Speaker Wiring: Bi-Amping or Bi-Wiring, Active and Passive Explained

Posted in Blog, Tech, Tutorial on March 4th, 2014 by Matt – 3 Comments

Two amplifiers driving a pair of speakers has got to be better than one, right? Well everything's not as logical as it first sounds in the world of audio. In many cases running two amplifiers (bi-amping) is a complete waste of an amplifier.

There's lots of information out there, but most of it is in long winded articles. Let's see if we can get the basics a little more clear with some diagrams.

I'll diagram out the three most common ways of connecting bi-ampable speakers: Bi-Wiring, Bi-Amping with a passive or no crossover, and Bi-Amping with an active crossover.

I'm going to assume you have a set of speakers that can be bi-amped or bi-wired. How do you know if you do? Look for two sets of terminals on the back of your speakers:

Bi-amp terminals on the back of Polk Monitor speakers.

Bi-amp terminals on the back of Polk Monitor speakers.

Each set of terminals connects to either the highs in the speaker (tweeters) or the lows in the speaker (woofers). In the picture above you can clearly see the terminal bridges installed. Terminal bridges allow you to connect bi-ampable speakers via a single speaker wire to your amplifier. Just as you would if you had non bi-ampable speakers.

First up we have bi-wiring. Bi-wiring is simply running two sets of wires to each speaker. Your first logical thought is that adding more wire will reduce resistance of the wire connecting speaker to the amp. Well yes, but the resistance of the wire is so small as to be negligable. Assuming you're using  decent speaker wire; Bi-wirings only benefit is wasting a length of wire. 


Bi-wiring uses twice as much wire compared to a normal connection.

Next up Passive Bi-Amping. Here's the real waste of power with no benefit. Hows that you ask? I mean double the power right? How can that go wrong? (Jeremy Clarkson voice) POWEEEEERRRR!!!

In this case both amps amplify the full range of frequencies, and that's the problem. As we talked about above one set of terminals is only wanting high frequencies for the tweeters. The other set of terminals only wants low frequencies for the woofers. To ensure that your tweeters aren't blown by low frequencies resistors and other electronics are installed to block all low the low frequencies on the tweeters connections. Half those amplified frequencies are never going to reach a speaker. The amplifier handling the tweeters is having all low frequencies blocked before they make it to the tweeter.  The same goes for the amplifier handling the woofers, half of its energy is never used, being blocked before the woofers. And I use half loosely. Woofers use more power as a percentage than tweeters, but the analogy stands (note the math on the diagram).


Passive biamping is the waste of a perfectly good amplifier.

Lastly we have Active Bi-Amping. Yes this one actually has a use, but the benefits may not be as great as you would hope. If your amplifier is powerful enough that it can cause the speakers to distort before the amp itself distorts, then you have zero reason for this setup. On the other hand if, in a normal wiring setup, your speakers can handle your amplifier at max level then you may see some benefit. But I'd argue the case of why purchase two weak amplifiers and not just buy one powerful amplifier in the first place?


The full power from each amplifier is being seen by the speakers.

And in this setup we come across the problem with the fact that tweeters need less power than woofers. So assuming you're using matching amplifiers (and they should match for even sound) for both the tweeters and woofers. When the amplifier on the woofers is at max levels, the amplifier at the tweeters will be at a considerable less level; a waste of power. But you say, "I'm not planning to max my amplifier out. That would be too loud..." then whats the point of having double the amplifiers if a single one supplies enough power for your comfortable listening level!?

If you still say (Jeremy Clarkson voice) "POWEEER!!!!" then by all means, bi-amp away.

I hope this sheds a little light on a sometimes counter intuitive concept. Comment below with your thoughts.

Looking for a super in-depth conversation? Try this AVSForum thread. 35 pages of discussion.

Setting up a VMware ESXi 4.1 Environment with a Dell PS4000x SAN using Software iSCSI, Multiple Paths and Jumbo Frames

Posted in Blog, Tech, Tutorial on March 8th, 2012 by Matt – Be the first to comment

Yea, that's a jumble of a title. This will be a brain dump of all the configuration I've done on our SAN environment. Looking back it seems so easy to configure, and I doubt that it would take me more than an hour or two to set up a whole new SAN environment from scratch. But since this was my first time, it took me a lot of reading and research. Here's a dump of what I've done:

Our environment:

Two Dell r710 servers: Each with four onboard NIC ports and two add-in Broadcom 5709s with two ports each. Each server has two internal hard disks in a RAID 1 (mirrored) array to boot ESXi off of. Booting directly from the SAN is an option I will explore at a later date. In our environment I already had one server hosting a few VMs off of internal storage including a VSphere server. This process was an upgrade to add a SAN and another server. A note: If I could do this over again I would NOT have purchased Broadcom 5709s in our servers. The main reason I got them was to offload all iSCSI traffic to the cards and use the hardware iSCSI initiators in VMware. Apparently 5709s support offloading of iSCSI but not with jumbo frames. After reading this article which benchmarks VMware with hardware iSCSI without jumbo frames against software iSCSI with jumbo frames I decided I would use the software iSCSI initiators.

One Dell PS4000x SAN: The SAN has two controllers each with three ports. One port is for management and is on our LAN. The other two are for SAN traffic. The controllers work in a Active/Standby configuration. The secondary controller simply mirrors the primary controllers configuration and sits idle until the primary controller fails, then the secondary takes over.

Two Cisco 3750G Switches: The pair are in a stacked configuration using Cisco's StackWise interconnects. These switches will ONLY be used for the SAN. Doing so saves a lot of VLAN configuration. At the moment I didn't even set VLAN information.

My process:

The following is how I set all this up. I used tons of various articles from official configuration guides to forum and blog posts. I'll try to link to the actual documents used wherever possible.

I rack mounted everything. I decided to go with the switches top most. Below that (with some space) our two servers. Below that (with some space) our SAN, Below that (with some space) two UPSs.

Install ESXi:

As stated earlier my environment already had one ESXi server running with VMs hosted out of internal storage including a VM hosting VSphere. I simply installed ESXi on the new server, wired it into the SAN/LAN and added it to VSphere. From there I managed everything. If I were doing this fresh (without a VSphere install) I'd install ESXi on both servers, connect all the SAN/LAN connections then connect to each one via a VSphere client  independently to configure the SAN connections then create a VSphere VM to manage them both.

Network Connections:

For redundancy each server should have at least two completely independent network routes to the SAN and LAN. In my situation each of my Dell servers have three independent network controllers. The two Broadcom cards and the onboard units. On each server I'm using one port on each of the two Broadcom cards for SAN connectivity. The SAN has two controller cards. Each card has two SAN ports and a management port. One SAN port from each card is connected to one switch and the Management ports are connected to the LAN.

Should any one network card on a server fail the sever will still have SAN and LAN access. Should any one of the switches fail the servers will have SAN and LAN access. Should any one of the SAN controllers fail the servers will have SAN and LAN access.

IP addresses for each device are in the range. The Dell SAN requires three IP address. One for each network port (.1 and .2) on a member and a group IP address (.10). The servers have two SAN IPs each (.3 .4 and .5 .6).

SAN Topology Diagram

SAN Topology Diagram: Blue is SAN connections. Green is LAN connections.

Configuring the Cisco 3750g Switches:

Following the Appendix F of the Dell EqualLogic Configuration Guide "Cisco IOS based Switch Configuration" I enabled portfast, enabled flow control, disabled unicast storm, and enabled jumbo frames. Once again I'm setting these options on all ports because these are dedicated SAN only switches. Also because my switches are stacked I can configure them both from the same connection. Your situation may differ.

Enabled portfast on all ports:

Switch# config terminal
Switch(config)# spanning-tree portfast default
Switch(config)# end
Switch# copy running-config startup-config

Enabled flow control:

Switch> enable
Switch# configure terminal
Switch(config)# interface range gi1/0/1 - 24
Switch(config-if)# flowcontrol receive desired
Switch(config-if)# exit
Switch(config)# interface range gi2/0/1 - 24
Switch(config-if)# flowcontrol receive desired
Switch(config-if)# exit
Switch(config)# exit
Switch# copy running-config startup-config

Disabled unicast storm control:

Switch> enable
Switch# configure terminal
Switch(config)# interface range gi1/0/1 - 24
Switch(config-if)# no storm-control unicast level
Switch(config-if)# exit
Switch(config)# interface range gi2/0/1 - 24
Switch(config-if)# no storm-control unicast level
Switch(config-if)# exit
Switch(config)# exit
Switch# copy running-config startup-config

Enabled Jumbo Frames (notice this requires a reload... don't do this if you're on production equipment!):

Switch> enable
Switch# config terminal
Switch(config)# system mtu jumbo 9000
Switch(config)# exit
Switch# copy running-config startup-config
Switch# reload

Then I verified all my settings:

Switch# show spanning-tree interface gi1/0/1
Switch# show flowcontrol interface gi1/0/1
Switch# show storm-control gi1/0/1 unicast
Switch# configure t
Switch(config)# show system mtu
Switch(config)# exit
Switch# show interface gigabitethernet1/0/1

The last command is to confirm and MTU of 9000 on the port. Repeat the previous commands on all ports to ensure they have the necessary settings.

Initialize the SAN:

First time use of the PS Series SANs require you to connect to the unit with a serial cable and run a initial configuration wizard. The PS4000 Installation and Setup Manual covers all these steps in more detail.

Hook up the serial cable and open a connection to whatever COM port you used. I used Putty for this. Hit enter and you should get a prompt. Type "setup" to start the configuration wizard. First time setup uses "grpadmin" for both the username and password. From here you'll br prompted to set up a member name, group name, IP address, password and a few other things. After this process completes you can connect in a web browser to the units management interface via the IP address you set. From there you can setup the RAID level and volumes. At this time I've chosen RAID 5, but since I'm currently not production with this unit I plan on reformatting it to RAID 6 and RAID 50 to test performance levels. A note: Once you've chosen a particular RAID level you can only change to similar RAID levels.

RAID-10: Can only be changed to RAID-50, RAID-6, or RAID-5
RAID-50: Can only be changed to RAID-6 or RAID-5
RAID-6: can only be changed to RAID-5

Should you want to make an unsupported RAID level change you need to pretty much start over with the SAN member. In a one member environment this means also starting over with the group. See this post by an EqualLogic employee.

After completing the initial setup, I connected to the SAN's LAN IP address and created a temporary volume. Having a volume ready to connect to makes it easier to know you've set up your ESXi iSCSI connections correctly.

Install the Dell MEM (Multipath Extension Module):

This module is an alternative to the built in VMware iSCSI path selectors. It's configured to better support the PS series controllers. Installation consists of downloading the Dell Multipath Extension Module then using one of three ways to install it to your ESX hosts. All of the following is taken from the Installation and User Guide that comes in the MEM download package. Note: No matter which method you choose your ESX host will need to be in maintenance mode.

I chose to install the module via the vSphere CLI that's available here. After installing the vSphere CLI, I extracted the contents of the Dell MEM download to the /bin directory in the CLI install. Then after launching the CLI and changing directory to the /bin directory ("cd bin") I ran the following:

esxcli --server=esxi1 software vib install --depot dell-eql-mem-esx4-

Then repeated the command for my other ESX server and took both servers out of maintenance mode.

Configuring ESXi SAN Connections with Jumbo Frames:

Most of the following I got from the VMware iSCSI SAN Configuration Guide however that guide doesn't cover jumbo frames. For Jumbo frames replace the commands in the previous guide with the commands from the Knowledge Base article: iSCSI and Jumbo Frames configuration on ESX/ESXi.

All of the guides say to do the steps straight from the terminal. However all of the steps can be accomplished remotely using the VMware CLI. The VMware CLI is a series of Perl scripts. According to the documentation you can simply type the scripts name then switches to launch them. However on my computer I needed to change to the /bin subdirectory of the CLI install (where the scripts are actually located) and call each script with its .pl extension. Since the guides commands all assume your at the console the "--server=servername" switch will needed to be added to all commands in the guides.

Create a vSwitch:

esxcfg-vswitch.pl --server=esxi1 -a vSwitch-iSCSI

Change the MTU to 9000 on the vSwitch:

esxcfg-vswitch.pl --server=esxi1 -m 9000 vSwitch-iSCSI

Create two VM kernal port groups for iSCSI traffic (because I have two SAN connections on this server):

esxcfg-vswitch.pl --server=esxi1 -A iSCSI1 vSwitch-iSCSI
esxcfg-vswitch.pl --server=esxi1 -A iSCSI2 vSwitch-iSCSI

Create two VM kernal connections (one for each port group) with jumbo frames:

esxcfg-vmknic.pl --server=esxi1 -a -i -n -m 9000 iSCSI1
esxcfg-vmknic.pl --server=esxi1 -a -i -n -m 9000 iSCSI2

Make a note of the port names assigned to these connections when you create them. The port name will be in the format of "vmk#". You can view the port name from the networking section under the configuration tab. In my case iSCSI1 was vmk1 and iSCSI2 was vmk2

Each VMKernal Port needs to be assigned to one physical adapter. By default since all ports on a switch can use all adapters on the switch. We need to change each port to ONLY use a particular adapter. To do so select Properties on the vSwitch we created. Select the first iSCSI port listed and hit the Edit button. On the NIC Teaming tab move all but one of the vmnic adapters to the Unused Adapters section. Repeat the process for the other iSCSI ports on the switch so that each iSCSI port is bound to only one Active Adapter.

Failover Override

Each iSCSI port must be assigned only one Active Adapter

Enable the Software iSCSI adapter now if you haven't. Log in to vSphere client, select your server, configuration tab, Storage Adapters, select the Software iSCSI Adapter (and make a note of its port name, e.g. vmhba#), click configure, select Enable. In my case the Software iSCSI Adapter was vmhba41.

Bind the iSCSI ports to the iSCSI adapters:

esxcli --server=esxi1 swiscsi nic add -n vmk1 -d vmhba41
esxcli --server=esxi1 swiscsi nic add -n vmk2 -d vmhba41

The last step is to set up our discovery address and scan the bus.  Under the Storage Adapter section of the Configuration tab select the Software iSCSI adapter, select Properties, select the Dynamic Discovery tab, select the Add button and input the IP address of our Dell SAN group, not the individual member, but the group. In our case the group IP was Select OK. When you hit close on the iSCSI Initiator Properties window you will be prompted to scan the bus. Select yes. If everything worked out correctly a new entry should populate under the iSCSI Storage Adapter details. Also if we navigate to the the Storage section we should see the volume we created earlier available for use.

An alternative to running each of the previous commands individually is to use the setup.pl script provided by Dell. We copied it over earlier to our vSphere CLI installation bin folder from the Dell MEM installation. Using the script consists of launching the vSphere CLI, changing into the /bin directory (only because thats where we extracted it earlier), and running the following:

setup.pl --configure --server=esxi1

The script will then prompt your for all the parameters we used earlier and setup everything automatically. It makes setup very easy. Have a look:

Dell's Setup Script

Dell's Setup Script - Click to Enlarge

Confirming Jumbo Frames are Being Used:

To confirm you are in fact using Jumbo frames and multiple paths you can connect to the Dell SAN's management interface via web browser, login, and go to the Monitoring section and select the Events list. You should see "iSCSI log on to target... stuff here... successfull, using Jumbo frame length."


Now you're up and running. If this was a fresh install I'd create myself a vSphere server VM and go to town.

Windows with two network connections: internal and external

Posted in Blog, Tech, Tutorial on May 6th, 2011 by Matt – 2 Comments

This post applies to both Windows 7 and Windows XP (and probably the server OS's as well).

At the office we have two available networks: An internal network with our servers that also has filtered internet and an external wifi network that just offers unfiltered internet.

The main issue is that, as an IT tech, I download a lot of large files that can slow down our network, so I often found myself using a laptop on our external wifi downloading items so that I don't slow internal people down.

My goal was to have two network connections on my Windows 7 PC, one wired internal connection and one a wifi external connection. I also want my internet traffic to go over my wifi connection but at the same time any have the ability to access all the internal sources.

A warning before I start: Doing this incorrectly can open a giant security hole in your network, please don't do it without the approval of your IT dept.

First, I simply hooked up both network connections and tested them both (by only plugging one in at a time and checking the internet) as fully functional.

Once both are functional you need to edit your routing table so the correct requests go over the correct network adapter.

You can do this via the command line, but I found the Nirsoft NetRouteView utility to make this whole process a whole bunch easier.

Download and extract the NetRouteView utility. Then if on Windows 7, right click the NetRouteView.exe file and select "Run as Administrator".

NetRouteView with two connections

Click the "Interface Name" column title to sort your entries by interface like above.

Depending on your network only one or two changes should be made. First, you need to remove the entry from your internal network. That entry is a "catch all". We want the catch all on the outside network and not the inside. So remove from your internal adapter and make sure its already there on your external connection.

For most people that should be it! But for me I had to add one entry to my internal network to get it to work. I wanted the whole (that means anything that has a 192 for its first number in it's IP address) to go on my internal network connection. So I added the following:

Adding a route

Adding a route

Thats it! To check that everything is going over the correct interface I added the Network Traffic gadget to my Windows 7 desktop twice (just drag it to the desktop twice from the gadget list). I made my internal connection red and my external connection green.

Network Traffic with two connections

Network Traffic with two connections

Now I can watch as I view a web page which adapter it's going out.

Redirecting Lotus Notes Data to a Network Share

Posted in Blog, Tutorial on January 11th, 2011 by Matt – 3 Comments

I currently redirect users' Lotus Notes data folder (the folder that contains their ID files as well as other personal files) to network shares. This allows for users to roam from computer to computer in our office and always have their data available. As far as IBM is concerned this is an unsupported configuration, they will not help you if you have issues. We're currently using the 8.5.1 client with FixPack 4 installed.

Preparing Users Data for the Network

The first step is to copy a users Data folder onto a network share. The location of the share should be the same for all users. For example; each of our users has a "home" drive mapped to H: where they store their personal documents. Under this drive we have a folder titled "lotus" that we place a copy of the contents of their Data folder.

After you've copied the contents to the network share, you'll need to edit the users notes.ini file thats located within that share. The line you'll need to change in that file is "Directory=C:\..." change it to the location where you've copied their data. In my situation I change that line to "Directory=H:\lotus"

Redirecting Lotus to Look in the Network Share

Now that we have our user data in a network location, we need to tell lotus to look there and not in the usual Data folder location. There are a couple of methods to do this. First is using a registry entry and the second is actually editing the shortcuts. In my experience the shortcut method has been much more reliable.

Registry method:
For each user add the following registry entry (maybe as part of a log on script)
[HKEY_CURRENT_USER\Software\Lotus\Notes\8.0] "NotesIniPath"="H:\\lotus\\notes.ini"

Redirecting via the Registry


Shortcut method:
Edit the shortcuts on the all users desktop and the start menu so the target line is as follows (quotation marks and all)
"C:\(Install location of Lotus Notes)\notes.exe" "=h:\lotus\notes.ini"

Redirecting via Editing Shortcuts

Some Notes (Get it?!)

Currently on Windows 7 I do a Single User Install of the Standard Client. I've found that if I do a multi-user install I get prompted for my ID password for ntaskldr.exe. Googling has not returned a way to correct this.

While this modification does allow users to roam between computers, they can not have more than one instance of Notes open at a time.

After you've successfully got Notes functioning redirected you can delete the Data directory from the local machine. As long as your redirects are in place, it will never be recreated.

My users are not administrators on their machines. A single user install by default stores the users Data folder in the Program Files directory, which a user can't write to. But since we're redirecting that folder to a writeable location the users never have any permission issues.

Thinning Down FireFox 4's Tab Bar - Update!

Posted in Blog, Tech, Tutorial on September 16th, 2010 by Matt – 11 Comments

This post is now outdated, please see the update available here:


My previous post about modifying FireFox 4's tab bar layout has been one of the more popular posts on my blog. After updating to FF4 Beta 6 the modification broke, but I've found a solution:

#navigator-toolbox[tabsontop="true"] #TabsToolbar{
padding-left: 80px !important;
padding-right: 102px !important;
padding-top: 2px !important;
margin-top: -25px !important;

padding: 3px 5px 3px 5px !important;
height: 20px !important;

As you can see, the only change is we tell the tab bar to move up 25 pixels from where it was. We also ditch the tab position as fixed as it's not really necessary.

FireFox 4 with a better tab layout

This gets us back to our old style. I haven't had time to test all the edge cases to see if it messes anything up, but it should get your normal browsing bar back to an acceptable size.

Finding out where a picture was taken using EXIF info

Posted in Blog, Random, Tech, Tutorial on August 18th, 2010 by Matt – 13 Comments

Alternate title: How to creepily stalk people using their pictures.

Since I've gotten an iPhone 4 I've stopped carrying a normal camera with me on outings. I find the iPhone's camera more than sufficient for most of my photo needs. Many other people are also doing the same. The fun thing about most camera phones now, is that they tag image information with GPS coordinates. Thanks to some easy online tools, you can now track people only by their pictures.

Lets get an example. I did a Google Search for "shots taken with my iPhone" and the first result is a blog with "9 Cracking Shots Taken With My iPhone". The second picture posted is a pic taken on a road supposedly in Death Valley. Lets see if it is.

A test image for GPS EXIF inforation

We can download a program to view where the photo was taken via its EXIF information. Programs like "Simple EXIF Viewer for Mac OSX" work well. Or you could install a FireFox extension like "EXIF Viewer", it's a very nice way to quickly view information for any image embedded on a web page. But both of these seem silly to install when you probably only need to view EXIF info once in a blue moon.

My new favorite way to view where photos were taken is to use online tools like "Jeffery's EXIF Viewer" or the "Find EXIF" website. So, using our example, we would: Right click the image, Copy Image Location, Paste the image location into one of the online tools. In this example I've used Jeffery's EXIF viewer that embeds a nice little Google Maps pin of where the image says it was taken. Results from the EXIF GPS information

And if you follow the links over to Google Maps, and drop a street view pin as close to GPS data as possible, you get this:

Results from the iPhone's GPS EXIF info

You can view the actual Google Street view location here. Pretty cool.

Fixing Windows XP CD Playback Stuttering and Skipping

Posted in Blog, Tech, Tutorial on July 12th, 2010 by Matt – Be the first to comment

One of our users has a HP desktop that was having issues playing audio from music CDs. The audio was constantly stuttering and skipping. I tried various software playback programs all with the same result.

The solution turned out to be a setting for the CD-Rom drive. The drive was configured to use PIO mode when it should be configured to use DMA mode. Switching to DMA mode resulted in smooth audio CD playback. Here's how to change the setting:

Solving Audio CD Suttering in Windows XP

The steps:

  1. Right Click on My computer, click Manage
  2. Select Device Manager from the list on the left
  3. Expand the IDE ATA secton
  4. Right click on each IDE Channel (you may have multiple Secondaries and Primaries), click Properties
  5. Select the Advanced Settings tab
    Change the Transfer Mode to DMA if Available under each device
  6. Repeat steps 4 & 5 for each Primary and Secondary IDE Channel
  7. Reboot your computer

That should resolve the Audio CD stuttering and skipping under Windows XP.

Thinning Down FireFox 4's Tab Bar

Posted in Blog, Tech, Tutorial on July 7th, 2010 by Matt – 64 Comments

This post is now outdated, please see the update here:


If you've read my rant on window layout in a widescreen world you'd know that I dislike wasted vertical space in my window layouts.

FireFox 4 beta has just been released and they haven't solved my pet issue... that silly title bar. Just look at the wasted screen real estate:

FireFox 4's Tab Layout

However, thanks to FireFox's flexibility, the addition of a few lines to one file can solve the problem! Simply adding the following below the @namespace line:

position: fixed !important;

#navigator-toolbox[tabsontop="true"] #TabsToolbar{
padding-left: 80px !important;
padding-right: 102px !important;
padding-top: 2px !important;

padding: 3px 5px 3px 5px !important;
height: 20px !important;

To your userChrome.css file, and you now get this wonderful layout:

FireFox 4 with a better tab layout


The userChrome.css file is located in the following locations:

XP: C:\Documents and Settings\<user>\Application Data\Mozilla\Firefox\Profiles\<profile>\chrome\
Vista\7: C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\chrome\

A note: This "fix" will look bad if you have FireFox set to not display that tab bar when you only have a single tab open. Just set FF to always show that tab bar to resolve the issue (FireFox Button > Options > Tabs > Always display tab bar).

EDIT: I changed a line in the navigation toolbox from margin-right to padding right. Using padding right gives a better look.