Dayton Audio RST28F tweeter | Test and Review 

Dan Saville there may be something inherent in the tweeter design but there is definitely diffraction at play, which is causing most of the issues. The off axis measurements prove it. If you check out my video about diffraction you will see how this can be improved with a round over.

College and years of screwing around. Plus speaker forums in the early 2000s.

Michel Remmel hmm, I might have that one on my shelf. If not next time I make an order I should order a really cheap tweeter like this one for a test video. Good suggestion I’ll keep it in mind. Quite a list of videos ahead of me though.

@@ImpulseAudioSpeakers Thanks for the fast reply! The reason why I want to test this driver is that I'm planning to build a 3 way speaker with it. The other drivers will probably be a Monacor Sp-60/4 and Dayton Sd215-88a. I already designed a crossover for them and they work really well together.

Nowandthenagain hey thanks. I haven’t done a video like that. I don’t think buying those expensive parts are worth it. Especially if you’re starting out, just pass on that stuff.

Most of the time waste of money. If manufacturers use standard parts in kilo $ loudspeakers then why bother. Better use of the money is DSP active crossover and good multichannel amp.

Good Goat in my experience not this bad usually. This tweeter is clearly breaking up above 15khz. Others can usually get beyond 20khz before they have too many problems. I don’t order from PE so the choice was not an availability issue. Another option may be better but this is what we chose so we’ll continue down the path and see how it sounds.

pliedtka I’m not totally blown away by it, but it’s a decent value. I still like the SB better. Even the Vifa XT25BG is better value. Decent sound though.

Arnand de Jager it doesn’t really make much of a difference. The sine sweep I find works better at low frequencies, so I use it when measuring the bass response. White noise (MLS) is said to be better at filtering out ambient noise. I use both but probably prefer sine sweep if I could only have one.

Yep i learned that the hard way when i ordered 4 2" super tweeters and they required a 4" cut out to fit the box....

MrGerson2026 sorry I don’t have that driver.

MrChompenstein the F isn’t bright sounding in my opinion. I wouldn’t worry about that. But I wasn’t blown away by the F so I’d try the A personally. I wouldn’t worry about the Fs difference either. They’re very close I’m sure, so it’s really up to you.

@@ImpulseAudioSpeakers I was already leaning a little towards the A, but once the woofers arrive I can get measurements done on those to perhaps get a better picture of how they behave. Ultimately a waveguide means Dayton's FRD wont be accurate down low, I will just have to take the plunge on one of them. Also, very good info about the off-axis interaction with the dip at 3.5k. I will be sure to look out for that. Thanks

who cares I did the SB29RDCN if it interests you. I like it a little more because it’s almost the same performance but the neo allows for a really small faceplate therefore closer spacing to the mid or woofer. Check it out :)

pliedtka I agree with the wider baffle. Hopefully I can find to do that. The 4ohm thing I’m sure is just to spec brag that they can do 93db or what ever. These didn’t even make the sensitivity spec. So not that impressive really. In the end they usually always need padding down but in that rare circumstance that the rest of the drivers in the speaker are that sensitive then these 4ohm tweeters have a better chance of marching.

pliedtka I haven’t had a chance to look at Vance’s testing yet. Good reminder though. I’ll try and do that tomorrow.

Manuel Muresan I didn’t think of that. Mine is not controllable. I’ve never had this problem to be honest. I don’t think it’s a particularly hot iron. Oh well.

Steen Suder I have a little bit of use with the ND20 and a lot of use with the ND28. The little ones have to cross pretty high and that’s their downfall. Otherwise ya they are good for having very close spacing (thus less lobing) and are cheap enough to experiment with. I’m a cross low and cover as much of the 2,000-20,000 Hz range as possible kind of guy so the little NDs haven’t appealed to me much personally.

@@ImpulseAudioSpeakers Thanks, the idea here involves the new SB MD60N-6 (currently for preordering) and crossing at 5 or 6K (3 way). I'm trying to find out if they're good enough in the top two octaves to spend time on experimenting. Little diameter could cater for wide dispersion and the high cross would minimize the impact of the low power capability. FYI, the MD60N-6 is preorder priced at ~€15 in Europe which makes it very interesting in my eyes.

Рубаиль Сафаров I’m not totally sure what you mean the dynamics. Do you mean distortion? I use Xsim to load the frd and zma files to play with crossover components. There are other options but I find this to be the easiest and best.

@@ImpulseAudioSpeakers How can I measure the frequency response myself and save as FRD and ZMA, through a microphone or through some kind of program?

@@ImpulseAudioSpeakers in short, I need to measure my speaker and put it into the XSIM program, but how?

@@ImpulseAudioSpeakers I mean to DRIVER

@@ImpulseAudioSpeakers How to get FRD and ZMA?

Frank Geiger hi. The combination isn’t a bad choice. Using drivers that are better suited to roles as woofers and mids would be better. Also, no need to match brands. Usually doesn’t look as good as people think and has no impact on sound quality. Better to pick drivers that make sense. But most important, as a beginner, please do a 2-way. 3-way speaker’s are 3x harder to do and you chances of success and satisfaction with the process will be so much higher with a 2-way. Sucks to spend $300 on parts and get mediocre results and wish you just bought speakers. Even if you want a 3 way, do the 2 way first. Honest.

@@ImpulseAudioSpeakers That´s the difficult one: how do i recognize drivers which are suited for my project? I´m not set on dayton speakers, so what are your suggestions? Personally i would prefer a 2-way system but because of the special situation for center speakers that seems to be quite difficult......

Frank Geiger ah, a 3 way center channel speaker. Even trickier. How about a design already published that you can follow along? If choosing the drivers is new to you, then crossover design will be too. If you pick a design that’s already worked out you’ll be more likely to succeed and learn a lot along the way. If you do want to have a go at it, then I’d use those Dayton drivers you mentioned cause they could be repurposed many ways. They’re jack of all trades drivers.

@@ImpulseAudioSpeakers I wanted to build a 2-way-system using the mentioned tweeter and woofer, but then i learned that most centers are actually 2,5-way systems to avoid the drawbacks of an d´appolito-arrangement of the drivers, but they have - spoiler-alert - disadvantages by themself. I actually looked for an already published project but i could´nt find a speaker which is max 8 inches high, better 7 inches......

Yes

Shaun Onverwacht ya a push on terminal would negate that issue. I’ve never had this problem with any other tweeter though. People solder onto terminals like this all the time. Not sure why these would be so sensitive to heat.

@@ImpulseAudioSpeakers yes, traditionally they were usually solderable.

I actually accidentally melted the terminal right off on my first build. Luckily I managed to solder directly to the voice coil leads they were attached to and it still worked fine. But yeah the plastic gets super soft super quickly.

@@__-fm5qv Old school method is to clamp a long nose pliers between the solder joint and the (temperature) sensitive part. Acts like a heat sink.

Hmm, maybe around 2khz depending on how it is done. Possibly lower. Also depends on the application. If you are using them for desktop speakers or background music, then 1500hz is probably ok.

@@ImpulseAudioSpeakers I was going start it hard at 2000 with a 3 rd order crossover and an Lap and it's going to cross the woofer at 1500 and the woofer I'm using a 3 rd order also so they are both dropped off really fast. But some people are telling me that the old rts28: was better and the new is just ok idk I never used either. But they are for my small bedroom for my TV and music it's like 10" from couch where I sit and watch TV and listen to music it's a small room around 12" 16" but I was pairing them with 8" Dayton audio reference paper cone they don't break up as made as the aluminum. I'm dropping the woofer at 1000 with a 3rd order and the tweeter at 2000 with a third order and a L pad and they are both dropped really hard so I think I should be ok . I designed it on xsim. They are going to get played loud sometimes with heavy metal so hopefully they can take it. Thanks again and are making videos anymore?

Илья Основиков yes that could help but introduces other issues. The best is to roundover or chamfer the edges, which I’ll do in the final build. Edge is an excellent tool. Xsim also has a diffraction predictor if I recall correctly. They’re very useful.

@@ImpulseAudioSpeakers Agree, but at those frequencies (3500 Hz) a roundover or a chamfer has to be faily large in size to be effective. Am I correct?

Илья Основиков yes that’s true. At least 3/4” would be good. I’ll be able to get an inch, maybe more on the final build.

What other issues?

ThePentosin the other issues is that it only corrects the diffraction for one axis. As you move off axis it shows up again. Basically sharp baffle edges have diffraction no matter where the driver is on the baffle. A big round over actually reduces diffraction. The offset just moves the diffraction frequencies around a little.

joppe peelen I’m not sure what you’re asking. What is weird about the measurement? THD is the total distortion of all the harmonics (2 to 5) added up.

machoheadgames I haven’t seen any other tests but I thought this looked really good. Other than second order, the other orders are way down in the floor. Level was set for equivalent of 92db at 1m so I left the 2.8V input. Moved the mic to 10cm. It’s really hard to compare distortion tests which is why I rarely talk about them. I usually just throw the results on the screen and tell people to go back and pause to look. This time I spent more time on it because I’ll be working out a XO. So depending on how different they look I wouldn’t be concerned. This was a good results and out of all the tests done here it’s what makes this tweeter ok, unlike the frequency response.

The only other test of RST28 was done by Vance for Voice Coil or Speaker Builder, unless there is a test which Google search doesn't know about

pliedtka oh I’ll have to check it out. Been a while since I checked my voice coil account. I missed it.

Hey, let us know what's different between your review and Vance's, other than infinite baffle in Voice Coil test - other than that they should be quite similar, unless there are production variances like in RS midwoofs you tested.

hificompass.com/en/speakers/measurements Very good, infinite baffle measurements

juanmangerita to me it sounds ok. I have other videos about using this tweeter and make some comments about it. It’s really hard to make subjective comments about a driver because it depends how it’s used. If I implement it poorly or match it with a really good mid etc I may have a different opinion. A complete speaker is a finished product that subjective comments can be made about. Even then it’s important to make sure it’s implemented into the room and system properly. But these variables, although huge, are much smaller than a raw driver.

Tarek Z I will be adding round overs to the finished speaker and may test on a 200mm baffle with a round over. Foam isn’t a very practical form of diffraction control in my experience. Hopefully the finished product will control diffraction better when I’m done.

Maybe move the tweeter over to one side abit? Edit: this is already brought up in another comment.

ThePentosin ya as mentioned with the other comment you saw, it helps but not a ton. I’ll use big round overs to try and help with that.

Raymond Cooke all good points. One, I normally rotate the little stand on top but didn’t this time. Which is why I poked fun at myself during that part. Two, ignoring it is paying attention to the listening window. Much the same as the coax or waveguide example. I know that the listening window will be fairly smooth through there. Especially after I explain number three. But maybe I’m not quite understanding what you mean by this?? Three, I do plan on shaping the baffle. This was just a test box and will go in the garbage once I’m done with it. The final box will include hand shaped round overs. That will really smooth out the off axis response and make the listening window more uniform. Definitely good things to think about and happy to see viewers paying attention to those details.

@@ImpulseAudioSpeakers Thanks for the detailed reply! I missed that you were going to smooth out the edges on the final cabinet - though why roundovers when your tests showed chamfers worked just about as well? Aesthetic preference? I thought this box was the same form as your final one, and was thinking about earlier studies - David Ralph's for example - that showed how using felt or foam strips on the baffle can reduce diffraction effects.

Raymond Cooke mostly how I want the final aesthetics to be. It’ll make more sense once they’re built. Hard to explain. David’s work is the best I’ve seen with the felt. I haven’t personally done much testing with felt so I shouldn’t make strong arguments for or against it. I think it has merit but man it’s ugly haha.

Never had an issue before. I prefer the security of solder. Both work though.

Shane Fage ya I agree. It made the driver feel very cheap. All 4 did it.

I agree. I'm out.

@@ImpulseAudioSpeakers I have had a couple of my own reviews of the precision devices drivers published in the last 2 days. I wrote in a very different language than is normally associated with loudspeaker design... of course, on purpose. PD published my reviews and so did Chris over at Solen.

I've lived in both Indiana and Colorado, no L pronounced in either place. It's a regional thing I think. Funny thing is, I have never heard anyone pronounce the B in plumbing while they are talking about soLdering the plumbing parts together.

John sweda not sponsored. I paid for these drivers myself. I don’t use Dayton very often but they do offer good value. I generally prefer SB Acoustic for this price range though.

SB Acoustics, Seas domes, and possibly Beyma amt drivers.

Whoa there. You went from really good bang for your buck to "Holy Shit this amazing tweeter is expensive"

Yes, the Beymas are expensive but they also make a Q$200 amt tweater but it doesn't cross as low and the power handling is not there. I should have also added peerless (vifa) tweeters as well because they do have some good value propositions. I should say that seas does make some good $50-70 tweeters that can compete with the sb acoustics.

George Zubeck the peerless stuff is quite good. They deserve more attention. In the 90s vifa is all people used and they’ve slowly taken a back seat.