WinXP directly driving two 4-way active speakers
Posted: Wed Apr 23, 2014 12:43 am
Since a few years I'm using an old WinXP SP3 computer dating back from 2007 as infotainment center in my living room, HDMI connected to a big TV screen, and DVI-connected to a desktop-sized screen. I'm using it everyday for surfing on internet, read and write emails, watch videos on YouTube, listen to music using Winamp and watch movie (in stereo, not in 5.1) using MPC-HC, which is a decent movie player bundled with the K-Lite Codec Pack bundle.
What makes this setup so special, is that it always runs an .exe compiled by Flowstone, what's regarding the sound. This way, my old WinXP computer embeds a stereo 4-way crossover. Each speaker driver gets individually filtered by a combination of IIR Biquad filters, FIR filter, and delay. For each speaker driver, the FIR filter gets automatically setup using a realtime dual-channel FFT analyzer, realtime gain/phase comparator (comparison with the target gain/phase), realtime inverse FFT computation delivering the required filter impulse response, which indeed describes the required FIR coefficients. This way one single FIR filter inherently combines the speaker linearization function, and the speaker filtering function defined by the crossover goals.
This is done by Speaker Lab, another Flowstone application I completed a few months ago.
You can see it here : viewtopic.php?f=3&t=1607
The 7.1 audio system outputs eight audio channels. Four channels go to the left speaker. Four channels go to the right speaker. You thus need four stereo power amplifiers. For a medium-sized living room I would recommend four BTL Class AB TA8254-based stereo power amplifiers designed for car audio and motorcycle audio (Lepy LP-V3s). They need a 12 Volt DC power supply. There are 12 Volt 60 Watt switching power supplies available nowadays. One 12 Volt 60 Watt power supply can power two stereo amps. You thus need two 12 Volt 60 Watt switching power supplies. Regarding the Lepy LP-V3s, in case you have electronics skills, you can bypass the JRC4558 Opamp, tone controls, and volume control. The TA8254 maximum tolerable supply voltage is 18 Volt when not hot. Knowing the reservoir cap is a 2,200µF/16V, the power supply should never exceed 15 Volt. You may double or triple the capacitance, soldering more 2,200µF/16V capacitors in parallel. Make sure they exhibit a low ESR (equivalent series resistance), and can withstand a 105°C temperature. In case you want to extract the maximum power from the TA8254, you may go for a 15 Volt 70 Watt power supply. Possibly the Lepy LP-V3s are cheap alternatives of the LePai LP-V3, presented as audiophile-grade BTL Class AB TDA8566-based stereo power amplifiers (I have not these). Finally, remember to put back enough silicon grease on the power amplifier IC when re-assembling those little amplifiers. As soon as they overheat, they shut down as a matter of protection.
Be very careful, when dealing with multiway active speakers.
Never connect or disconnect a jack or a cinch while a power amplifier is still on.
Always remove the power supply from the amplifiers, before connecting or disconnecting any jack or cinch.
If you fail to observing the rule, you run the risk of damaging the speaker driver that's connected on the power amplifier, the one you moved the jack or the cinch.
When dealing with multiway active speakers, the power amplifier volume pots need to stay fully open. Any glitch coming into the power amplifier can thus be fatal for the speaker driver.
Here are the steps required for setting up the system, what's regarding software.
Actually this is a memo for myself.
Without it, each time I try installing the whole thing, I miss something.
- install the SWEEX SC016 8-channel USB-audio attachment using the Windows XP driver that's supplied by SWEEX
- such install adds an icon at the right bottom side of the screen - it's labelled "USB Multi-Channel Audio Device"
- click the "USB Multi-Channel Audio Device" icon for configuring the SWEEX SC016 in 8 channels (by default it comes configured in 2 channels only)
- install VAC and make sure it is licenced (otherwise it periodically generates a noise)
- install ASIO4ALL, remembering to configure it later on, in "advanced mode"
- open the Windows Sound Control Panel
- go in the "Audio" tab and select "Virtual Cable 1" for the Default Audio Play and "Virtual Cable 1" for the Default Audio Record
- go in the "Sounds" tab and select "no sounds" - this will ease Windows job (no more beeps to process and mix)
- launch Flowstone and add the ASIO-in component and the ASIO-out component on a new, blank schematic
- ASIO4ALL should wake up, the ASIO4ALL icon should appear at the right bottom side of the screen - it's labelled "ASIO4ALL v2 - Flowstone"
- for configuring ASIO4ALL in advanced mode, click the ASIO4ALL icon in the tray, the ASIO4ALL configuration windows pops up, and for accessing the advanced settings you need to click the "tool" icon on the bottom right corner
- look the "+" symbol preceding each device in the WDM Device List : AMD High Definition Audio Device (that's the HDMI on the motherboard), Realtek High Definition Audio (those are the audio jacks on the motherboard), Virtual Audio Cable, and USB Multi-Channel Audio Device (this is the SWEEX SC016).
- only "Virtual Audio Cable" and "USB Multi-Channel Audio Device" must be active
- click the "+" in front of "Virtual Audio Cable" - over there, only the "In" should be active
- click the "+" in front of "USB Multi-Channel Audio Device" - over there, only the "Out" should be active
- go back to Flowstone, and make sure that the ASIO-in and the ASIO-out modules are activated - in the schematic, you may need to click on the "ASIO4ALL v2" labels for getting them blue instead of grey
- blue labels over there mean that Flowstone has properly detected the installation and the configuration parameters of the SWEEX SC016, VAC and ASIO4ALL
- regarding ASIO-in, make sure the ports are labelled "Virtual Cable 1.1" to "Virtual Cable 1.8" - actually we will only use Virtual Cable 1.1 port and Virtual Cable 1.2 port
- regarding ASIO-out, make sure the ports are labelled "Audio Device 1" to "Audio Device 8" - we will use them all for a stereo 4-channel crossover
- of course, the crossover should sit between ASIO-in and ASIO-out
- any kind of crossover can now be designed : IIR Biquad filters based, FIR filters based, adding delays, subtractive schemes also, etc.
- thanks to Flowstone graphical programming, this is a matter of minutes instead of weeks or months
I won't go in the details regarding the crossover, as this is living matter, depending on personal skills and preferences.
- Some want a digital crossover imitating the analog Linkwitz-Riley.
- Some want the gain curves of the analog Linkwitz-Riley, without the phase distortion.
- Some want sharper curves than the Linkwitz-Riley, and symmetric, and no phase distortion.
- Some want delay-compensated Bessel-lowpass-based subtractive schemes.
- Some want the Baekgaard crossover basing on the 2nd-order state-variable-filter . Actually, this is a 3-way crossover, the simplest crossover, however exhibiting a 180 phase shift between the woofer and the tweeter.
- Some want to hook a subwoofer, adding the subwoofer phase shift to the midbass-high medium satellite for avoiding relative phase shifts.
- Some want to try bidirectional (inherently phase linear) IIR filters
- Some want to try Almost Linear-Phase Polyphase IIR filters
- Some want to try Berchin's FDLS method for designing arbitrary magnitude and phase filters using IIR filters
- Some want to try "frequency warped" filters, using a relatively short convolver having its delay cells replaced by allpass (phase shifter) cells
All what's above, Flowstone can do it, the way you want it.
Just ask Flowstone to generate the .exe, when you are happy about your schematic.
Put such .exe in the "Start" list in Windows, so it automatically executes after each boot.
Flowstone is also able to export using the VST modality.
You may thus distribute your preferred crossover as a VST.
This way you enter the PRO-AUDIO market.
What makes this setup so special, is that it always runs an .exe compiled by Flowstone, what's regarding the sound. This way, my old WinXP computer embeds a stereo 4-way crossover. Each speaker driver gets individually filtered by a combination of IIR Biquad filters, FIR filter, and delay. For each speaker driver, the FIR filter gets automatically setup using a realtime dual-channel FFT analyzer, realtime gain/phase comparator (comparison with the target gain/phase), realtime inverse FFT computation delivering the required filter impulse response, which indeed describes the required FIR coefficients. This way one single FIR filter inherently combines the speaker linearization function, and the speaker filtering function defined by the crossover goals.
This is done by Speaker Lab, another Flowstone application I completed a few months ago.
You can see it here : viewtopic.php?f=3&t=1607
The 7.1 audio system outputs eight audio channels. Four channels go to the left speaker. Four channels go to the right speaker. You thus need four stereo power amplifiers. For a medium-sized living room I would recommend four BTL Class AB TA8254-based stereo power amplifiers designed for car audio and motorcycle audio (Lepy LP-V3s). They need a 12 Volt DC power supply. There are 12 Volt 60 Watt switching power supplies available nowadays. One 12 Volt 60 Watt power supply can power two stereo amps. You thus need two 12 Volt 60 Watt switching power supplies. Regarding the Lepy LP-V3s, in case you have electronics skills, you can bypass the JRC4558 Opamp, tone controls, and volume control. The TA8254 maximum tolerable supply voltage is 18 Volt when not hot. Knowing the reservoir cap is a 2,200µF/16V, the power supply should never exceed 15 Volt. You may double or triple the capacitance, soldering more 2,200µF/16V capacitors in parallel. Make sure they exhibit a low ESR (equivalent series resistance), and can withstand a 105°C temperature. In case you want to extract the maximum power from the TA8254, you may go for a 15 Volt 70 Watt power supply. Possibly the Lepy LP-V3s are cheap alternatives of the LePai LP-V3, presented as audiophile-grade BTL Class AB TDA8566-based stereo power amplifiers (I have not these). Finally, remember to put back enough silicon grease on the power amplifier IC when re-assembling those little amplifiers. As soon as they overheat, they shut down as a matter of protection.
Be very careful, when dealing with multiway active speakers.
Never connect or disconnect a jack or a cinch while a power amplifier is still on.
Always remove the power supply from the amplifiers, before connecting or disconnecting any jack or cinch.
If you fail to observing the rule, you run the risk of damaging the speaker driver that's connected on the power amplifier, the one you moved the jack or the cinch.
When dealing with multiway active speakers, the power amplifier volume pots need to stay fully open. Any glitch coming into the power amplifier can thus be fatal for the speaker driver.
Here are the steps required for setting up the system, what's regarding software.
Actually this is a memo for myself.
Without it, each time I try installing the whole thing, I miss something.
- install the SWEEX SC016 8-channel USB-audio attachment using the Windows XP driver that's supplied by SWEEX
- such install adds an icon at the right bottom side of the screen - it's labelled "USB Multi-Channel Audio Device"
- click the "USB Multi-Channel Audio Device" icon for configuring the SWEEX SC016 in 8 channels (by default it comes configured in 2 channels only)
- install VAC and make sure it is licenced (otherwise it periodically generates a noise)
- install ASIO4ALL, remembering to configure it later on, in "advanced mode"
- open the Windows Sound Control Panel
- go in the "Audio" tab and select "Virtual Cable 1" for the Default Audio Play and "Virtual Cable 1" for the Default Audio Record
- go in the "Sounds" tab and select "no sounds" - this will ease Windows job (no more beeps to process and mix)
- launch Flowstone and add the ASIO-in component and the ASIO-out component on a new, blank schematic
- ASIO4ALL should wake up, the ASIO4ALL icon should appear at the right bottom side of the screen - it's labelled "ASIO4ALL v2 - Flowstone"
- for configuring ASIO4ALL in advanced mode, click the ASIO4ALL icon in the tray, the ASIO4ALL configuration windows pops up, and for accessing the advanced settings you need to click the "tool" icon on the bottom right corner
- look the "+" symbol preceding each device in the WDM Device List : AMD High Definition Audio Device (that's the HDMI on the motherboard), Realtek High Definition Audio (those are the audio jacks on the motherboard), Virtual Audio Cable, and USB Multi-Channel Audio Device (this is the SWEEX SC016).
- only "Virtual Audio Cable" and "USB Multi-Channel Audio Device" must be active
- click the "+" in front of "Virtual Audio Cable" - over there, only the "In" should be active
- click the "+" in front of "USB Multi-Channel Audio Device" - over there, only the "Out" should be active
- go back to Flowstone, and make sure that the ASIO-in and the ASIO-out modules are activated - in the schematic, you may need to click on the "ASIO4ALL v2" labels for getting them blue instead of grey
- blue labels over there mean that Flowstone has properly detected the installation and the configuration parameters of the SWEEX SC016, VAC and ASIO4ALL
- regarding ASIO-in, make sure the ports are labelled "Virtual Cable 1.1" to "Virtual Cable 1.8" - actually we will only use Virtual Cable 1.1 port and Virtual Cable 1.2 port
- regarding ASIO-out, make sure the ports are labelled "Audio Device 1" to "Audio Device 8" - we will use them all for a stereo 4-channel crossover
- of course, the crossover should sit between ASIO-in and ASIO-out
- any kind of crossover can now be designed : IIR Biquad filters based, FIR filters based, adding delays, subtractive schemes also, etc.
- thanks to Flowstone graphical programming, this is a matter of minutes instead of weeks or months
I won't go in the details regarding the crossover, as this is living matter, depending on personal skills and preferences.
- Some want a digital crossover imitating the analog Linkwitz-Riley.
- Some want the gain curves of the analog Linkwitz-Riley, without the phase distortion.
- Some want sharper curves than the Linkwitz-Riley, and symmetric, and no phase distortion.
- Some want delay-compensated Bessel-lowpass-based subtractive schemes.
- Some want the Baekgaard crossover basing on the 2nd-order state-variable-filter . Actually, this is a 3-way crossover, the simplest crossover, however exhibiting a 180 phase shift between the woofer and the tweeter.
- Some want to hook a subwoofer, adding the subwoofer phase shift to the midbass-high medium satellite for avoiding relative phase shifts.
- Some want to try bidirectional (inherently phase linear) IIR filters
- Some want to try Almost Linear-Phase Polyphase IIR filters
- Some want to try Berchin's FDLS method for designing arbitrary magnitude and phase filters using IIR filters
- Some want to try "frequency warped" filters, using a relatively short convolver having its delay cells replaced by allpass (phase shifter) cells
All what's above, Flowstone can do it, the way you want it.
Just ask Flowstone to generate the .exe, when you are happy about your schematic.
Put such .exe in the "Start" list in Windows, so it automatically executes after each boot.
Flowstone is also able to export using the VST modality.
You may thus distribute your preferred crossover as a VST.
This way you enter the PRO-AUDIO market.