Hello, I consider building a couple of small, around 6" x 6" x 16", bluetooth speakers as a way to use up short boards of nice wood accumulated in my cutoffs bin. However, having never built a speaker, not sure if it is possible to diy a reasonably sounding speaker with parts from online stores as suggested in many youtube videos.
I could work out crossover designs for specific woofers and tweeters combinations, but, Is bass reflex even worth trying in such small volumes, around 0.23 cu ft? And what is practical lowest frequency to aim for if calculating bass reflex? Would making them stereo be unnecessary due to small size?
Any answer/comment would be gladly accepted.
Thanks, h.
I could work out crossover designs for specific woofers and tweeters combinations, but, Is bass reflex even worth trying in such small volumes, around 0.23 cu ft? And what is practical lowest frequency to aim for if calculating bass reflex? Would making them stereo be unnecessary due to small size?
Any answer/comment would be gladly accepted.
Thanks, h.
If the enclosure size must be similarly small, you cannot compete with bass output of commercial bluetooth speakers. They use some DSP tricks that are not available to an average DIY person, like level dependent bass boost or bass enhancement by creating harmonics to suggest a non-existent fundamental frequency. Most of them use a passive radiator as ports do not fit. A lower cut-off of 70 Hz is sufficient. See this website for some measurements: Oluv's Gadgets
6" x 6" x 16" is quite large so it is much easier to get some bass out of it.
6" x 6" x 16" is quite large so it is much easier to get some bass out of it.
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They say that the displacement of the passive radiator has to be 2x that of the woofer. The displacement is Sd x Xmax, right?
Is it true then that a passive radiator with Sd = 50 sq.cm. and Xmax = 8 mm would be sufficient for a woofer with the same Sd and Xmax = 4 mm?
Essentially, it means that the diameter of the passive radiator can be about the same as the diameter of the woofer.
Is it true then that a passive radiator with Sd = 50 sq.cm. and Xmax = 8 mm would be sufficient for a woofer with the same Sd and Xmax = 4 mm?
Essentially, it means that the diameter of the passive radiator can be about the same as the diameter of the woofer.
Good question. I just assume that it's at CD sound quality or better. So passive radiators would help keep lower frequencies, provided they are selected and installed properly.
Yep!
You could get away with low xmax woofers by taking passive radiators with more than 2x the displacement of the woofers and use an equalizer to boost around the tuning frequency. At those frequencies the PR is doing most of the displacement. I believe this is what JBL is doing, judging from the large peak at 75 Hz on some of their models. This would require a DSP.
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I use a Playstore app called Bass Eq which works with everything including YouTube on my phone with my portable speaker. It has a pair of ND91's, AMT tweeters and a 6.5 "Dayton PR to make the most of their big X max/ mech.
I made a small boombox using a pair of 3.5" car coax speakers, so there was no crossover needed. The amplifier board that I chose doesn't have Bluetooth, but I could buy a separate Bluetooth receiver. It runs on a 12V power supply that plugs into the wall, or 8 AA batteries. The sound quality is quite good.
There are a lot of amp boards with or without Bluetooth, different power ratings, etc. And you can find other speakers. If you want to build your own enclosure, you can customize it the way you want it.
There are a lot of amp boards with or without Bluetooth, different power ratings, etc. And you can find other speakers. If you want to build your own enclosure, you can customize it the way you want it.
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Best I have heard is SONY SRS-XB31 the XB stands for Xtra Bass. The only problem is that it requires iPhone app to change settings. Unfortunately it is hopeless for audiobook playback as extra bass must be synthesised as voices sound too boomy. Another Ali Express one model S200C has less bass and is great for normal speech and most music. SONY one is 4X the price of AliExpress one. Both easy to pair with iPad or iPhone and battery life is very good withSONY.
I wouldn't call either hifi, but ok for casual orbackground music. I also have an old Logitec unit that plugsinto USB port of any computer and receiver has RCA sockets that can connect with any integrated amplifier and speakers. Quality this way is excellent although I think that bluetooth compresses the dynamic range, but that is not too important for background or outside listening. Your choice, but audition any shop bought unit with your phone or tablet and check if unit requires app for full functionality.
Oh yeah, SONY comes with colour lght show which can (thankfully) be turned off by a button on the back panel as this novelty soon wears off. Goodfor party time though.
Ozzi
I wouldn't call either hifi, but ok for casual orbackground music. I also have an old Logitec unit that plugsinto USB port of any computer and receiver has RCA sockets that can connect with any integrated amplifier and speakers. Quality this way is excellent although I think that bluetooth compresses the dynamic range, but that is not too important for background or outside listening. Your choice, but audition any shop bought unit with your phone or tablet and check if unit requires app for full functionality.
Oh yeah, SONY comes with colour lght show which can (thankfully) be turned off by a button on the back panel as this novelty soon wears off. Goodfor party time though.
Ozzi
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Thanks Marty! How does stereo sound when drivers are close to each other, like in photos 3 and 4?
Dave, nice build! Thank you for sharing! Yours have two drivers. Would rechargeable batteries inside be also practical to power up a small enclosure speaker with two tweeters and two woofers all with crossovers? Would a speaker with 8 Ohm drivers play longer on batteries than with 4 Ohm drivers, or the difference is not that important compared to the other components' share?
Hiya, its better to have separate enclosures for the mid bass but there's no stereo effect in my 12" wide box so I don't think I'm missing much. When I came up with my design, there weren't any suitable smaller PR"s for separate chambers. The drivers are good quality with low distortion and it goes plenty loud with bass strong to 55hz with a little help from the eq app. I used the crossover design from Tom Zarbo's 'Bantam' speakers ( check out Parts Express Tech Talk forum for loads of DIY goodness!). The Bluetooth 4 sounds great on the eBay TPA 3116 stereo amp. I've got all the parts for a 2.1 big brother with a Tang Band W5 sub as my next bass heavy project.
Thanks.
The amp board that I used has input locations for adding 12Vdc worth of batteries. (the leads need to be soldered to the board) However that particular board doesn't have recharging capability by itself. At moderate levels, the (8) AA batteries will run the 3.5" coax speakers for a couple days or more, before having to replace them. If the 12Vdc power supply is plugged in to the wall, the batteries are not used. The amp module that I chose was rated at 4 ohms, so I chose 4-ohm speakers.
There are add-on boards that will hold rechargeable batteries -- and recharge them. There is a wide variety of different amp module boards available to choose from, with lots of different features and wattage output to suit what you want. I don't have any affiliation with them, but Parts Express has quite a few to look through. The possibilities seem limited to one's imagination -- and budget of course
. I chose to keep the design as simple and compact as possible. It's just a little bigger than a box of kleenix. I figured it would be used mostly where it could be plugged in, and only occasionally where it needed to run on the batteries. Making the back panel removeable -- and still keep it sealed -- added complications, but everything inside including the batteries is accessible.
I am planning on making a more deluxe model later this year. My plan is to incorporate Bluetooth and rechargeable batteries, along with a few other features that I've been thinking about. Haven't got that far with that one yet.
Actually was referring to audio amp modules/boards and accessories.
Audio Amplifier Boards & Modules in the Electronic Parts Department at Parts Express | 3464
This is the amp board w/volume control that I used.
Dayton Audio DTA-2 Class D Digital Audio Amplifier Module
And these are the 3.5" car coax speakers.
Kicker DSC350 DS Series 3-1/2" 2-Way Coaxial Speaker Pair
Yes, got it! I meant numerous combinations of components for what I want to build. Thanks for the links!
Hiya Harum, my design uses (almost) the same drivers as Tom's Bantam so I borrowed his xover design and it seems to do a good job. It wouldn't work with different speakers. I use a 24v Lipo rechargeable battery I got from Aliexpress. Lasts well (at least 10-12 hours loud!)
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