Speakers for a child!

[technodanvan]

Good morning! I'm starting to plan out a set of speakers for my goddaughter (and her older sister) as they get older. Average age of the two of them is like....4 years old right now. Probably won't start on these for a bit yet, but I want to start collecting parts and watching for sales and stuff. Stuff to consider below:

• Cost is not really a factor, but these are for a child and placement would most likely be up against a wall on a dresser or something, so our hifi target is somewhat constrained.
• Everything should have a grille to protect the drivers, probably metal, and something that isn't immediately removable.
• I don't believe paper drivers would be appropriate as they'd be less durable if a finger did get through the grille somehow? Open to thoughts on that.
• Having power and Bluetooth integrated may be nice. Discussing this with her dad...may need a way to get TV audio through them too.

My initial thought was to use a coaxial driver I already have (I have a few from Sica, Seas, and Tang Band) but that would necessitate a custom grille. So I started browsing (a dangerous endeavor) and tentatively identified a driver not named Accuton with an integrated grille that may be worth working around, the Tang Band W3-1797S: https://www.parts-express.com/Tang-B...888?quantity=1.



I have also considered looking at car audio 6 1/2" coaxials as they almost always come with grilles. Something from Focal maybe?

Open to thoughts and ideas!

[Scareurpasenger]

I think I saw some magnetic grills like the ones above for sb acoustics drivers.

[technodanvan]

Hmm, I have found some that are indeed magnetic but use soft fabric instead of metal. Any chance you could dig up a link to where you found that? I know there are generic ones too.

I do have to wonder if magnets would be strong enough though.

[technodanvan]

I guess this is technically a possibility. Kind of out there in price though considering I'd mostly just be paying for the protection.

https://www.madisoundspeakerstore.co...amic-mid/bass/

[technodanvan]

That's fair, but we're talking about very young people here, at least initially. I'll ask about where these might specifically go, maybe they'd be out of reach anyway. I'm also hoping these would at least last through her teens, if not college and beyond, if she wants, so I'm okay with spending some cash for something that would be around for 10-15+ years.

[technodanvan]

I also considered going in a different direction entirely - get relatively inexpensive drivers that could be swapped out in a few years if they get damaged. I'd still get a tweeter with protection I think, but a woofer like the RS180 or the SB ceramic line could fit the bill.

[JonMarsh]

This is a good price for this driver, but it is a bit tricky to work with due to the relatively high Q breakup mode that boosts the distortion down around 1kHz due mainly to resonance amplification of distortion products. But I do agree they're pretty kid proof...

[Scareurpasenger]

Hmm, I have found some that are indeed magnetic but use soft fabric instead of metal. Any chance you could dig up a link to where you found that? I know there are generic ones too.

I do have to wonder if magnets would be strong enough though.

They are fabric and I must have been remembering some of the other options from here. The Monacor grills look to be universal and are on clearance. https://en.toutlehautparleur.com/lou...tive-grid.html

[technodanvan]

I might have the tweeter covered already, I have several Dayton RS28A sitting (somewhere) in storage right now with no major plans for any of them. They seem to come with a metal grille attached. I'm sure it's not particularly durable if someone had intent to damage, but it's probably sufficient for a child. The only other tweeters I have with grilles, at least that are not currently earmarked for a project, are beryllium domes from SB Acoustics. Probably not ideal.

Given the number of designs out there using the original RS28A I suppose I could just use one of those. The RS series woofers are certainly pretty nice, reasonably priced, and have solid phase plugs instead of a cone dust cover that could be pressed in. I suppose that is the best path forward.

I still kinda want that Tang Band 3" and the Accuton previously listed though.

Edit: Since my application probably puts these up against a wall, I suppose using a proven design might not be ideal. I could go with the Modula MT or Natalie P though, seeing as how the designer is still here and could offer some advice on baffle step reduction.

[Scareurpasenger]

I just finished the rs150mt with an Rs28a and there is a low/no bsc version. I still need to measure them though.

[technodanvan]

Oh yeah, I came across your thread again today in my searches. What sort of bass are you getting out of them? Pretty satisfying for the size?

Edit: I'd need to modify somewhat for the port to not be on the back, but I think these might be a great starting point!

[technodanvan]

This is a good price for this driver, but it is a bit tricky to work with due to the relatively high Q breakup mode that boosts the distortion down around 1kHz due mainly to resonance amplification of distortion products. But I do agree they're pretty kid proof...

Jon, how can you tell the higher 3rd order distortion at ~1kHz is due to resonance amplification? Is that generally inherent when seeing a 'blip' in distortion sweeps, as opposed to seeing gradual rising distortion over several octaves?

Edit: Disregarding the need to be childproof and evaluating the Accuton purely on its merits, is it even a decent value as a midwoofer? While a bit less expensive than several Purifi drivers of the same diameter, I would have to think the newer Purifis would be a better value.

[JonMarsh]

Jon, how can you tell the higher 3rd order distortion at ~1kHz is due to resonance amplification? Is that generally inherent when seeing a 'blip' in distortion sweeps, as opposed to seeing gradual rising distortion over several octaves?

Edit: Disregarding the need to be childproof and evaluating the Accuton purely on its merits, is it even a decent value as a midwoofer? While a bit less expensive than several Purifi drivers of the same diameter, I would have to think the newer Purifis would be a better value.

It's diagnostic due to frequency multiples. This is something I used to be looking at with drivers WAY back, early 2000's, you know, NatalieP days. This is also when I started working with high Q notch and elliptical filters, and looking at the influence of crossovers on distortion.

In the old days, there were a lot of MTM's made with RS180's and the RS28a tweeter. I never saw a crossover for another version that did notch filter isolation of the breakup modes. The reason is reduces distortion on lower frequency signals, like 3x lower for HD3, is that it literally decouples the driver motor generator impedance at the distortion frequencies, due to the impedance rise. The notch additional attenuation of the break up mode in the transfer function doesn't hurt, either, but it's the alteration of the driver effective generator impedance loop at those frequencies that makes the difference. Can't do that with DSP, folks...