2.1-channel amplifiers are convenient, but there are many more options
available if you look at single-channel, 2-channel, or 4-channel
amplifiers, without the integrated crossover.
In car audio, the most common setup is to use a 2-channel amplifier
for the main stereo speakers and a separate "monoblock"
(single-channel) amplifier for the subwoofer. As a result, if you
shop for car amplifiers, you'll find tons of 2-channel and monoblock
options, and very few 2.1-channel options.
This type of setup is actually easy to implement on Windows, as long
as your motherboard or sound card supports 5.1 or 7.1 channel output.
The secret is to let Windows handle the crossover, so that you
don't need a separate crossover circuit in the amplifier, which a
2.1-channel amp would normally provide. Your PC audio outputs should
include a jack with "Center/Subwoofer" output, usually color-coded
Why would you want to do this? Because it gives you more options
when shopping for amplifiers. You don't have to limit yourself
to the small number of 2.1 amplifiers available; you can use just
about any car amp.
Note: some amplifiers use 1/8" stereo jacks for their inputs instead
of RCA connectors. Substitute a cable with 1/8" stereo plugs at both
ends in that case.
Be sure to read the section below on configuring Windows for separate
subwoofer output. You have to make some settings changes in Windows
before it'll send any sound output to the subwoofer jack.
Follow the instructions below to configure Windows for this setup.
If you're using the subwoofer output from your PC audio output, you
have to go through some extra steps to make Windows handle the
crossover, so that Windows distributes the sound properly between the
main speaker and the subwoofers.
Audio amplifiers for cars run on 12VDC (like almost everything else in
a car), which makes them easy to adapt to a pin cab, where we already
tend to have a 12V power supply handy. And there's a huge selection
of car amps available.
The biggest reason to consider car amps is that they tend to have
reliably good audio quality, especially compared to the other options
we'll see below. I ended up using a 4-channel car amplifier for my
main speakers (the backbox and subwoofer channels) after trying the
Lepai and DIY amplifier types and deciding that their sound quality
There are lots of inexpensive amplifier boards available these days
designed for hobbyists building Arduino projects or DIY audio systems.
I call these DIY amplifiers, but they're not DIY in the sense that you
have to build them, just in the sense that they're for DIYers.
The ones I'm talking about are actually fully assembled circuit
boards. What makes them DIY is that they don't come with enclosures;
they're just bare circuit boards. Which works fine in a pin cab,
where the cabinet can serve as the enclosure, just like for the PC
You can find many options from Chinese sellers on eBay, and several
are available on Amazon.
I've had poor results with these so far, unfortunately, so I don't
have any first-hand recommendations to offer. The ones I've tried had
unacceptable background noise levels (that is, noise playing through
the speakers when no audio was playing on the PC). This problem
actually afflicts a lot of amplifiers in a pin cab environment,
because we power them with switching power supplies. An amplifier
needs quite good power line filtering to sound good with a noisy power
source, and most of these hobbyist boards have little or no power
conditioning, to keep the cost down.
All of the DIY amplifier boards are based on specific integrated
circuit chips that do most of the amplifier work, so when you go
shopping for these, you'll find them identified primarily by the type
of IC chip they use. These are all no-brand products, though, so one
board based on a particular chip might be great, and another board
based on the same chip might be terrible. It's a crap shoot if you
buy these on eBay. I think your best bet might be to buy these on
Amazon, where you can at least compare user reviews, even if those
aren't perfectly reliable.
Be sure to look for a board that works on an ordinary DC power supply.
Some of the older amplifier IC chips needed AC power supplies (using
transformers) or require unusual DC voltage levels. The newer chips
are mostly designed for more common DC voltages like 12V or 24V.
The LP-168HA is a 2.1-channel amp, which is what makes it popular
among pin cab builders. It's so difficult to find 2.1-channel options
that I think this one became popular by default. VirtuaPin used to
sell these as part of their speaker packages - they don't seem to
offer them any more, but you can easily find them on Amazon and eBay.
This has long been the go-to amp for most pin cab builders. I'm
afraid I haven't had good experiences with it, though. I've tried two
of them; the first one performed so badly that I assumed it was
defective, so I sent it back for a replacement, and that was just as
The problems I had with the Lepai were all with its audio quality. It
had a lot of background noise with no signal playing; it was too
underpowered to produce even modest volume levels with my 4" backbox
speakers; and the crossover basically didn't work (on either unit I
tried), making it almost impossible to get a proper volume balance on
the subwoofer - the sub would be either off or driven to total
distortion, with nothing in between. I've seen reports of the same
problems on the forums and Amazon reviews, so I tend to think these
reflect design flaws, but they could merely be common defects that
only affect some percentage of units.
To be fair, some people on the forums have said they're happy with
these amps, so I might have just had the bad luck to get two
particularly bad units.
If want to try the Lepai, be aware that there are a number of
identical looking units sold under very slightly different names, like
"Lepy" and "Lepei". I don't know if Lepai just can't decide how its
name ought to be rendered in a Western alphabet, or if the variations
are knockoffs (I'd say "cheap knockoffs", but the original was already
cheap). Maybe it's a mix of both. For what it's worth, I've talked
to a couple of people using the maybe-knockoff brands who were happier
with the results than I was with the (I assume) original brand.
Other packaged 2.1 amplifiers
There are a few other packaged 2.1-channel amplifiers, similar to the
Lepai above, available on Amazon and eBay. (By "packaged", I mean
that they come in enclosed cases, not just raw circuit boards like the
DIY amps mentioned earlier.) Some of them are newer designs based on
more powerful chips like the TPA3116D2, and I wouldn't be at all
surprised if at least a few of these are just repackaged versions of
the DIY boards. I haven't tested any of these myself.
Home stereo receivers
I don't know of anyone who's done this, but a home stereo receiver
could potentially be re-purposed as a pin cab amplifier. These tend
to have excellent sound quality, even the cheaper ones. The challenge
is that they tend to be much bigger than you could comfortably fit in
a pin cab.
Playfield effects speakers
In addition to the main backbox speakers, a separate set of speakers
can be placed inside the cabinet, usually under the TV where they
can't be seen, to reproduce "mechanical" sound effects - the sounds
made by things on the playfield, like the ball rolling around and
bumping into things, flippers flipping, bumpers bumping, and so on.
Newer versions of Visual Pinball have support for a "surround sound"
system for the playfield effects. This isn't quite the same as a home
theater surround sound setup, where you'd place speakers at the sides
and back of the room to create a 360° sound field that surrounds
the listener on all sides. For a pin cab, we borrow the same
multi-channel technology they use in home theaters, but instead of
using it to surround the listener, we use it to make the sound effects
sound like they're coming from specific points on the playfield. So
the thing we're "surrounding" is the playfield, not the listener. As
such, we place the speakers as shown above, at the corners of the
playfield area inside the cabinet.
Older versions of Visual Pinball (before 2017, when the surround
feature was added) had a more primitive version of the feature that
allowed you to play the mechanical effects through speakers in the
cab, but without the multi-channel capability. It at least created
the illusion that sounds were coming from the playfield area, but only
generally, since sounds couldn't be positioned in space the way they
can with four speakers.
To set up a surround-sound playfield effects system, you need:
- Four speakers
- Two 2-channel or 2.1-channel amplifiers
The playfield effects are just another set of audio channels, so at a
basic level, you just need another set of four speakers.
The best type of speaker for this job seems to be something called an
"exciter", also known as a tactile transducer or tactile subwoofer.
An exciter is like a speaker without the paper cone part. They're
designed to be attached to a rigid surface, and they work by making
that attached surface vibrate. The surface takes the place of the
paper cone in a normal speaker. In our case, the wall of the cabinet
serves as the surface.
One reason that exciters work well for this job is that they're
smaller than regular speakers. It's a lot easier to find space for
them in a cab. And they're designed to mount to a flat, rigid
surface, which is a perfect fit here, since we can use the side walls.
The other reason they're so good for this job is that they're
specifically designed to produce a tactile effect for low-frequency
sounds, which is precisely what we want from the playfield effects.
The playfield effects are all meant to simulate mechanical things on
the playfield moving and around and bumping into each other.
There are many options for exciters and tactile subwoofers available
online from Amazon and other Web sellers. I think any exciter that
gets decent user reviews on Amazon would be fine, since this isn't
exactly the most demanding audiophile scenario; these speakers are
mostly for percussion-type effects, not music or voices. So I'd
recommend doing a little research on Amazon to see what's currently
on offer. At the risk of listing equipment that may no longer be
available by the time you read this, here are some specific exciters
that forum members have mentioned favorably:
- Dayton DAEX25
- Dayton Audio DAEX25VT-4
- Dayton Audio DAEX58FP
You can use regular speakers if you prefer, but I don't think there
are any advantages. Regular speakers are larger and less tactile.
In the days before VP's surround sound support, some people set up
one- or two-speaker systems using their TV's built-in speakers. I
don't recommend this approach. Flat-panel TV speakers are invariably
small and tinny. They won't reproduce percussion-type effects with
You should use four identical speakers or exciters for the effects
speakers. This helps with the illusion of spatial positioning by
matching the tonal quality at each speaker as closely as possible.
For four speakers, you need four amplifier channels. This is in
addition to the amplifier(s) you're already using for the main backbox
speakers and subwoofer.
The usual setup is to add two more 2-channel or 2.1-channel
amplifiers. Use one for the front pair of exciters, and the other for
the rear pair.
I'd recommend using one of the DIY amplifier boards mentioned earlier,
as they're inexpensive and compact, and the ones based on newer chips
like the TPA3116D2 produce decent sound quality. I'm personally a lot
less picky about audio quality for these amps than for the main
backbox speaker amp, since these speakers are mostly for
percussion-type sound effects, not for music or voice effects.
Where to install the playfield effects speakers
For a four-speaker surround system, the speakers should go roughly
at the corners of the playfield TV.
Exciters are designed to mount on flat surfaces. The side walls of
the cabinet are perfect for this. I'd mount the exciters on the side
walls just below the TV, being sure to leave enough vertical clearance
for the TV.
Wiring the playfield effects speakers
The wiring plan for the playfield speakers is very similar to the plan
for the backbox speakers. The main difference is that we need two of
the 2-channel amps now, since we have four speakers on four separate
audio channels. It's most convenient to think of these as two pairs
of stereo speakers - a stereo pair at the front and a stereo pair at
the back. Each stereo pair connects to one of the amps, using the
normal Left/Right stereo hookups on the amps.
Key features to note:
- The Front output jack on the PC remains connected to the
main backbox speaker amplifier as before - make no changes to that
- Use two 2-channel amplifiers, one for the front left/right
speakers, and one for the rear left/right speakers
- The amplifier for the front speakers connects to the Rear Surround
audio jack on the PC
- Let me say that again, because it's too crazy to read right the
first time: the Front speakers plug into the Rear Surround jack
- The amp for the rear speakers connects to the Side Surround
audio jack on the PC
What's up with that bizarre wiring with the Front speakers
connected to the Rear surround jack on the PC? I know it
sounds crazy. The way to make sense of it is to think about the way
surround sound works in a home theater setup. The surround
sound feature in Windows is all designed around the home theater way
of thinking. Home theater people think in terms of a speaker layout
like this, with the listener at the center, and speakers placed
around the perimeter of the room:
This is how Windows sees the 7.1 audio format.
The format is designed with home theaters in mind, so it assumes
this particular spatial layout. This is an overhead view; the
figure at the center is the listener.
Windows is very attached to the idea that the speakers have this
specific spatial layout. When the Visual Pinball developers were
adding the surround sound feature, they had to work with that layout.
So how does this map onto a pin cab most easily? Like this:
So hopefully the twisted logic becomes more apparent now:
- Windows "Front Left" and "Front Right" = the main backbox speakers
- Windows "Center" = unused
- Windows "Side" = rear cabinet speakers (towards the back of the cab)
- Windows "Rear" = front cabinet speakers
Now we can see how we got to that confusing last element, where what
Windows calls "Rear" corresponds to what we think of as the front
of the cabinet. Remember that Windows thinks about this in home theater
terms, where the listener is in the middle of the picture, rather than
standing at one end. You have to picture the listener sitting somewhere
in the middle of the playfield for Windows's idea of "Side" and "Rear"
to make sense.
Also note that the "Front Center" speaker in the Windows layout isn't used
at all. We don't even connect a physical speaker there.
If this speaker were present, it would have to be situated right in
the middle of the speaker panel. We can't put a speaker there
because that's where the DMD (score display) goes.
Even if we could fit a speaker there, there wouldn't be any benefit
sonically, since the left and right speakers are so close together.
The center channel in the 7.1 audio format is intended for home
theater systems, where the front left/right speakers might be placed
six or eight feet apart. In that case, the sound field is so wide
that it's helpful to have an extra speaker in the middle, to keep
the dialog sounding like it's coming directly from the screen.
That extra degree of localization is pointless in a pinball setup,
since the left and right speakers are so close together that the ear
can't really localize sound to one or the other anyway.
Configuring Windows for playfield effects speakers
- Press Windows+R, type mmsys.cpl, press Enter
- Select the Playback tab
- Select your speakers from the list
- Click Configure
- Select 7.1 surround. Click Next.
- Check Side Pair and Rear Pair. Un-check Center.
Leave Subwoofer as before, according to how you set it up for the main backbox speakers.
- Leave the "full-range" settings as before, according to how you set it up
for the main backbox speakers. Click next.
- Click Next then click Finish
Configuring Visual Pinball for playfield effects speakers
- Launch Visual Pinball, without loading any game yet
- On the menu, select Preferences > Audio Options
- In the General output sound device, select your main sound card/speakers from the list.
It's better to select the device specifically rather than the default "Primary Sound Driver",
since that doesn't always work.
- In the Backglass specific Sound Device, select the same device
- In the Multi-channel output section, select 7.1 Surround
If that little homage to Orwell saying "Front is rear, black is white,
war is peace" that you see in the parentheses after "7.1 Surround"
seems confusing, it's because VP is trying to explain the whole speaker
layout in 10 words or less to fit the dialog box. Here's what it's
trying to say:
- Your pin cab's main backbox speakers connect to the PC audio "Front" output jack
- Rear playfield effects speakers connect to the PC "Side Surround" output jack
- Front playfield effects speakers connect to the PC "Rear Surround" output jack
This can seem backwards at first glance, but it makes a kind of sense
when you take into account how Windows thinks about surround sound.
The section above on wiring the effects speakers has a more detailed
explanation of the Windows surround sound model and why the
connections have to be arranged like this.
Editing Visual Pinball games to send sounds to the backbox speakers
If you have playfield effects speakers set up and configured in
Visual Pinball, VP's rule for deciding when to use which speakers
is really simple:
- If the sound comes from the game's ROM (the original game's
software, being emulated in VPinMAME), it's played through the backbox
- Otherwise, it's played through the playfield effects speakers
That rule usually does exactly what you want, because almost all of
the sound effects that aren't from the ROM are meant to simulate
something mechanical on the playfield. In some cases, though, you
might prefer for some of the non-ROM sounds to be played through the
backbox speakers. This might be desirable, for example, if you're
adding your own extra music or voice effects to supplement the game's
original soundtrack. It might also be better for certain mechanical
effects, such as EM-era bells (which were often situated in the
backbox in the originals) or scoring reel sounds.
VP lets you override the rule on an effect-by-effect basis, so
that you can redirect specific sound effects to the backbox speakers.
See "How to play table sound effects through the backbox speakers"
in Customizing VP Tables
Using playfield effects speakers instead of feedback devices
"Poor Man's DOF" or "Surround Sound Feedback" (PMD or SSF) refers to
using playfield speaker effects to replace all of the tactile feedback
effects that many cab builders implement with DOF using contactors,
solenoids, and the like. The main difference between this and the
basic playfield speaker setup is that some PMD/SSF builders add extra
exciters to strengthen the tactile effect, particularly at the front
of the machine where it's more noticeable. For example, some people
put an exciter under the lockbar, since that's where you rest your
hands while playing.
For more information, see the SSF group on Facebook:
I personally prefer discrete feedback devices for the solenoid
effects, as I find their audible and tactile effects more convincing
than audio recordings. I see playfield effects speakers as a great
complement to DOF, for other non-solenoid noises such as the ball
rolling and colliding with things. But the PMD/SSF approach is
attractive to some people for its lower cost and lower complexity.
Your amplifiers probably have volume knobs. But here's the problem:
do you think you're going to want to open up your cabinet and adjust
those knobs every time you want to turn the sound up or down?
Certainly not. You're going to want some kind of external volume
Pin cab builders over the years have come up with several ways to
approach this. Some of the early cab builders were stuck on the idea
that you had to use the volume knob to adjust loudness, so they came
up with ways to accomplish that without having to take apart the cab
- Situate the amplifier near the coin door, so that you can reach
in through the door and turn the knob
- Install the amplifier so that the knob actually sticks out
through a hole in the side of the cabinet, so that you can turn
the knob without even opening the door
- Install a remote-controlled motor that turns the knob for you when
you push buttons on the remote
My advice is to stop fixating on the volume knob, and use a whole
different approach: let Windows control the volume. Windows
has its own notion of the line output volume, which can be adjusted in
software. Doing it software means that you can control the volume
with the keyboard or mouse. That greatly simplifies the physical
controls, because you no longer have to worry about how to reach the
volume knob on the amplifier.
Pre-set the volume knob
To let Windows control the volume, the first step is to set a fixed
reference level for the volume controls on your amplifiers.
You'll turn the amplifier knob to this setting, and then just leave
it there from that point on. When you want to adjust how loud a
game sounds, you won't open up the cab and turn the knob.
You'll change the Windows volume level instead.
It's important to understand that the function of a volume knob on an
amplifier is turn down the power. An amplifier has an
intrinsic maximum power level, which is a function of the way it's
designed. If you didn't have the volume knob at all, the amplifier
would simply run at that maximum power level. The volume knob's
function is to reduce the power level from that maximum to whatever
lower level sounds right to you. When the volume knob is turned all
the way up, it means that you're letting the amp run at full power -
you're not attenuating the power at all.
So in principle, the fixed reference level for any amplifier should
simply be what you get when you turn the volume knob all the way up.
In practice, though, you usually don't want to do that. The problem
is that an amplifier amplifies not only the audio signal but also the
random background noise that's always present on the signal input.
When you turn the knob all the way to 10, the amplification is usually
so strong that it exaggerates the background noise, so that you hear a
constant loud hiss or buzz when there's no audio input signal playing.
So what you want to do is find a reference level that's as high as
possible, without producing excess hiss or buzz when the audio input
The procedure to find this level is pretty simple. Get everything
connected and turn on the amplifier. Make sure it's connected to the
PC output jack so that this is a fair test of normal playing
conditions, but make sure Windows isn't playing any sounds. Turn the
volume knob on the amp all the way down. Now turn it up slowly. Keep
going as long as the background noise coming out of the speakers
doesn't get excessive.
If you have a really good amplifier and good wiring, you might be able
to turn the knob all the way up, or very close, without excess noise.
To test that this setting is loud enough for normal use:
- Turn the Windows master volume level all the way down, using the
volume controls in the "system tray" at the bottom of the screen
- Play some sample music in your a media player, just to test the level
- Gradually turn up the Windows master volume until it's as loud as
the loudest level you'll likely want to use for pinball simulations
- If that's less than 100% on the Windows volume knob, you're done
- If you get to 100%, and it's still not loud enough, turn up the volume
on the physical volume knob on your amp until it's loud enough
- Turn the music off and re-check the background noise level coming
from the speakers. If it's acceptable, you're done.
- If there's too much noise at the new physical volume knob setting,
try turning the physical volume knob back down until the noise is
okay. Then repeat the music test.
- You might have to repeat the loud/quiet test a few times to find the
optimal balance between "loud enough" and "quiet enough". Some of the
cheapie 2.1 amplifiers and DIY amps can be pretty noisy when turned up
to high volumes, so you might have to put up with a certain amount of
background noise to get enough loudness at the high end. Or,
conversely, you might have to accept a limit on maximum loudness to
make it quiet enough.
I wrote a little utility program called PinVol that helps with audio
volume management, specifically for pin cabs. It's free and
open-source. Find out more about it here:
PinVol lets you assign any keyboard keys or joystick buttons to serve
as volume controls. It also has the notion of a "global" volume level
and a separate "local" volume level for each table, which is designed
to help you equalize the the loudness level across different tables.
Some VP tables are much louder than others. PinVol remembers the
per-table volume setting for each table and automatically restores it
each time you run a table, so that you don't have to keep manually
changing the volume level every time you switch tables (which I found
myself doing constantly, because of the big variations in loudness
from one table to the next).
With PinVol, you can assign different keys to control different
aspects of the volume:
- "Global" volume keys to control the system-wide volume
- "Local" volume keys to control just the volume level for the current table
- Global mute, to silence all audio effects
Set up physical buttons for controlling the volume
The next piece of the puzzle for controlling the volume through
Windows is to set up some physical controls to adjust the Windows
If you're not using PinVol, you typically just need two or three
buttons: Volume Up, Volume Down, and Mute.
If you're using PinVol, you'll want at least four buttons: Global
Volume Up, Global Volume Down, Local Volume Up, and Local Volume Down.
You might also want a Mute button and/or a Night Mode button.
There are several common options for setting up physical buttons:
- If you're using the Pinscape Controller or an i-Pac as your key
encoder, you can use "shifted" buttons for the volume controls.
Shifted buttons let you assign two separate functions to each physical
button - a normal function and a "shifted" function. The shifted
function is engaged by holding down another button - the Shift button
- and pressing the first button.
For example, I use the Extra Ball button as my Shift button,
and I use the shifted flipper and MagnaSave buttons as my
volume controls. The flipper buttons are just flipper buttons
most of the time, but when I hold down the Extra Ball button,
my right MagnaSave/Flipper buttons become the Table Volume Up/Down
buttons, and the left ones become the Global Volume Up/Down
buttons. I find that pairing the buttons on each side as
an Up/Down pair is intuitive and easy to use.
This is my favorite approach because it's so convenient
and it doesn't require any additional physical controls. To
set this up in the Pinscape Config Tool, go to the button
assignment section, and read the on-screen instructions for
setting up a Shift button.
- Add a rotary encoder dial. This can be mounted anywhere a button
can be mounted, but it gives you a combined Up/Down control in one
small knob, so it's somewhat less conspicuous than a pair or trio of buttons.
Some dials can also act as a pushbutton when you press the knob, which makes
an intuitive place for the Mute button, giving you three controls in one.
See this thread on vpforums:
This is my second-favorite option after using "Shifted" buttons.
A lot of people consider it their top choice because a knob is
so natural as a volume control. The only reason I rank it
second-best is that it is, after all, another control.
- Add some more front-panel pushbuttons, of the same type as the Start
and Exit buttons. Most people don't like doing this because of the
excess clutter, but you can mitigate the clutter by using smaller
buttons or small rocker switches, and you might be able to hide
them somewhat by installing them in the coin door, which is pretty
good at hiding things because it's matte black.
- Add pushbuttons or small rocker switches on the bottom of the
cabinet. This is nicely hidden, but it's also less convenient to
- Add controls inside the coin door. This is also nicely hidden,
but it's even less convenient to access than bottom controls.
Software setup for volume controls
The last step in setting up software volume control is to map the
physical buttons on your cabinet that you've designated as the volume
controls so that they trigger the Windows master volume adjustments.
If you're not using PinVol, the easy way to do this is to the
assign buttons to the special keyboard keys Media Volume Up,
Media Volume Down, and optionally Media Mute. These are
standard keys on a USB keyboard, and your key encoder will hopefully
include them among the keys you can assign to buttons. Windows
automatically recognizes these keys and uses them to adjust the master
volume control in the system tray, so you don't have to do anything
special in your Windows setup - these keys should just work
automatically as soon as you assign them to buttons.
If you're using the Pinscape Controller as your key encoder, you can
find these keys here on the little mini-keyboard that pops up when you
assign keys in the Config Tool:
For other key encoders, look for similar icons, or look for the key
names Volume Up, Volume Down, and Mute.
If you're using PinVol, you can assign any keys or joystick
buttons as the volume controls. PinVol shows instructions in its main
window for assigning the desired keys. Just follow the on-screen
If you're using a Pinscape Controller for button input, I recommend
assigning high-numbered "F" keys, like F14 through F20, for the PinVol
hot keys. The PinVol hot keys are global to the entire Windows
system, which means that once they're assigned to PinVol, other
applications won't be able to use them. The high-numbered "F" keys
are a good choice for this because I've never seen any applications
use them as default key mappings, so they shouldn't conflict with
anything else you're running. Here's the procedure to map them:
- Run the Pinscape Config Tool
- Go to the Settings screen
- Scroll down to the button assignments section
- Assign each button input for a volume control button to the desired
keyboard key or joystick button
- Save settings and exit the config tool
- Run PinVol
- Click in one of the key assignment boxes ("Global Volume Up", etc)
- Press the button you want to assign to that function
- Repeat for each button