self adhesive veneer dampening material and get the cabinets made at a shop or yourself. shipping some drivers and across over and extras be very cheap considering a whole speaker in weight and size normally that's probably at least $300 saving just there let alone the savings in manufacturing in time and money, should be able to sell them for least then half the price and probably make more profit on it They go Paul what about it good option.

[@mattuw82]

Yeah that's a good point. You never will hear Chris talk about audio with the same vague, subjective biases that everyone else seems to. It's really refreshing.

[@skanf]

Thank you! This is the lesson I need :-)

[@Real.Estate.Motivate]

Very informative video thank you. I just picked up a mint Definitive Technolgy 14" 1800W Supercube Reference subwoofer that also has two 14" passive radiators on each side. I gotta tell you, this 100lb 16.5" square heavy but small enclosure is simply incredible. I had a Martin Logan Dynamo 1600x and to compare that sub to this isn't fair...it's not even close. It's fast, precise with both movies and music and delivers completely earth-shaking bass when needed and it's 11 years old! I have never watched movies before when a deep thud, a gunshot, door slamming, or when cars are crushing that literally scares the heck out of me. If you find one, just buy it...if you don't call me and I will. Absolutely sold on the small box, tubeless passive radiator technology. Amazing!

[@JonathanDFielding]

I want more! Explanation of the benefits and science of Passover radiators and how to design with them

[@rockindel1]

Thank You I have been using my PR speakers since the 1980s and love the clean broad frequency response my friends are often blown away by how clean they sound with a ton of low end. its nice to hear some of the science behind it

[@porkchopspapi5757]

What speakers are these?

[@rockindel1]

@@porkchopspapi5757 they are db plus 990 from the 1980s ,102db/w/m and are amazing for rock

[@porkchopspapi5757]

@@rockindel1 And yet another loudspeaker maker I've not heard of. Gona check it out now.

[@davidfreeman4625]

Very interesting, the knowledge shown here is amazing. Would also be nice to hear his views on Acoustic Suspension vs Infinite Baffle in the closed box space. Infinite baffle seem to have gone out of favour and seem to be ignored now.

[@kaedeschulz5422]

I love Passive radiators! Some designs wouldn't be possible without them because of a standard port not being able to fit inside the enclosure and as well as port resonances being a problem like mentioned. As someone who has used a Port and then switched to a PR of the same design because the port was too small and a bigger one didn't fit. The transient response is NOT worse! Like he mentioned it's a design problem :) The SB acoustics PR's i used have extremely soft suspension!

[@FeeLtheHertZ]

Def Tech is kicking back somewhere and just smirking with pride.

[@poserwanabe]

Exactly

[@Real.Estate.Motivate]

Totally agree...I just picked up a DefTech Reference and whoa! I've never experienced anything like this subwoofer...it's beyond excellent!

[@mattlong4102]

I like Paul, he'd be a fun guy to get a beer with.

[@thomasandersen1784]

Hey there....more speaker talk & that's just great...but....when are we to see/hear PS Audio's new line of speakers? We wait in patience, but..i'm so exited..!! Cheers from Denmark & stay safe!

[@ApEsXiT]

Paul youre genius for posting these videos in this format, bravo. Chris is the man. So happy he is designing this speaker for ps audio. Hey Chris what speakers did you help make at Adire Audio?

[@hugobloemers4425]

I like passive radiators more than ports. Also because you can easily tune them (or tinker with them) by changing weights.

[@Joshualbm]

It's incredible what the car audio guys are getting out of their small and large boxes with active woofers. They tend to use 2 woofers and a giant amp, maybe a port and often sealed. But it seems to me that if anyone ever tried to integrate one of Bob Carver's subs into a car, using a power inverter for 120v AC, of course, that you could pressurize a car so much that the windows would pop out. And that little box uses a passive radiator.

[@paulm944]

These "lunches with Chris" are awesome. I have been looking at the REL T/7i subwoofer and was wondering what the passive radiator was for. Keep going with these! Will PS Audio be making a subwoofer at some point? Thanks Chris and Paul.

[@erikkroll2154]

I used passive radiators in my studio monitors. Have them tuned to 28 hz.

[@loganemonds314]

Thank you for that explanation! I have been interested in passive radiators for a while but was not sure how to tune them. Just to make sure I am understanding correctly; given a port tuned to the desired frequency, a passive radiator with an equivalent area is tuned to by matching the mass of the radiator to the mass of the air in the port? No changes to the volume inside the enclosed minus port volume? How do you deal with multiple passive radiators, divide the surface area and mass equally between them?

[@johndoh2121]

Some interesting looking transducers in the restaurant behind them :)

[@Daniel-hk3ru]

Great!

[@MrRad21]

Great discussion, how about discussing transmission lines next?

[@hugobloemers4425]

I have a feeling PS audio does not like them.

[@woopygoman]

The Helmholtz resonator is a fascinating device.

[@timothyhenwood1576]

I have a pair of Klipsch Forte 2 speakers with a 12" passive radiator in the back. They sound great to me- although Paul probably wouldn't like the tweeter and mid-range horn design.

[@FeeLtheHertZ]

Doesn't matter what he likes, DO YOU like them?

[@TNPFan]

When I hear passive radiator, I can’t help but think of Sandy Gross.

[@andrejoao]

Is that bookshelf with the oval passive radiator the Buchardt S400? Are we going to see a PR in the PS Audio bookshelf yet to be launched?

[@longylongtime7823]

Plus one to this question.. it's an impressive speaker!

[@BastianUllr]

@@longylongtime7823 It's the Buchardt S400 - It's at their lobby. Check Chris speaking on this video with the S400 behind him. /watch?v=HeaoU-ccS7Q

[@cbrunhaver]

@@BastianUllr No, this was a prototype bookshelf that I was working on. There are a number of other bookshelves with PRs and yes, buchardt is one of them. We do have a set around the office, but this story was in reference to something else.

[@BastianUllr]

@@cbrunhaver thanks for the insight

[@thunderpooch]

@@cbrunhaver could you share some of the math behind how you like to use passive radiators in a design? And does it differ at all from conventional thought? Many designs today don't use MDF or heavier materials like you suggest. Would transient response ever be a concern?

[@vandecoteau9899]

What it you made a passive radiator enclosure that was airtight, removed the air, and replaced it with a gas that's lighter than air, would that make for even smaller boxes with higher SPL?

[@thunderpooch]

I was first going to laugh at you about air tight boxes and then experimentng with different gases. But honestly, it sounds like a brilliant idea since some speakers are already so expensive anyways. A pressure meter could be hooked up to an air supply so the pressure could be maintained and/or monitored even if there was minimal leaking. But I still think it would be pretty hard to make a driver an air tight barrier. That would be the challenge area.

[@ThinkingBetter]

For the deepest bass I prefer a closed box design with servo feedback for minimized decay and DSP compensation for equalizing against linearity issues. Ports and passive radiators can’t compete against a well designed active servo solution.

[@orangejjay]

Facts

[@markbushinski1198]

How does the decay time of a port and pr compare? A 1kg passive seems like it will take a while to stop.

[@audiomez]

If one needs convincing about the unmanageability of the universally present “natural resonant frequency” that resides in all solid masses go look up the news footage of the ribbon cutting ceremony of the worlds 3rd largest suspension bridge (the Tacoma Bridge).

[@HillsWorkbench]

More! This guy knows his $hit!

[@thomasjohnson6808]

I wish there was more background noise as I can almost hear the conversation.

[@stevekarr4613]

Chris is awesome. Is the bookshelf on it's way to market? Pkg deal with the Sprout II...

[@Paulmcgowanpsaudio]

I wish it was! No, we're likely a year away from the bookshelf. The first you'll see from us is the FR30, a bigger floorstanding speaker.

[@kcjones7634]

Port farting is the result of air struggling to escape, The reason for this is ports aren't designed for perfect air flow, it's just A tube, usually misaligned with the building of pressure in the speaker chamber.A short tube placed directly behind the woofer in a symmetrically aligned chamber would creat less port noise but the effect of low sounding bass would be lossed. The greatest solution would be to create A port That channels the AIR PRESSURE. WIND TURBINES channel air perfectly A port that has spiraled (air channels) With large flares would be best. A flared port that widens 4-6inches before reaching the rear of the speakers Yes BIG PORT FLARE . SUCH A GREAT DESIGN.

[@bruss529]

Spend lunch with the Boss, He grills you on highly technical material - oh and we're recording. No pressure there amirite?

[@jamesbaranowski8755]

What bookshelf were you talking about at the end? One of yours that is in the works or another company? Great video thanks

[@markflower8885]

A bookshelf/standmount speaker with an oval shaped passive radiator? Sounds like a Buchardt S400 to me. 🤔

[@sean_heisler]

Mark Flower that’s exactly what they’re talking about. They have pair in the PS Audio lobby.

[@nodata5539]

Pretty sure they refer to the S400’s. These bookshelf speakers are monsters. You would not believe until you hear them.

[@mattuw82]

PS Audio builds a ton of prototypes that they don't end up releasing.

[@genez429]

Smaller diameter ports are reported to give tighter bass... But, if the port is too small in diameter? It will tend to produce whining noise with dynamic passages. So, designers must make larger ports because they do not want port whining. Just the same.. some listeners find they like the music better with a little port wine.

[@gabrielr6679]

I'm just wondering for ported you must be a certain length to a wall, so what about a radiator do you still need to have a certain distance from a loading wall? Can passive radiators be very windy? Hair tricks... Not too much people doing passive radiator setups in car audio.

[@thunderpooch]

Does anyone have the math behind what Chris is suggesting? I'd love to attempt a passive radiator design using a lot of passive radiators or even mdf like he suggested.

[@finscreenname]

What speakers does Chris have at home?

[@finscreenname]

@Fat Rat NO WAY!!!???

[@curtchase3730]

I used to question the functionality of a PR myself. Were they a fad of the 80's? Did they actually help the bass? Hmm. Well, it seems Chris has shed a little light that they CAN work! I see PR's used in some portable BT speakers, but do they help in that environment? I learned PR's require careful tuning like ports. Determining size and mass are crucial I guess. I like the "nuts and bolts" approach Chris uses to explain a complicated subject. Since he has a thorough knowledge along with hands-on experience, he can down mix info in a way someone can understand it. Like a home builder with 30 years experience teaching a newbie how to build a house, VS someone who just read a book on how to build a house and then trying to teach someone else! 😉

[@FSXgta]

in BT speakers you can get splash/water resistan speakers much easier, and they don't have to be larger to fit regular ports and get the same effect

[@FeeLtheHertZ]

Of course they work, they work all the time. There's no "ONE ONLY GUIDE!" to speaker design.

[@trei2unu]

Have a listen to the Harman Kardon Onyx Studio 5 if you get the chance. A serious bluetooth speaker that's not that expensive and has two PRs (one in the front and one at the back to cancel the vibration probably). The PRs on thtat thing Really work, they produce very clean, tight low bass.

[@AmazonasBiotop]

I wonder if it was the Buchardt S400 they were impressed with at the end of the conversation?

[@AmazonasBiotop]

@Fat Rat What? Have I missed that ps Audio have officially launched a speaker? Looking on their site (from EU) there I see only images of sprout and ELAC speakers. And the text underneath also talking about ELAC. (That is not expected if PS Audio had their own speaker to push for someone else's speakers). Maybe in US they have launched speakers?

[@AmazonasBiotop]

@Fat Rat Oh nothing yet.. I definitely understand that when and if there will be any speaker coming out from PS Audio then they will be probably pricy. 🤔 When ps Audio have worked and developed them way before Arnie Nudell passed away 2017. Now a time back they moved to bigger facilities and hired Chris that is in this video. (A lot of cost involved under several years and no speaker on the market yet..) When the competition is fierce in the loudspeaker arena. Then I hope they will have a differentiation with higher quality and not quantity like the majority of the speakers are. Time will tell..👍

[@nanosochoa3013]

pretty interesting.. PR systems .

[@jepryx]

New subs here

[@swinde]

I have heard the Boz Scaggs track and can easily hear the low note. Does anyone know the fundamental frequency of the note?

[@sudd3660]

im betting its 30hz, its not very low. and still most speakers cant reproduce it properly.

[@swinde]

@@sudd3660 30Hz is actually very low and is only produced as a fundamental on a pipe organ or a grand piano First three keys on the left. The Double Bass (stand up string bass) lowest fundamental note is 42 Hz. I am not sure about an electric bass. Most decent systems can reproduce 42 Hz. Inadequate systems tend to just produce a harmonic.

[@sudd3660]

@@swinde i listen all kinds of music and other content, i cant imagine going back to 30hz rollog point, now that i have heard 16hz reproduced. too much sound content is lost when you dont have full range system.

[@swinde]

@@sudd3660 I agree that a full range reproduction system is better. If you don't mind my asking, what system and components did you hear the 16 Hz playback?

[@sudd3660]

@@swinde monitor audio gold w15 subwoofer.

[@allansh828]

What happens when you hang passive radiators on the walls?

[@qddk9545]

Nothing.

[@Its_Montei]

How low is this note?

[@bujoun76]

Anyone know what a "PR" is?

[@abruptlyblunt]

sadly there are so many things made reference to in this conversation that don't have a visual reference to know what they are talking about like the radiators made out of mdf, that's something which has to be seen to understand....

[@ernestochang1744]

I love my gravastar mars pro, Passive radiators ftw boys i have a spark positive grid ported and the ammount of swoosh and airy floppy bass i get is just ughhh it doesnt sound that good (maybe if i was in a club then yeah) its not balanced, its a small amplifier speaker trying to play huge bass with a small cabinet, theres bound to be some issues

[@azmike1956]

I had some old Sonys with 8" woofers & 8" pr's. Very effective.

[@bartrainer3916]

Are they active radiators?

[@zachariahadams]

I just pump hydrogen into my sealed boxes. Don't worry about the science..... Or the bass level. 🔥

[@swinde]

So if you play it too loud or the amp shorts and there is a spark in the enclosure, and you have not evacuated all of the oxygen from the box. BOOM!

[@zachariahadams]

@@swinde that's the secret to mind blowing bass.

[@jimlloyd1854]

Wow...

[@jimlloyd1854]

Chris is amazing! This topic is one I have grappled with for decades.

[@FeeLtheHertZ]

@@jimlloyd1854 Dude this guys awesome for sure, not douchey, just really chill and passionate. My kinda dude in the audio field. Word up to Chris, for sure.

[@sudd3660]

great explanation, but best way is awaid the whole problem with passive radiators and ports from the get go. not worth the sound quality compromise. build sealed or open baffle.

[@cbrunhaver]

Well, you end up with 3db lower system sensitivity (for a given cutoff and box size) and half the output capability and/or higher distortion in the octave around where the port/PR tuning is, vs a sealed system. Open baffle typically requires 4x the displacement of a sealed system down low and active eq. Not a compromise that most people want.

[@sudd3660]

@@cbrunhaver but a subwoofer fixes all those problems you created for yourself. and a sealed box dont lower sensitivity, only roll off point.

[@bradisley517]

Isn't a PR beside a woofer out of phase with the music?

[@joshdeakins1775]

Probably, but I think ports typically are as well.

[@BastianUllr]

He's speaking about the Buchardt S400 - LOL!

[@cbrunhaver]

No, I was referring to a prototype speaker we are working on. The buchardt speakers are great but don’t have the same extension and output down deep (but are higher sensitivity).

[@roccobruno8027]

I thoroughly enjoy my GoldenEar subwoofers, but speaking of marketing BS "quadratic planar infrasonic radiator" :-)

[@johnsweda2999]

I'm not sure I like MDF floating it's going to have resonance in the MDF radiator at given frequencies, a better solution would be two pieces of hardboard 3mm sandwich corrugated cardboard you can make this with a cardboard box cheap and easily and is very rigid stiff and is very light weight would have to add mass of course for tuning, tell him try that, you can buy good quality corrugated cardboard in all thicknesses, I think is a better process than sticking foam on the back of MDF still going to get resonance the corrugated cardboard will filter out the resonance much better

[@ingenfestbrems]

Guess he kept his job 😁

[@rainbowmat8204]

few years back i use bass radiators but i disappointed

[@finscreenname]

I wonder if you replaced Passive Radiator with a large rubber diaphragm? Don't flame me. Just throwing it out there.

[@jamesplotkin4674]

That would flutter like Saran on the top of your jar of preserves. The PR requires a foam/rubber surround, but the body needs to be rigid.

[@finscreenname]

@@jamesplotkin4674 Rubber can be as thin as saranwrap or as thick as a tire, super taught or loose.

[@SpyderTracks]

Fantastic as always, love you guys! Nice to see you thumbs down and 129 thumbs up!

[@janinapalmer8368]

The effective cone area of aPR should be the same as the bass speaker driving it . The compliance and fundamental resonance Frv of the PR surround should be the same as the driver too. The Qms of the PR should be equal ... all you need to do is run the T/S data of Driver and PR into a professional design program ( I use LMS with LEAP modelling ) The best results are obtained with a driver having a low Vas and Qts ( less than 0.2 say ) This will ensure good transient performance with minimal group delay . The big advantage of a PR is that allows the designer to use as large a port as possible ( which would be highly impractical with the port length ) this large port area ensures a linear port .

[@AlfredJ]

more like middag utan söta jammor!"2#

[@dionysos5337]

kan du ekanske heta en annan namn för den här är lite skojjig för du heter alffred! söta jammorrer🤗

[@AlfredJ]

@@dionysos5337 va

[@dionysos5337]

@@AlfredJ ok

[@Jack96993]

I have a passive radiator in my air cooled Porsche 911SC : ) All kidding aside my Definitive Technology Mythos ST has two passive radiators in it's built in powered sub that helps the speaker go down to 20 hz

[@FeeLtheHertZ]

Funnily enough, Creative Labs, yes the computer speaker company, did some interesting stuff with their SLAM technology - smaller sealed PC subwoofer sized driver powering a bigger PR for the front bass radiation. Super interesting - even IF JUST a PC speaker system! haha. Check it out someday... comment reader, or Paul.

[@clydeblair9622]

No free lunch. Excursion=distortion.

[@FeeLtheHertZ]

TF are you talking about?

[@tom_loves_audio_tech_gaming]

So PR's do not produce bass? euh what... I have the Triton 5 from golden ear... it has 4 PR's. Am into tech and like the design of the speakers.

[@donpayne1040]

^ No. Just did some research, i will not do this. Just have to say "goodbye" to some notes on some tracks, for now.

[@ryanj9235]

19 seconds, oh dear..

[@Paulmcgowanpsaudio]

19 seconds? What's that referring to?

[@ryanj9235]

PS Audio When I clicked on the video it had only been uploaded 19 seconds ago. Your channel is strangely addictive!

[@donpayne1040]

OK, replicate a grubby version of my bookshelves transfer driver and crossover, buy different sized "PR's", cut holes - boom!