Single Speaker Stereo or SSS

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Pic.1 Connection method used

     The way connection is done in Baffless SSS is in  Pic.1. This is kind of delta connection instead of star. This is because amplifiers used are floating load amplifiers and star connection will not work.  This connection is more complicated than it looks. It's because the amplifiers used are with varying output impedance vs frequency. Resistor in series with the front driver is used to make about equal output from all drivers for center panned signal. So the speakers acts as monopole source with equal output front/left/right. The sound is spread more evenly across the room. Power response is a little better, because highs and lows  are more correct at extreme left and right. Center panned signal is chosen to be a reference point for equalising the speaker, because vocals usually are center channel located and are most important part of the music.

    

   

    Amplifiers used in this speaker are Baffless amplifiers. They are separate topic as they are very unique. DAC and amplifier integrated into one board guaranties the end performance to be perfect. If in example the user uses very good DAC with 120dB performance and an Amp with the same performance it is not guarantied that the end performance will be 120dB. There are many things that can go wrong. Ground loops, EMI noise, interconnections an so. Noise floor of Baffless amplifier is below 120dB, THD in 0,000x range.(measurement equipment is a limiting factor for now to measure exactly). Amplifier is universal. It has integrated Sabre DAC and is fully galvanically isolated from digital source and standby power source.  Has protections, auto power on/off. Click free on/off. Output transistors are 900W rated for short term power, no electrical isolation pads required. Easy reliable mounting. Amp designed to be reliable as reliable can be.  Can be configured as voltage amp, current amp or mixed mode amp. In this speaker they are configured as mixed mode amps. So voltage for low frequencies and current for high frequencies. This is done to get lower distortions from dynamic loudspeakers. This gives more open sound, true-life like sound.  Distortions in loudspeaker drivers are vastly greater than in amplifiers so it is wise to take them down.  

THD current drive vs voltage drive
THD current drive vs voltage drive

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current(black) overlayed over voltage imd
current(black) overlayed over voltage imd

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current 5khz
current 5khz

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THD current drive vs voltage drive
THD current drive vs voltage drive

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Pic.2 Current drive vs voltage drive

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Pic.3 Baffless amplifier

     Speaker has three streaming options. It is DLNA, Airplay and Roon. The Airplay streaming was the first in development process because it is just works from apple devices. It is simple to use, reliable and no setup needed. In other words user friendly. And there is no easy way to manipulate the stream with equaliser or so without third party apps. I think it is not good if the user use EQ. There are several reasons for that, but in one sentence:  average user probably more likely will ruin and not fix the sound with equaliser.

     The second streaming option is Roon app. This is because it is of higher quality than Airplay. Roon uses it's own developed RAAT protocol for streaming. It supports higher sample rate and bit depth compared to Airplay's CD quality 44,1kHz 16Bit quality. It works with audio backend clock source. Sends data when needed. So can work without any resampling or one resampling less compared to Airplay. Roon app is popular among audiophile community. The hardware capabilities of Baffless Single Stereo Speaker are way better than standard  CD quality 44,1kHz 16Bit quality so Roon has to be used to get best possible. 

     The third option for streaming was chosen DLNA. Because Roon is very good, but expensive App. And android users are left without Airplay. So DLNA is for android users mainly.  

     Digital part is developed with care. Every chain of digital signal transmission is checked to make sure everything is correct. Many people think that digital part is always correct. You stream 96kHz and 24bit and you get exactly that into DAC. No it's not the case very often. There are many processes involved in between and many things can go wrong. Settings can be not optimal. The code can have bugs. I test digital signal by looking at the spectrum and making long term peak hold metering. Pic. 4, Pic.5. 

Also i have done audio file that outputs samples with the same bit pattern. Every sample is the same. So it is easy to see the correctness of the  bits with the scope on I2S line at DAC side. With the scope i can see actual word length. Is it 16/24/or 32 bits. See most and least significant bits and how they behave. And see if there are any problems. If someone needs a file with all the same samples just contact me as the file is too big to upload here. Just be careful as this file outputs DC. So if you gear is DC coupled, keep in mind and don't damage something. Baffless amplifier is fully DC coupled and can be used as adjustable DC voltage or current source.

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    Pic.4 Airplay digital stream 1khz noise floor peak hold mode

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    Pic.5 Roon digital stream 1khz noise floor peak hold mode

      Will be more info..