Topic: Ghetto Wireless Speaker Build (Read 9688 times)

jmone · « **on:** February 26, 2015, 10:21:05 pm »

Here is my Ghetto Airplay/DLNA/Wifi/BT/Local Player Active Speaker (V1) made from bit I had around (except the amp):
- Axiom Audio On Wall Speaker
- 2 x 50w amp
- FiiO E10 DAC
- Nexus 7 (2013) Running Android 5.0.2 with a EOS/Gizmo and an Airplay Receiver
- Bunch of cables, Velcro Dots etc

It all works (but looks ugly).... Matt would be proud!

Some Notes:
- There is a definite improvement in sound quality and SPL using a signal path of OTG USB Cable --> E10 DAC --> Amp rather than Headphone out --> Amp
- As this is only one speaker I'm only use one channel on the Amp. From a quick google I don't think you can just bridge the L & R output of the amp to feed the speaker
- These little digital amps are fine at low vol but you start to hear distortion on Max Vol (even though the speaker is rated at 200w).
- I should get a short "OTG Male Mini USB <--> Mail Micro USB" to connect the tablet to the DAC and I think you can also get one that allows for the tablet to also be charged. That said the Tablet had no issues powering the E10 DAC.
- I should also get a short "3.5mm Stereo <--> Mono RCA or Mono 3.5mm" to connect the DAC to the Amp.

A bit of (useless) fun!
Thanks
Nathan

jmone · « **Reply #1 on:** February 27, 2015, 11:33:43 pm »

I was having issue with Stereo Sources --> Stereo Amp --> One Speaker and how to bridge the output without causing a bunch of distortion or blowing something up ... or be stuck with just one Channel. I also tried a bunch of stuff with Y cables etc that did not work (mostly produced a distorted output or had lots of pops/click/static etc).

Mr Google had heaps of posts on how to "Sum stereo to mono line level inputs" but in this case I wanted to accept stereo and output it to a songle speaker. Turns out what I wanted to do was "Passive stereo to mono speaker level summing" and to do that I needed to add a 6+ohm 10watt resistor on each positive line and use only one of the negative lines from the amp to the speaker (common ground) from per this post. See Pics

I now have clear audio with content from both channels producing 100db/1m (peak C Weighted) from this setup.

Warning: I don't know squat about electronics so this is a post on what worked for me and is not a recommendation! YMMV with potential results ranging from a similar setup to blowing your amp, speakers, or causing a singularity and the end of mankind.

Hilton · « **Reply #2 on:** February 28, 2015, 12:00:21 am »

Nice one. I'm sure my ghetto prototype will be even more ghetto!

I'm cleaning the house with 5 zones of AirPlay sync. Definitely more motivating to get work done when you can belt out some tunes around the house while the missus is shopping. Having a BBQ tonight so it will be getting a good workout.

jmone · « **Reply #3 on:** February 28, 2015, 12:11:07 am »

Now to get either:
- OTG Adapter with Power (charge tablet/phone while connected to the DAC)
- Qi (Wireless) Charging Dock so I can use a std OTG adapter to the DAC

I have to say the DAC is the way to go. It is much louder and far better quality than the Headphone Socket.

Other option is to get another Airport Express, but I have heaps of Android Tablets (and old phones) I'd rather re-purpose, if could find a Good Airplay app for Android however

The interesting thing about this speaker "in wall" format is I can end up boxing it all and hide all the bits.... if I don't grow bored with the whole project that is.

Have a good BBQ!

6233638 · « **Reply #4 on:** February 28, 2015, 02:20:25 am »

That's looking pretty good now. Probably sounds a lot better than most AirPlay speakers too.

jmone · « **Reply #5 on:** February 28, 2015, 04:18:48 am »

Yup - sounds much better than the Pio esp on the Bass extension and SPL. It also weighs 3 times as much! I should have spent more time finding a quality value for money amp instead of grabbing what was off the shelf at the local tech store but it works ok now I've got the bridging sorted. I was thinking of you and considered bolting a battery / charger underneath but then got a grip on myself!

mwillems · « **Reply #6 on:** February 28, 2015, 05:56:20 am »

Quote from: jmone on February 27, 2015, 11:33:43 pm

I was having issue with Stereo Sources --> Stereo Amp --> One Speaker and how to bridge the output without causing a bunch of distortion or blowing something up ... or be stuck with just one Channel. I also tried a bunch of stuff with Y cables etc that did not work (mostly produced a distorted output or had lots of pops/click/static etc).

For future reference, the place to put the Y cable is between the DAC and the amp. It's not perfect, but that's the "right" way to do it if you have to work with an analog signal and can't downmix.

Most little class D amps cannot be bridged, often because they're really effectively "pre-bridged" 4-channel chips from the factory being used as two channel chips (which is why their power output is almost always rated against 4 Ohms instead of 8 )

jmone · « **Reply #7 on:** February 28, 2015, 03:27:14 pm »

As per my post, that's exactly what I started with, but turns out the Y cable is not a good idea to combine (rather than split) signals...I was even warned by the electronics shop before hand this was a bad idea. So after ignoring the advice and learning first hand that it indeed sounded bad I did some searching and this article kept being referenced on "Why not to use Y cables". I could have done a Line Level Summing circuit as shown in the article but I'd need two (one between the DAC and the AMP + the AMP also has a 3.5mm input on the front so I'd need one for this as well). My solution does it out the output and did not require any soldering.

Hilton · « **Reply #8 on:** March 01, 2015, 06:54:21 am »

I think I'll design something similar to the Audioengine B2. It's a nice looking speaker but it could do with some more guts and better input options.

http://turntablelab.com/collections/speakers-alpha/products/audioengine-b2-bluetooth-desktop-speaker-zebrawood

jmone · « **Reply #9 on:** March 02, 2015, 02:58:11 am »

Looking forward to what you come up with. I was looking at adding the guts of the little Amp, DAC to a project box with USB power and connectors but in the process busted some vital bit off the DAC.... which is now in the bin. Now thinking about if I replace the DAC, or get another Airport Express instead as the source, or even strip the bits out of a Pio A1 (DLNA, Airplay, Wireless, Wired etc).....

Hilton · « **Reply #10 on:** March 02, 2015, 08:26:11 pm »

Pi 2 arrived. Time to play.

I'll start my own thread when I get underway.
I think I'll be building a kit amp 40-60W and adding a simple USB DAC to the Pi. Just looking through a few options.

jmone · « **Reply #11 on:** March 02, 2015, 08:29:56 pm »

Sounds like a plan. The other option I have is to use the Compute Stick I have as while underpowered for Video would be fine as a Audio Renderer but need a way to get the audio off it (DAC or Audio Extractor I guess).

horse · « **Reply #12 on:** March 03, 2015, 10:34:11 pm »

On Amazon in the US there is this. Not load enough for Nathan but might be a useful starting point to hack from

http://www.amazon.com/Dreamsound-Speaker-Wireless-Audiophiles-Supports/dp/B00OLIFQ92/ref=cm_cd_ql_qh_dp_t

No idea of quality, but thought I'd throw it out there.

Use RPi for AirPlay but without the add on DAC the analogue sound is so so. HDMI of course is more useful but now life gets complicated. Today it gets plugged into an AVR and it's cheaper to go buy a new low end AVR with AirPlay for US$200.

I'm looking for an all in one wireless speaker with remote including power and sleep timer. Or auto standby when no activity for a period of time.

Hilton · « **Reply #13 on:** March 03, 2015, 11:05:05 pm »

Quote from: horse on March 03, 2015, 10:34:11 pm

On Amazon in the US there is this. Not load enough for Nathan but might be a useful starting point to hack from

http://www.amazon.com/Dreamsound-Speaker-Wireless-Audiophiles-Supports/dp/B00OLIFQ92/ref=cm_cd_ql_qh_dp_t

No idea of quality, but thought I'd throw it out there.

Use RPi for AirPlay but without the add on DAC the analogue sound is so so. HDMI of course is more useful but now life gets complicated. Today it gets plugged into an AVR and it's cheaper to go buy a new low end AVR with AirPlay for US$200.

I'm looking for an all in one wireless speaker with remote including power and sleep timer. Or auto standby when no activity for a period of time.

Weird design having the tweeters in the centre. Bad for stereo imaging. Nice concept and finish though.

Hilton · « **Reply #14 on:** March 04, 2015, 06:30:35 am »

Here's my semi-ghetto speaker mod with Pi2 running MC20 powered off the Sony SRS-X7 Speaker.
http://yabb.jriver.com/interact/index.php?topic=96006.0

jmone · « **Reply #15 on:** March 06, 2015, 03:32:54 am »

Attempt 2 : Use a PCB from a Wireless Speaker.

I got a cheap Pio A1 (sans adapter) and have pulled the circuit board out. It supports Airplay, DLNA, has wireless & wired connections and is perfectly in sync with my other setups. I can tap the High Level outputs just fine and feed it to the amp setup above via a Hi-Lo adapter to convert speaker level to line level, and while it "works" the sound quality is not that good with some buzz and harshness + this tap is post a cross over separating a tweaker from the mix. What I need to find on this board is where I can tap the Line Level ... but I've no idea on where to start. $:-\$

jmone · « **Reply #16 on:** March 06, 2015, 03:44:03 am »

Attempt 3 : Use the (clone) Intel Stick

This should be easy as the Android Tablet setup, but using the (clone) Intel Stick + Airfoil Speak / MC + DAC (I've replaced the one I broke with the later FIIO E10K). I'm starting to hate that little finicky stick. I've kind of got it close to working so that:
- It will boot headless into Win 10 (auto logon) from connection to power
- The DAC will power up from the USB slot just fine
- I can even RDP into it (without a password)

Thing is when headless I'm not getting any audio output when headless. It is kind of hard to work out as:
- While headless, if I RDP into it I can not see any Audio Devices as you only see the Remote Audio Adapter for the session so I have no idea what audio devices is selection but;
- If I add a hub (so I have mouse/kb to config the thing) then it is fine even when headless.... so I'm guessing the Audio deivce "looks different" when it is on the Hub.....

..... I'm going to have to get a BT keyboard to find out what this thing is up to....

Edit - Got it sorted! The stick as a second USB Port (Micro) and I had a Female - Female USB adapter I could plug two Micro to USB cables into. The issue was the DAC was being enumerated differently between being plugged in directly VS via the Hub.

Now all working! I need to get a small Micro <--> Micro USB cable and I'm all set. I may still use a better WiFi adapter as the one in the Stick is serious poor!

Edit 2 - Added a little WiFi Adapter to the Stick and it is now much much better. Not dropping packets at all and staying in sync perfectly

jmone · « **Reply #17 on:** March 07, 2015, 08:47:05 pm »

Here is the "finished" product all mounted in a project box that has:
- Stereo output (with a stereo to mono summing cable when driving on speaker)
- Heaphone output
- USB DAC & Analogue input (auto switch)
- USB Power (to power Tables, Stick etc)

The result is I can run a
- Tablet using EOS/Gizmo etc from an OTG cable
- Headless Windows Box (Stick) running Airfoil Speakers and/or MC as a Zone

Well it was a "fun" project, but better of to just buy something off the shelf!

jmone · « **Reply #18 on:** March 08, 2015, 01:17:05 am »

Ahhhh still more to do. Seems sharing the PS with the AMP & Player (and hence DAC) is creating a ground loop with pops, hiss, warble etc. Only impacts the Stick as the Tablet using wireless charging (so I guess it is on a separate "circuit").

Hilton · « **Reply #19 on:** March 08, 2015, 01:40:44 am »

Quote from: jmone on March 08, 2015, 01:17:05 am

Ahhhh still more to do. Seems sharing the PS with the AMP & Player (and hence DAC) is creating a ground loop with pops, hiss, warble etc. Only impacts the Stick as the Tablet using wireless charging (so I guess it is on a separate "circuit").

Not quite so ghetto now! Nice work.

You should check out my ghetto wireless 1TB Pi running MC20 Arm. I need to do something similar with a project box and miniaturise the bits and tidy it up.

http://yabb.jriver.com/interact/index.php?topic=96006.msg662455#msg662455

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Author Topic: Ghetto Wireless Speaker Build (Read 9688 times)