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HDTV Audio Upgrade - G4 Harmon Kardon M6531 - Lepai vs Lepy

Posted: Wed Mar 20, 2013 3:56 pm
G4 Apple Pro Harman Kardon M6531 Speakers Mod

2nd Reply - Harman Kardon iSub 2000 SoundStick II
4th Reply - Adding Amplified Speakers to the HDTV
Next Page - Lepai LP-220A+ Amp vs Lepy LP-220A-3A Amp

Replace the plain square speakers of your PC or Mac with an inexpensive amp and eye catching crystal ball M6531 full audio range speakers. In the second Reply, the Harman Kardon SoundStick II does not need a mod, a simple plug into the audio output.


Most newer PCs come with LCD monitors with built in speakers. Sometimes the built in speakers do not produce a full frequency range of sound due the thin design enclosed inside the narrow LCD. External speaker computer systems are usually two square speakers on each side of the screen. To enhance the sound quality, either setup can be supplemented with a separate subwoofer speaker box, but taking up more of the limited space at the desk.

The Mac G4 computer came with high quality Apple Pro Harman Kardon Speakers part number M6531. These speakers are well built with a metal coned center surrounded by not foam, but by a very heavy duty rubber diaphragm offering a full range of sound. Due to an unusual four pin shielded proprietary plug designed just for the older Mac G4 computer, the speakers can be purchased at a low price at certain outlets and even online at a discount. I bought a set of the M6531 round speakers at the Swap Meet for five bucks. In the next Reply I posted a used Soundstick and iSub speaker set bought at a good price.

A desk of vintage Apple crystals - Right Click for larger view of picture

Power Mac G4 Cube, Harman Kardon SoundSticks, iSub woofer and crystal ball M6531 speakers.


Power - 20 watts (10 watts/channel)
Frequency - 70 hertz to 20 kilohertz.
Cable - 7" from Y-Adapter to speakers; 3" from Y-Adapter
2.5mm four pin shielded Plug - Apple proprietary 1/8" TRRS connector


Cut the cord
The Pro speaker proprietary plug is unique, very difficult to find an adapter for a regular stereo hookup. Right above the plug is a Y connection that houses a small chip. It is not an amplifier, just a detection logic chip that tells the G4 Apple that the speakers are plugged in.

Detection Logic Chip - Red Positive / Black Ground
Speaker 1 - White Positive / Blue Negative
Speaker 2 - Brown Positive / Yellow Negative

The speaker wires just pass thru the Y adapter so it can remain or be cut off along with the four pin shielded end plug. At first I soldered in a standard 3.5mm stereo plug to see how the speakers would sound on a portable music player and my iMac at the headphone jack. As expected, the sound was not very loud since the speakers do not have a built in amplifier.

I desoldered the 3.5mm plug to keep the speaker wires as long as possible. The headphone test was actually worthwhile doing for a couple of reasons.
1. Verifies both speakers still function before investing in an amplifier.
2. Apple products use ridiculously thin wire, the solder on the end wire is more durable.

Lepai LP-220A+ Amp
After verifying the speakers worked, it was time to pick up an amplifier. Most stereo amps are too bulky, even bookshelf models take up too much room on the desk top. In addition, the power output did not have to be outrageously huge since this is for a computer desk. The Lepai Amp fits the bill nicely, it can be found online for around twenty bucks.

IC Tripath TA2020-20
Output 2 x 20w @4ohm, 2 x 12W @ 8ohm
Signal to Noise Ratio SNR 98dB
Dynamic range 98dB
IHF-IM Distortion 0.1% @1W 4ohm
THD distortion
0.03% @9W 4ohm
0.1% @6W 8ohm
10% @13W 8ohm
12 volt 2 amp Power Plug

Dimensions 4.7 x 5.8 x 1.7 inches, a foot print about the size of an iPhone!


Note the blue light circling the volume control. The Lepai 220 which requires a 12 volt source can also be used as a light duty car amp. A 3.5mm double male ended stereo lead or audio RCA cables will also be needed to connect the PC to the amp. On the output side are the standard Spring Clip terminals for connecting speakers. Pretinned soldered speaker wire ends make for an easier and durable fit. :idea:


Play It Loud
I played some MP3s as well as a few games, very impressed with the sound quality of the speakers and amp. The speakers have a beveled base in the crystal housing pointing the sound up at just the right angle, directed even with the point of view of the monitor. Pressing the Tone button and cranking the Treble and Bass controls to max kicks up the range, this setup is crystal clear LOUD. The compact size of the shiny aluminum cased amp matched perfectly with the Apple Pro speakers. This is an inexpensive under thirty dollar investment to get a very decent and eye catching sound system for the Desktop. The tiny amp fits perfect right under the monitor or can be used in conjunction with a portable music player such as an iPod or Walkman. All the cable connections are hidden in the back out of the way. The Power, Treble, Bass and Volume (which lights up in blue) controls are solid in construction and all in front for an easy reach :mrgreen:

Identify unmarked speaker terminals
rafael wrote: ... er/11399/1

Find out the proper polarity of the speakers, i.e. which cable is negative (-) and which is positive (+).


Connect one wire to the negative terminal (-) and the other to the positive terminal (+) of the AA battery. If the speaker cone bulges out (left image), you've got the proper polarity. You now know that the wire on the positive terminal of the AA battery is your "+" wire, i.e. it will connect with the "+" output of your amp. If the speaker cone moves in (right image), the polarity is reversed. You now know that the wire on the negative terminal of the AA battery would be your "+" wire, i.e. it will connect with the "+" output of your amp.


Harmon Karmon Wiki -
Power Mac G4 Cube
Mac Forum - ... apter.html
Proprietarily Ridiculous - ... ulous.html
Apple Speakers with Class-D Amp - ... er/11399/1
Desktop stereo under $70 - ... under-$70/
Lepai Amp CNet Review - ... 90789.html
Lepai Amp FF Electronic Review
TA2020 Data Sheet -
Harmon Kardon iSub -

Amazon Lepai Amp - ... B0049P6OTI
Amazon M6531 Pro Speaker - ... B00V24ZZIU
EBay M6531 Pro Speaker - ... 1&_sacat=0

G4 Harmon Kardon Speaker Mod / SoundStick II

Posted: Sat Jun 22, 2013 6:57 pm
Harman Kardon iSub 2000 SoundStick II
A step up from the G4 Pro M6531 speakers, the SoundStick set was first introduced in 2000. Co-designed with Apple, Harman Kardon speakers have been produced before inside the Apple iMac G3 CRT desktop models. It has a built in amp and a standard audio connector; no mod is needed for use in other systems. There are some models that have a USB input that would need modded for standard audio output. The newest Harman Kardon Soundstick III is still produced today and has the same 3.5mm stereo audio connection of the early models.


Amazon wrote:Product Description From the Manufacturer
Praised for its stunning design, the Harman Kardon® SoundSticks II speakers and subwoofer system became a milestone in Harman Kardon history when it became part of the permanent collection at New York City's Museum of Modern Art (MoMA).

Crystal Clear Design
Tailored to match the clear housings of the Power Mac G4 systems, the speakers really have a futuristic look about them. Even today, they stand out compared to most other more conventially designed speakers. The design still holds well, the SoundStick can still be bought today brand new. Karmon Hardon currently manufactures a SoundStick III set which also supports USB for the audio connection.


Macworld wrote:

The subwoofer unit, 10.2 inches tall and 9.2 inches in diameter, remains, so many years after its introduction, stunning in its appearance: the completely clear enclosure looks more like a marine jelly than a speaker housing, with a torus-like top that hosts the unit’s bass port. Inside is a 6-inch driver backed by 20 Watts of power. In the back, near the bottom, is a blue light that furthers the underwater-like appearance—sitting in the dark, under a desk, the SoundsSticks II’s subwoofer unit brings to mind a backlit jelly swimming in a Discovery Channel video.

The two satellites look much like large, glass test tubes, 10 inches tall and 2 inches in diameter. But instead of hosting a single driver, or two drivers of different sizes, like most satellite speakers, each of the SoundSticks II's satellites sports four drivers, each one inch across. The system provides 10 Watts of power to each satellite, and the satellite enclosures are, like the sub, ported to enhance lower-frequency response.

Each satellite is connected to its base using a clever metal hinge that lets you swivel the speaker’s body back and down, to any angle from vertical to horizontal. This allows you to position the speaker so the drivers are aimed directly at your ears—providing the best treble performance—regardless of how low your desk is. The hinge is easy to reposition, but tight enough to hold at any angle.

The SoundSticks II is a 2.1 speaker system, which means it uses smaller left and right satellites for higher frequencies along with a larger subwoofer/amplifier component for lower frequencies. Nothing special there. But the SoundSticks II’s curves and shapes are truly unique, as are its transparent-plastic shells, which let you view everything inside—wires, transistors, you name it.


Wire Hookup
The larger woofer is the central point for all the wire connections. It also houses a built in amplifier.

1. Power lead - 3 pin proprietary connection
2. Left Speaker - Standard RCA connection
3. Right Speaker proprietary 4 pin connection
4. Stereo Input - 3.5mm Standard Mini Stereo connection


The stereo 3.5mm connector plugs into any regular Mini Headphone/Earbud analog audio jack of the PC or iPod music player. The standard plug makes it easy to accept any analog audio output. It can also be use with RCA adapters. Add an audio select switch box to expand on using multiple sound sources. A more common inexpensive composite video switchbox can be substituted, just use the two audio connectors. :idea:

Image Image

There is a volume control next to the wire connectors on the woofer housing. This only works as an alternate volume balance control to kick the bass louder or softer. When I first tried the SoundStick Speakers, I could only get a blue power light and no sound. Unplugging the power or a speaker connection produce a very faint pop sound out of the satellite speakers attesting that it seemed to be working. It was then I became curious about the wire connections. There must be a reason why one of the separate speakers did not have a standard RCA, but a four pin plug. Why the extra two wires, did the satellite speaker have some sort of built in smaller amp? It was then I noticed a slight difference between the two side speakers.

Note the small shiny metal tabs on the bottom of the left speaker

CRTGAMER wrote:Hidden Volume Control
The right hand satellite speaker has two shiny metal tabs at the base. At first it just seems to be a design accenting the crystal housing. Turns out these control the main amp located in the woofer housing!

LEFT METAL TAB - Volume Down
BOTH METAL TABS - Mute On and Off

Due to the "Hidden" volume control, the Soundstick might be perceived as defective leading to a low price at the Thrift Store or Swap meet. This can lead to a bargain for a knowledgable buyer.

One thing lacking is a dedicated power switch. I could have added a basic power switch in the base, but I also wanted a simple way to disconnect the rare power supply when not in use. A regular Power Strip would be bulky and have excess cord showing. However, a Remote Switch Office Cord did the trick and can be set next to the audio select switch box. What really surprised me is when the power is killed, the volume setting retains "memory", the same level of loudness is heard when the SoundStick is powered back on. :idea:

The Harmon Kardon SoundStick II is not going to break windows, but it is plenty loud for a nice thunder that you can feel. This is a great speaker set to give your PC system a nice custom look. This can work for iPod users for a clean home stereo speaker set that does not need a separate amp. I found a great use for this as a decent add on sound system for the bedroom TV. Hooked up to my "backup" HD CRT the combination produces great sounds emenating from all over the room. I was worried the woofer would drag all the sounds to the middle, but it really compliments the two satellite speakers separation of the stereo affect. Add in an audio input selector switch to connect various audio sources. I played a CD in a portable player wired into the SoundSticks and heard the same affect as a decent set of Headphones. You cannot tell where the sound is pinpointed from, yet still have that great "surround" separation. :mrgreen:

Wiki -
Power Mac G4 -
Specifications PDF - ... csheet.pdf
Setup Guide PDF -
Amazon Soundstick III - ... B0042F3K9W
Amazon Remote Switch Office Cord - ... B000GAS3HG
Macworld Review -
PC Mag Review -,2817,1556151,00.asp
Harmon Kardon SoundStick III - ... Qgodzj8AFQ

Right Click for a larger view

Harmon Kardon iSubwoofer 2000  Soundstick II 5330.jpg
Harmon Kardon iSubwoofer 2000 Soundstick II 5330.jpg (253.2 KiB) Viewed 22278 times

Re: G4 Harmon Kardon Speaker Mod / SoundStick II

Posted: Sat Jun 22, 2013 9:41 pm
by shallowgamer
Strong work! I'll endorse the lepai amp as well. I ditched the standard issue pc speakers and I'm using that same lepai amp with a JBL bookshelf pair. My God, what a world of difference. Now I use my PC for entertaining without tying up my receiver.

G4 Harmon Kardon M6531 - SoundStick II - HDTV Audio Upgrade

Posted: Wed Jul 10, 2013 3:40 pm
HDTV Audio Upgrade - External Speakers
External Amp and keep the HDTV Internal Speakers working

See the previous posts above for some unique speakers and amp attachments.

The right High Definition TV or even a Standard Definition TV can really enhance a game console or watching a movie. However, all the audio is heard from the TV at the front of the room. Supplementing the big screen with a Surround Sound Bar helps, but all the sounds are still located at the front of the room.


Most Sound Bars 2.1 placement for the HDTV are usually wireless, it could easily be relocated on the back wall for a better sound separation. This could have its own drawback since all the speakers are behind and not at each side of a TV viewer.

Adding a dedicated 5.1 Surround Sound Amp with matched speakers vastly improves the sound separation. This allows speakers at each corner of the room. However, the Woofer Box tends to be bulky and many times not placed correctly. Most setups tend to place that large woofer box under the TV which leads back to the audio mostly coming from the front of the room.

Surround Sound 5.1 vs 7.1 Speaker Placement
The rear speakers on a surround sound system tend to be on the small side, again leading to most of the sounds emanating from the front of the room. Adding two more speakers to the back as in a 7.1 Surround Sound system evens out the sound all around the room.


All the extra speakers really are not needed, especially if a home stereo is already set up. Use the existing stereo supplemented by the TV speakers to achieve decent sound controlled by the TV remote.

Most Home Theaters have the HDTV internal speakers turned off when using an external Surround Sound system. This is a waste if the HDTV has decent speakers, especially TVs that have an extra internal surround sound speaker inside such as the WEGA series. A CRT has this advantage over a flat LCD in the sound department, plenty of room inside for the "bose reflex" woofer.


Speaker Placement - Existing Home Stereo
Ideally there should be a minimal of four speakers at each corner of the room. The front is already handled by the HDTV. Although not at the corners of the room, the speakers are separated by the view screen. Instead of adding a separate Amp, the existing Home Stereo can be brought into play. If not done already, the speakers should be placed on either side of the couch. This works better if "bookshelf" speakers are utilized which can be placed on shelves above both sides of the couch at the back of the room.

The iSub Woofer and Soundsticks posted in the above reply can also work in place of the home stereo. Though not as loud as a regular amp, it could be enough when supplemented with the HDTV speakers. The Soundsticks with iSub Woofer are more compact then a home stereo; amplified speakers make a better choice for the bedroom or dorm home theater setup. Amplified speakers normally have a 1/8 inch audio plug, this can easily be connected to the RCA connection at the back of the TV with a set of adapter cables.


Audio Cable Connection
I am focusing on analog RCA connections for this Guide. The same speaker placement and sound utilization layout applies to the superior Digital Audio Hookup if your Home Theater supports it.

Almost all stereo amplifiers have an Auxilary Audio input. Amplified Speakers will usually have a 1/8"" mini stereo jack. Either can be used connected to the Audio Output of the HDTV. Note the connection options in the picture below, there are actually two sets of RCA audio connections that can be used.


1. Audio Output
2. Monitor Out (Audio Jacks)

For the Sony WEGA, the connections listed above each have an advantage and disadvantage. I mentioned earlier in maintaining audio to the HDTV internal speakers. There is also an issue of fade control in balancing the sound out. The TV can balance the volume from left or right, but not front to rear. This is accomplished by presetting the amp to a given level. However, as the TV volume is turned up or down then the front to rear balance is not consistent.

Sony KV32HV600 Audio Menu Speaker Setting.jpg
Sony KV32HV600 Audio Menu Speaker Setting.jpg (144.98 KiB) Viewed 21918 times

Menu - Audio Out Fixed
This gives full sound output to the external amp, but the HDTV internal speakers are disabled. Use this setting for a dedicated full Surround Sound external speaker system. This Menu setting would be a waste if the HDTV already has decent internal speakers.

Menu - Audio Out Variable - Internal Speakers Work! :idea:
Although the owners manual is not clear, the WEGA internal speakers can be combined with external speakers using the variable setting! The audio to the amp is reduced, so you will have to compensate the sound balance by turning up the amp volume control.

1. Temporarily turn the (TV) Speaker Off.
2. Select Audio Out to Variable.
3. Turn (TV) Speaker back on.

The gain here is both the HDTV Internal and External Speaker volume level are both equally controlled by the Remote, no need to compensate the Fade control. All connection sources work including RF, Composite, SVideo, Component and DVI/HDMI.

However, the Variable Audio Out may not be the perfect solution if the external amp is not powerful enough. This can be a factor with smaller amplified computer speakers.

RCA Monitor Out
Normally used as a second composite monitor for viewing and includes additional audio output jacks. It is an ideal connection when you want the full volume feeding an external amp and still maintain volume control on the WEGA internal speakers. However, only the RF, Composite and SVideo sends an audio feed to the Monitor Out. No audio can be heard from either Component or HDMI/DVI sources.

All Speakers Full Sound Component
The workaround is running a direct connection from any DVD player or Game Console that utilizes a Component connection. To maintain audio to the HDTV internal speakers, a couple of RCA Y adapter cables allow both the TV Component Audio Input and External Amp connections.
Add a RCA Selector box to isolate each of the audio signals going to the external amp. Any composite switch box will work, just use the Audio RCA jacks.

1. Monitor Out Audio Jacks to Switchbox
2. Component Input Audio Jacks Y Cable to Switchbox
3. Switchbox to External Amp or Powered Speakers


A more common Composite Video Switchbox can also be used, just use the two audio jacks. I prefer a non powered audio switcher since it is a little more compact. Either Switchbox allows full volume going to the external amp or powered speakers. The Speaker Switchbox normally is set to receive the Monitor Out signal for most TV viewing. If a Component Console or Component DVD Player is used, switch to that selection on the Speaker Switchbox.

Even with the add on amplified external speakers, the HDTV internal speakers still function just fine with the volume controlled by the remote. Due to the WEGA having an internal surround sound speaker I have a close proximate to the 5.1 setup. Though no separate front to rear sound affect this method has great stereo separation. The larger existing stereo speakers over a 5.1 arrangement at the back of the room keeps the audio surrounding everywhere and not just blasting from the HDTV at the front. :mrgreen:

Speaker Placement - ... ement.html
Stereo Audio Source Selector - ... r=&spell=1

Re: G4 Harmon Kardon M6531 - SoundStick II - HDTV Audio Upgr

Posted: Mon Aug 05, 2013 12:37 am
by kmbr
This was intensely useful and timely. I had already picked up the amplifier, but was clueless about figuring out which wire was which on the speakers once I exposed them (they ARE ridiculously tiny). I had been putting the mod off for a few weeks till I saw your post today. Done! Its nice to have the speakers in use again, they sound great and they're nice to look at. Wish I could think of something similarly clever to do with the iMac!
Thank you,

Re: G4 Harmon Kardon M6531 - SoundStick II - HDTV Audio Upgr

Posted: Wed Aug 07, 2013 8:05 pm
kmbr wrote:This was intensely useful and timely. I had already picked up the amplifier, but was clueless about figuring out which wire was which on the speakers once I exposed them (they ARE ridiculously tiny). I had been putting the mod off for a few weeks till I saw your post today. Done! Its nice to have the speakers in use again, they sound great and they're nice to look at.

Wish I could think of something similarly clever to do with the iMac!

Thanks, glad to help! Which amp and can you post what you use it on, maybe include a picture?

I use my iMac CRT G3 as a browser, wrote most of my posts with it. You can easily upgrade your iMac to OSX 10.4. Very important to make sure it has the bios updated while you are still in OS9 to avoid a lockup. Taken a step further keep OS9 for the older Max games, the G3 can run both operating systems in one hard drive. Not only is it the last beautiful Mac CRT, but has the direct compatibilty for OS9 games! :idea:

Re: G4 Harmon Kardon M6531 - SoundStick II - HDTV Audio Upgr

Posted: Wed Aug 07, 2013 8:24 pm
by AppleQueso
I've used that Lepai amp before, it's pretty nice.

Some stuff you mentioned about 5.1 systems that I need to mention though:
1. Because of the way we perceive low frequency sounds, where you place a subwoofer has virtually zero effect on where the sound will seem to be coming from. Placement is important, but for acoustic reasons, not because of what direction it's coming from.

2. Any reciever worth a damn will have settings to adjust the volume of individual speakers to even the volume output. Upgrading the rear speakers (or adding more) just to make them louder is completely unnecessary, you should be upgrading them only to improve sound quality.

Re: G4 Harmon Kardon M6531 - SoundStick II - HDTV Audio Upgr

Posted: Wed Aug 07, 2013 10:33 pm
by Aar1012
Most people are going to talk about the audio guide but i want to say nice set up on the G4. That's a G4 Cube, isn't it?

I've only been big on old Apple Laptops. The PowerBook G3 was my favorite design but sadly it's too old for me to use now and my G4 iBook is a good work horse.

EDIT - Yep, it's a G4 Cube. You mentioned it in the post but I was too busy looking at the pictures.

Re: G4 Harmon Kardon M6531 - SoundStick II - HDTV Audio Upgr

Posted: Mon Aug 14, 2017 7:11 pm
Aar1012 wrote:Most people are going to talk about the audio guide but i want to say nice set up on the G4. That's a G4 Cube, isn't it?

I've only been big on old Apple Laptops. The PowerBook G3 was my favorite design but sadly it's too old for me to use now and my G4 iBook is a good work horse.

EDIT - Yep, it's a G4 Cube. You mentioned it in the post but I was too busy looking at the pictures.

The "Crystal Apple" apple era really a beautiful series. The Crystal Harmon Kardon Woofer and Soundstick is still sold today!

Re: HDTV Audio Upgrade - G4 Harmon Kardon M6531 - Lepai vs L

Posted: Mon Aug 14, 2017 7:11 pm
Bought a Lepy LP-220A which is the replacement for the Lepai LP-220A+. Review on the way.

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