Ported TWEETER?! (No, this isn't clickbait.)

[@ErinsAudioCorner]

Generic Affiliate Links to use while shopping: Amazon: amzn.to/3v6i6ov Audio Advice: www.audioadvice.com/?referral=erins-audio-corner&b=3 Crutchfield: shop-links.co/cgZmmT81jmh ^ any purchases you make using these helps earn me a small commission at no additional cost to you.

[@AbsoluteFidelity]

We need more designs like this that solve problems instead of creating some. Bravo to Alex, hope he perfects it!

[@ErinsAudioCorner]

You and me both!

[@AbsoluteFidelity]

@Douglas Blake so?

[@ErinsAudioCorner]

@Douglas Blake I think you’re missing the point here. This is no different than a horn-loaded design. An appropriate crossover corrects the peak while allowing headroom which enables a lower crossover point.

[@AbsoluteFidelity]

@Douglas Blake reading comprehension 101. Does 'hope he perfects it' ring any bell? And its how its all about how its going to be implemented ultimately, its not like its a hard thing to fix. As with anything, nothing is perfect and there will always be give and take. You are dissing this way too early.

[@IliyaOsnovikov]

I believe that a waveguige would not only boost the low end response but also would narrow a tweeter radiation pattern in order to better match it off-axis with a midrange/midwoofer.

[@ErinsAudioCorner]

Yes. But I was talking more about the horn loading and effect here. 👍

[@jyrkih6960]

Or is it the same thing: Radiation pattern is narrowed, hence more sound energy projected forward.

[@falxonPSN]

I definitely would like to see more interesting innovations like this. This is pretty damn cool!

[@ActuallySettle]

Like many great ideas it seems incredibly obvious in retrospect. One wonders if it could be combined with a waveguide. Fun to think about.

[@j777]

Glad you mentioned headroom, cause I was thinking it was a good fit for the headroom you need for actual music, which tilts down

[@derekjarman1638]

What a cool idea - especially for the car 👍👍

[@pike3685]

Japanese manufacturers from the 1970s-1980s I wish you would measure…diatone, victor, onkyo, technics, Sony, these may be some of the best ever produced and are slept on. I’d be very curious what someone with your expertise figured out with these speakers.

[@jcadlols]

I feel like you could add Yamaha to that list. Some beryllium NSs would be very cool to see detailed measurements on.

[@ErinsAudioCorner]

I've tried to hunt down some older designs. Particularly the Yamaha NS-10. Can't find a loaner set in good condition.

[@TadghsMuffins]

Yo idk about anyone else but this video is of huge interest for me, I design speakers a lot and spend a lot of time playing with designs that rely on really low xo - I'd buy a prototype to use if he let me :D

[@MIKEDIAMONDZ]

I like the way you build speakera and you tune them to a specify request ...solving the car problem in this episode was good. If you can make the a video about how to make a good cabinet, and where to get good drivers for it

[@danielduesentriebjunior]

Electro Voice used ported midrange drivers in the 1980's in the Interface Gamma and Delta models.

[@RennieAsh]

It seems that Morduant Short may have used some sort of "ported" tweeter arrangement on their Mezzo speakers or around that time. "Aspirated" I think they call it. Different goal perhaps.

[@tonfeile1561]

Wow, great idea and really well tuned for a prototype. Looks like a ScanSpeak. Is it possible that the THD difference at 7kHz is caused by the lambda/2 port reso? The video is already two years old, but I haven't heard anything about a market-ready product. That would be sad. Many thanks for the video and greetings from Bavaria

[@vortexan9804]

EV made a ported mid used in some pro cabs as well as large home speakers in the 70's. It features the same magnet and VC size as the SP and EVM woofers. Amazing, powerful units, I have a pair.

[@jked7463]

My understanding is that the reason tweeters are not ported is because of the phase issues. Also the sudden shift in phase at the ports would probably cause clarity issues in the frequency area of the port. At the extreme low Frequency of a ported woofer with the long wavelengths, the loss in clarity is not as noticable. But even non-ported woofers sound cleaner, maybe less low bass but clearer.

[@alexralph9929]

Tried to reply earlier, but comment disappeared. Sorry if this appears twice. The phase change around tuning frequency is gradual. This is reflected in the group delay measurement at the end of the video. The is also "port resonance" which appears at a higher frequency. It is related to the length of the port, and in big subwoofers will show up around 200Hz. It is a sudden shift, and screws with the frequency response. If the length of the port is less than 9mm (as in the tweeter), then the port resonance is kept above 20KHz.

[@jked7463]

@@alexralph9929 I beg to differ. The phase change at the port is anything but gradual. It is a 180 degree flip in a fraction of an octave. At the high frequency of this port, it is very fast, steep and sudden. I am not talking about group delay, I am talking about phase shift. You can have phase shift with out delay but you can't have delay with out phase shift. Additionally, as stated in the video, ported speakers exhibit higher distortion below port frequencies. Add in the difficulty if trying to get a smooth crossover due to shifting port phase in top of crossover phase shift and is there any wonder why other tweeter designers used large back chambers and tapered tubes, but not ports? EV tried porting their midranges back in the 70 (?) But it didn't last and no one followed suit. There has to be a reason they didn't. My guess is for the same reasons. The basic physics of speakers was known +/- 100 years ago The big improvement that have been made since then have been in material sciences, not basic physics.

[@alexralph9929]

@@jked7463 If you look at the frequency response (6.17), you will see that the ports are contributing to the output from around 950Hz. This means the air coming out of them is starting to be in phase with the diaphragm. The air gradually changes phase until around 1400Hz (maximum boost), when it is in total phase with the diaphragm. Beyond that, the mass of the air in the ports starts to reduce the ports output (can't change direction fast enough). Below 950Hz, the output from the ports is gradually becoming more "out of phase" with the diaphragm. This is the reason for the steeper roll-off from a ported speaker. Eventually it is 180 degrees out of phase as you said, but I would call that change gradual. If there were any fast 180 degree shifts, they would show up as major dips in the frequency response. This does happen at the "port resonance" frequency though. Erin has graphs on his website that show this. He has measured some subs with the port open, and closed. The port resonance is obvious. As for EV, I can't imagine they released a product into the market place that didn't work. They were heavily invested in research and had some excellent products. My best guess would be that it was not necessary. The midrange was 6 1/2 inch. It doesn't need help from a port to cross over from a 15" woofer (piston range to around 350Hz). A port would also make the passive cross-over a little harder to get right.

[@alexralph9929]

@@jked7463 I'm happy to discuss , but please reply in a new message instead of editing an old one, it makes things difficult for others to understand. As I mentioned, any fast, steep or sudden 180 degree phase shifts will show on the frequency response as a sudden dip, it cannot be any other way.

[@jked7463]

Sorry about the corrections after the fact, but they are corrections and I did not want to leave the original post incorrect, or at least not clear.

[@arvidbjerre30]

Great video as always, thanks Erin! Interesting choice to port a tweeter. But I don’t understand how extending the low end response of a dynamic driver with the help of a resonating air volume and a port is something that can be granted a patent.

[@PoisonStore]

Yea.. scanspeak had tetcnology called aircirc it is quite the same thing.

[@alexralph9929]

Yeah.... Nah. Nothing like it.

[@PoisonStore]

@@alexralph9929 or maybe it is sealed... since the purpose of the chamber is to circulate the air inside to be evenly distributed. No vent then? Is this correct for the air circ?

[@alexralph9929]

@@PoisonStore Yes, it seems to be for controlling standing waves in the rear chamber.

[@FOH3663]

Most any resonant alignment, brings untidy time domain challenges, right? It's the classic conundrum right? One always has to weigh; elevated output at a given distortion level vs; less than ideal time domain performance Down in the LF, the same challenges exist. But in use, the subjective hit is lessened perceptually in the lower octaves. The question would be, what does the listener experience when those resonant behaviors are placed right into the mid-band octaves? The attributes are always welcome (headroom, etc.), but how would those time based issues impact the playback? Smear sounstage details? Shift image fore or aft? Dipole aside, it would seem the direction tweeter/loudspeaker designers have settled upon pursuing is a sealed, controlled dissipation of backwave energy, many into a tapered tube like approach. Erin thanks for bringing this to our attention, very cool... always thought provoking solid work. (this illustrates how driver/loudspeaker design is a pure balance of compromises, an ever fascinating multi-disciplinary pursuit... one can't simply bulldoze forward with money following a single best approach)

[@redrobbosworkshop]

Interesting design. I've long felt that most conventional tweeters are not properly capable of crossing to typical 5-8" mid woofers because they just aren't great running at a low crossover point. Love your work btw and followed since day 1. Just subscribed on Patreon.

[@vortexan9804]

Some soft dome tweeters with back chamber can go low enough. If not, you can use a 1.25 or 1.5 in.dome.

[@alexralph9929]

@@vortexan9804 Some tweeters with large Xmax can be crossed lower, but you have to be very careful with how much power you feed them. Also expensive, they generally need a big neodymium magnet for the large Xmax. Bigger domes will have reduced dispersion at higher frequencies, and if you ported them, they could be crossed even lower.

[@ErinsAudioCorner]

Wow! Thanks for the support. Yes, very interesting design. Stuff like this is really cool and I was happy to bring a bit of light to it.

[@Chase1297]

@@alexralph9929 do you have any larger tweeters capable of low xover you’d recommend 👀

[@alexralph9929]

@@Chase1297 Short answer - as Frank mentioned in the comments, Wavecor and Peerless have some good value tweeters with large excursion (not a recommendation, I haven't heard/played with them). Long answer - excursion and power handling are the 2 limiting factors. The free WinISD software lets you model a tweeter (some software won't cover high frequencies). Wavecore has excellent data on their drivers that you can use as a starting point. This will show you the excursion and power handling you will need for your design goals (crossover point and SPL). Typically tweeters have underhung voice-coils that will distort quickly when pushed beyond Xmax, so leave yourself some headroom. The more affordable tweeters will use a ferrite magnet. The tweeter in the video has a 2mm voice-coil gap height, with 1.4 Tesla magnetic field. When we increase the gap height (for more excursion) you reduce the field strength, which reduces the sensitivity. You also need to increase the gap width for larger excursion in order to avoid any rubbing of the voice-coil, which also reduces the field strength. This can be offset with a wider magnet, but comes at a price (money, weight, and size). To keep it small and lightweight the best tweeters use Neodymium ring magnets, but they are expensive. Bliesma have tweeters with 1.5mm travel, and a saturated motor (probably around 1.8 Tesla in the gap). There's also Morel and others. 👍

[@ryanchappell5962]

Yeah this is cool 😎

[@MyTgangsta]

Nice reading the patent didn't really show much but I got what he's doing know for me to experiment on some tweeters and see if I can make them play lower with my add on idea so wish me luck

[@aaronmatuszny8856]

I imagine a bliesma tweeter (with 2mm Xmax) would be just bonkers as a ported design. Add in a wave guide, and you might not need midranges ever again!

[@Clobercow1]

Okay... Lets horn load this ported tweeter... That would be neat.

[@BuriedAudioUK]

As cool as this is, there are quite a few issues with ported tweeters, they have existed but the majority of them died at the prototype stage. The steeper roll of is undesirable when designing passive crossovers, the complexity of production at scale has been for a long time, to much. Hopefully with these issues fixed it can become a useful tool, for us designers.

[@diymaster1121]

If you are still doing driver reviews would you be willing to review the very famous tangband w5 subwoofer ?

[@johnbeeck2540]

Very good explanation Erin!

[@BLOWNGS]

A waveguide version would be a beast.

[@vesalaasanen2158]

I really enjoy this type of content! Also would love to see more affiliate links towards us on the other side of the pond. Maybe Thomann?

[@ErinsAudioCorner]

I hadn't even considered that. I will look into seeing what kind of affiliates make sense for me but I generally try to stay with something I have personal experience with.

[@katebloggs8243]

It appears Thomann sells in the US as well, and they have good-looking prices on Genelec, so it might be a good cross-pond link?

[@kirkstarson]

Now you've made me feel like I'm on the cutting edge! Hehehe

[@abdo-dr1tu]

It's as if someone made a tweeter just to match the 8-inch purifi without making an 8-inch waveguide.

[@ErinsAudioCorner]

🙃

[@RennieAsh]

There was that bliesma 34mm tweeter

[@markdiaz976]

How are 1723 aredal towers and center channel

[@Sol7Studios]

Ever tested ATC Monitors? SCM25A’s or other ATC speakers?

[@ErinsAudioCorner]

Not yet.

[@lancebartlett3892]

What's it called and where do you buy it?

[@Bradimus1]

If you spend your time doing stuff that's interesting to you, it's probably going to be interesting to the majority of your subscribers. And probably original content.

[@ErinsAudioCorner]

Very true. All this stuff is interesting to me but some stuff is definitely more intriguing. Like this little tweeter. 😀

[@Audio_Simon]

When do I get a passive ring radiator tweeter?

[@ErinsAudioCorner]

Alex would have to answer that. 😂

[@alexralph9929]

Did have a play with it years ago, but thought production would be a bit tricky ($$$). Just focused on ports after that.

[@catherinelugg4321]

Very cool discussion. Thanks!

[@ErinsAudioCorner]

Glad you enjoyed it!

[@catherinelugg4321]

@@ErinsAudioCorner Yeah, I was like WUT????? But you did a great job of explaining how it's a true ported tweeter. Let's see if you get a call from Bentley. LOL!

[@ErinsAudioCorner]

@@catherinelugg4321 LOL. I’m gonna charge them a finder’s fee. 😂😂

[@rhalfik]

Ok... How do I put this is a waveguide?

[@alexralph9929]

Just extend the ports into the waveguide. Have to keep them short to avoid port resonance, so the waveguide can't be too deep.

[@vortexan9804]

I see too many phasing problems doing this, wont get a flat response.

[@alexralph9929]

@@vortexan9804 It works, made prototypes. The biggest issue is getting the shape of the waveguide correct for the diaphragm, but that's with or without the ports. Getting it wrong will screw up the frequency response.

[@mhnoni]

Hi Erin, I asked a question on the Klipsch but you might missed it since there are a lot of comments there, Anyway, which speaker you will advise me to get if the vocal is the main thing I care? RP-500M II, RP-600M II, Polk r100, or Kali Audio IN-5? I mostly use it with my PC as a nearfield.

[@ErinsAudioCorner]

The Kali is the most neutral of the bunch. I’d look at that or the Klipsch 500m II depending on placement and size.

[@mhnoni]

@@ErinsAudioCorner The Kali has a big raise at high frequency in the graph you measured, is that going to be a big problem and make the speaker bright? or it's very far away from the human hearing to be a problem?

[@ErinsAudioCorner]

@@mhnoni ​ the peak being high in frequency of the Kali may not be as bad as one would think. However, what I encourage you to do is to try both the Kali and the Klipsch and see what you think. Make sure to take time aiming them in different ways (on and off-axis). Then send back the one you don't want to keep. If you can.

[@mhnoni]

@@ErinsAudioCorner Thanks a lot Erin for taking the time and answering our question.

[@harryburnett7086]

Erin you should start designing speakers just saying

[@JeffAdairKTM530]

Love you - thank you for sharing this

[@colbylaro9361]

Did you happen to install it with a woofer and listen to what it actually sounds like? 🤔

[@ErinsAudioCorner]

No. I've talked about why in my driver reviews.

[@colbylaro9361]

@@ErinsAudioCorner but what if I sounds like a kazoo?

[@ErinsAudioCorner]

@@colbylaro9361 it's probably because you're playing kazoo music, then.

[@colbylaro9361]

@@ErinsAudioCorner oh..that's a really accurate tweeter.

[@cwctw]

Do you hear port noise?

[@ErinsAudioCorner]

No.

[@pliedtka]

LOL

[@hoth2112]

Interesting.. this makes me wonder if adding a rear resonance chamber will help to reduce it's FS, drop the peak a bit, while also increasing its low end extension? I say this only because if this were a woofer's response in a ported box, it would suggest that the bottom-end bump followed by an early roll-off means that the airspace used is too small for the driver. It would be interesting to see what will become of this design as things progress.

[@alexralph9929]

Yes, Premium Sound Solutions have a design just like that, and it works as you described. The back chamber works like a miniature bass trap, but it does cause a slight increase in diaphragm travel. With this design, the ports reduce the diaphragm travel. The bottom end bump is necessary so you can reduce the power fed to it through the crossover. The power and diaphragm travel are the main 2 limitations when feeding a tweeter lower frequencies.

[@vortexan9804]

Nothing new with back chambers, been around over 20 yrs.

[@hoth2112]

@@vortexan9804 that's why I mentioned it as an option.

[@nagumaninagu9368]

Today recharge. Miss video.

[@montynorth3009]

This patented ported design will be of little sonic value, but it might add marketting value to a speaker that uses it. As stated in the video,the lower crossover frequencies can cause the destruction of the tweeter, and the same will apply here as extra wattage will be assigned to it.

[@alexralph9929]

Actually the opposite. The 9dB of gain means it's fed much less power for the same SPL, and the tuning reduces diaphragm travel. These are the 2 things that would damage a standard tweeter.

[@abdo-dr1tu]

@@alexralph9929 The increase in excursing below the port tuning frequency should also be considered, so you would want steep crossover filters (generally a good thing imo). the group delay could be audible, which might need some FIR massaging.

[@alexralph9929]

@@abdo-dr1tu Yeah, it really needs minimum 18dB crossover to deal with the travel increase below tuning. Group delay OK, haven't heard any issues. The research I've seen says 1-2m/s before audible.

[@abdo-dr1tu]

@@alexralph9929 the ported tweeter has 5ms already, with a steep crossover that is likely to increase.

[@alexralph9929]

@@abdo-dr1tu The measurement isn't at 0. Both sealed and ported base-line at 4.2ms. At 1500Hz, the sealed is around 4.4ms, and the ported is 4.9ms. So when zeroed, the sealed is .2ms (pretty standard), and the ported is .7ms (not perfect, but below audible)

[@boohoo5419]

erins clkickbait corner..

[@gitech7450]

Ur' likely to find my cool stuff and share it with the world someday bud ;)

[@trevorm574]

ASR boycotts you I boycott them. You rock. Keep up the great work!! Cheers

[@emuclone154]

I haven't seen anyone on asr boycott Erin. 😕

[@ErinsAudioCorner]

Not that I'm encouraging a boycott, but I do appreciate the kind words. Hope you found the video to be fun and interesting!

[@ChicagoRob2]

ASR is useless. They listen to measurements, not music.

[@kristiankeller4335]

I spend waaaay to much time on ASR, but I wouldn't dream of boycotting Erin. Love his videos. Have no convictions about audio that makes me want to become political.

[@LynnXternal]

ASR isn't useless; I've run into a lot of cool people there and the site was founded as an alternative to the science-lacking communities around audio gear. That being said, it's very much an "old boy's club" and veering out of the technical threads, some of the users there become unpleasant to share a space with.

[@frankverschoof8083]

Due to the IAD effect (inter-aural amplitude difference) between 700 and 1400, it is very helpful if a tweeter could be crossed at 1k (Wilson audio: 1200). Waveguides help a lot, but this might be push we need. en.wikipedia.org/wiki/Interaural_time_difference

[@alexralph9929]

Totally, you know you stuff 👍

[@frankverschoof8083]

@@alexralph9929 Just a bit... Audio is pretty much my life for 40 years, but i've heard of this (well recorded) effect only a few years ago. Completely changed my approach on loudspeaker design.

[@alexralph9929]

@@frankverschoof8083 Hard to get 1 driver to cover such a big range, but great if you can. In another life I worked with EV Sentry 500 speakers. They had a large dome tweeter in a big waveguide, crossed over @1500Hz. Sounded quite different to any Hi-Fi speakers of the day, very accurate. Didn't know it at the time, but I think IAD had a lot to do with it.

[@frankverschoof8083]

@@alexralph9929 Loved de 500, still use them from time to time. They work very well in big conference rooms. I blew out a tweeter once and replaced it with the Audax TW034 (both channels). Definition was a lot better btw. There are OEM's who work in a very broad range: Devialet uses a 2" dome from 800 up to 20k. The old 3way designs with a 2 or 3" mid dome make more sense now. A candidate for 1k might be the Wavecor TW030WA12, or the Peerless DA32TX00.

[@alexralph9929]

@@frankverschoof8083 The Peerless is impressive. 1mm travel at a decent price👍.