A Guide to Crossover Networks & Crossover Settings

[Big Daddy]

A GUIDE TO CROSSOVER NETWORKS

Prepared by Big Daddy

What is a Crossover Network?
A crossover splits frequencies so that each speaker receives a certain range of frequencies so that we do not exceed the capabilities of the speaker, reduce distortion, and avoid speaker damage.

Types of Crossover Filters
There are three types of crossovers: Low-Pass, High-Pass, and Band-Pass.

Low-Pass Filter: A low-pass filter blocks (attenuates) high frequency signals above the cutoff frequency and passes low-frequency signals. It is sometimes called a high-cut filter, or treble cut filter. Low-pass filters are generally used on subwoofers to block high frequency signals that they cannot reproduce.

High-Pass Filter: A high-pass filter blocks (attenuates) the low frequency signals below the cutoff frequency, but passes high frequency signals. It is sometimes called a low-cut filter.

Band-Pass Filter: A band-pass filter blocks (attenuates) frequency signals outside of a certain range and passes frequency signals within that range. These filters can be created by combining a low-pass filter with a high-pass filter into a single filter. The bandwidth of the filter is simply the difference between the upper and lower cutoff frequencies.

In physics, attenuation is the gradual loss in intensity of any kind through a medium.

Filter Characteristics
Crossovers do not block undesired frequencies completely. They cut frequencies progressively. You need two specifications for a crossover:

• The crossover frequency or the point at which the filter begins to work
• The slope or how quickly the filter sets block unwanted frequencies. A crossover slope describes how effective a crossover is in blocking frequencies. It is usually expressed in dB/octave.

Assume we have a two-way speaker with one woofer and one tweeter. The crossover frequency is simply the point at which the crossover begins to separate the high frequencies from the bass frequencies. For most two-way speakers, this frequency is set around 1 to 2kHz.

Let’s assume the low-pass crossover frequency in the two-way speaker is set at 1.5kHz. This does not mean that all the frequencies higher than 1.5 kHz go to the tweeter and everything lower goes to the woofer. As you can see in the following diagram, the high frequencies are reduced very gently.

Source: TheSpeakerCompany.com (Out of Business)

This is most probably a crossover network that has a slope of 6 dB/octave. This simply means that a frequency that is twice the cutoff frequency (i.e., 3 kHz) is reduced by 6 dB compared to a signal at 1.5 kHz. This is an example of a first-order filter.

There are many different types of filter circuits, with different responses to changing frequency. In all cases, at the cutoff frequency, the filter attenuates the input power by half or -3 dB. You should remember that when you want to increase the sound level by 3db, you will have to double the amplifier’s power.

A second-order filter (12 db/octave) attenuates higher frequencies more steeply. This means that a frequency twice as large as the cutoff frequency (i.e., 3kHz) is reduced by 12db.

A third-order filter has 18 dB/octave slope and a fourth-order filter has a slope of 24 db/octave. We rarely see slopes steeper than 24 dB/octave in loudspeaker crossovers.

Low order passive crossovers are not very expensive. Higher order (i.e., 24dB/octave) crossovers can get more expensive.

The following diagram demonstrates a third-order filter (18 dB/octave). Compare it to the first diagram to see how much faster this filter reduces or attenuates high frequencies.

Source: TheSpeakerCompany.com (Out of Business)

Just as our low pass filter keeps high frequencies away from the woofer, a high pass filter keeps low frequencies away from the tweeter. When we add a high pass filter to to a low-pass filter, the result looks like the following diagram:

Source: TheSpeakerCompany.com (Out of Business)



Source: Emusician

Symmetrical vs. Asymmetrical
If the slopes of both the low-pass filter and the high-pass filters are identical, we usually refer to the crossover as symmetrical. If, however, a crossover’s low pass filter has a slope of 6 dB/octave and the high pass slope is 12 dB/octave, we call it an asymmetrical crossover.

Two-Way and Three-Way
A two-way crossover splits the full range signal into two parts – lower and higher frequencies (low-pass and high-pass). A three way crossover splits the full range signal into three parts – low, middle, and high frequencies (low-pass, band-pass, and high-pass). Four- or five-way crossovers are increasingly rare nowadays.

A 2-way speaker has two independent components that are attached to a 2-way crossover network: a separate tweeter and a separate mid-range/woofer.

A 3-way sepaker has three independent components that are attached to a 3-way crossover network: a tweeter, a mid-range, and a woofer.

In most speaker drivers, a voice coil is a single coiled wire wrapped around a cylinder called a Former, produces the changing magnetic field when alternating current from the amplifier flows through it.

A dual voice coil driver is one in which two separate coils of wire are wound together around the same former and terminated independently.

The main advantage of a dual voice coil speaker is wiring flexibility. They are wired in series or parallel to increase or decrease impedance to deal with amplifiers that may not be able to handle different loads. Some believe that there is no need for this anymore as most modern amplifiers can deal with 2Ohm, 4Ohm, and 8Ohm loads without any problems.

This article by JL Audio. does a good description of dual voice coil.

Active and Passive Crossovers
There are two broad classification of crossovers, based on where the crossover is placed in the signal path.

Passive crossovers are the most common. These crossovers are not powered and are usually placed within a loudspeaker’s enclosure to direct an amplified signal to the appropriate drivers. The following diagram should make this clear.

Source: TheSpeakerCompany.com (Out of Business)

Active crossovers need power and have a cable to be plugged into the wall. They split the full range signal before it gets to an amplifier and sends them to the appropriate amplifiers to drive the speakers. These type of crossovers are sometimes called electronic crossovers. Active crossovers can be implemented digitally using a DSP chip or a microprocessor. These are the type you find on powered subwoofers and inside A/V receivers.

Source: TheSpeakerCompany.com (Out of Business)


BASIC ELECTRONIC COMPONENTS

Inductor
An inductor (L) is a passive electrical component that can store energy in a magnetic field created by the electric current passing through it. The unit of inductance is Henry (H). The following diagram demonstrates some basic inductors.

Source: Wikipedia

Capacitor
A capacitor (C) is a passive electrical component consisting of an insulating (dielectric) layer between two conductors. When a voltage potential difference occurs between the conductors, an electric field occurs in the insulator. This field can be used to store energy. The effect is greatest between wide, flat, parallel, narrowly separated conductors. The unit of capacitance is Farad (F). Some basic capacitors are demonstrated in the following diagram.

Source: Wikipedia

Resistor
A resistor (R) is a two-terminal passive electronic component designed to oppose an electric current by creating a voltage drop between its terminals. From Ohm’s law, the resistance is equal to Voltage divided by current: R = V / I. The unit of resistane is Ohm (Ω). Some basic resistors are demonstrated in the following diagram.

Source: Wikipedia


TYPES OF CIRCUITS

The fundamental passive linear circuit elements mentioned above can be combined to form an electrical circuit in four distinct ways: the RC circuit, the RL circuit, the LC circuit, and the RLC circuit. These circuits exhibit important types of behavior that enable them to act as passive crossover filters.

Passive Crossovers are capacitors and inductors either in parallel or series, or combinations that are added to cut off high or low frequencies.

A capacitor stores voltage and blocks off signal at lower frequencies, and acts as a short (lets signal pass through) at higher frequencies. If a capacitor is hooked up in series with a speaker, it will act as a high-pass filter.

An inductor, on the other hand, stores current and acts in exact opposite way of a capacitor. Inductors act as shorts (lets signal pass through) at lower frequencies, and blocks off high frequencies. If an inductor is hooked up in series with a speaker, it will act as a low-pass filter.

Subwoofers need inductors in series to act as low-pass filters to block high frequencies. Mid-range drivers need both a high-pass and a low-pass (band-pass). Tweeters need only high-pass filters to block lower frequencies. The following diagrams demonstrate the different types of passive crossover filters.

Examples of Crossover Filters
The simplest low-pass filter has an inductor(resistor) in series and a capacitor in parallel to the speaker. The following figure shows a low-pass RC filter:

Source: Created by Big Daddy

The simplest high-pass crossover filter consists of a capacitor in series and an inductor (resistor) in parallel with the signal path.

Source: Created by Big Daddy

A band-pass filter is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. An example of a band-pass filter is an RLC circuit (a resistor–inductor–capacitor circuit). These filters can also be created by combining a low-pass filter with a high-pass filter.

Source: AllAboutCircuits.com



Source: Created by Big Daddy

There are different ways of designing crossover networks. The most common designs are: Butterworth, Linkwitz-Riley, Bessel, and Chebyshev. The following diagrams demonstrate the Linkwitz-Riley/Butterworth design. The order number here refers to filter circuits. It is not to be confused with crossover slope order number.

First Order Crossover Network
From left to right, the designs are for low-pass, high-pass, and band-pass crossover networks.

Second Order Crossover Network

Third Order Crossover Network

Fourth Order Crossover Networks

Source: CarStereo.com

The Cutoff Frequency Formula

The formula to calculate the cutoff frequency in low or high pass filters is

Fc = 1/(2*PI*R*C)

where

Fc = Cutoff Frequency
PI = 3.1416
R = Resistance in Ohms
C = Capacitance in Farads

and R*C is referred to as the time constant

Note that higher time constants shift the bandwidth lower, and high frequencies are attenuated more.
Lower time constants shift the bandwidth higher, and high frequencies are attenuated less. (The output is larger.) Actually, with lower time constants, the bandwidth is higher and more frequencies get through the circuit.

If you connect a capacitor in series with a speaker, the capacitor will act as a high pass filter. The higher the capacitance, the lower the cutoff frequency. The lower the capacitance, the higher the cutoff frequency.

A capacitor that is connected in parallel with a speaker will act as a low pass filter. The higher the capacitance, the lower the cutoff frequency. The lower the capacitance, the higher the cutoff frequency.

You should read these articles on 3 Way Crossover Example and Crossover Design. You can also use this Spreadsheet to calculate the capacitance and inductance needed for the design of a crossover network.

Designing Passive Crossovers

Tables 1 through 4 list component values for high- and low-pass filters at common cutoff frequencies and with slopes of 6, 12, and 18 dB per octave. (To find component values for other cutoff frequencies or higher slopes, consult The Loudspeaker Design Cookbook, published by Marshall Jones and marketed by Audio Amateur Publications [603-924-9464].

In our model, we'll start with the inductor and capacitor for the 4,000-Hz high-pass filter. Since we're dealing with a 4-ohm tweeter, refer to the intersection of the 4-ohm and 4,000-Hz columns in Table 2. In this case, the correct values for the high-pass filter are 6.8 pF for capacitor C2 and 0.22 mH for inductor L2.

The band-pass filter in this network consists of a 130-Hz high-pass filter and a 4,000-Hz low-pass filter. Referring again to Table 2, we find that the appropriate values for the high-pass side of the filter are 200 pF for capacitor C2 and 6.8 mH for inductor L2. For the low-pass side, the values are 6.8 pF for capacitor C2 and 0.22 mH for inductor L2.

For the 130-Hz low-pass filter, check the intersection of the 130-Hz and 4-ohm columns in Table 2. As you can see, you'll need a 200 pF capacitor for C2 and a 6.8 mH inductor for L2. It really is that easy, and building the more complicated networks shown in Figures 6 and 7 is simply a matter of adding a few more components to the picture.

Phase Shift
Timimg difference is used to express phase shift between two waves. In the following diagram, the blue and red waves are identical, but have a phase difference.

Source: Wikipedia

In addition to the effect of blocking frequencies, capacitors and inductors also waste power and energy that speakers could be using. Passive crossovers have another drawback. They introduce phase shifts, which put voltage and current out of phase with respect to each other. This affects the delivered power and the overall timing of the speaker.

A first-order (6dB/octave) croosover filter has a phase shift of 90 degrees.
A second-order(12dB/octave) crossover filter has a phase shift of 180 degrees.
A third-order (18dB/octave) crossover filter has a phase shift of 270 degrees.
A fourth-order (24dB/octave) crossover filter has no phase shift (zero degrees).

If you have a second-order crossover filter (180 degrees shift), you should wire the speaker out of phase. However, for the first and third-order crossovers filter, there is not an easy solution. For this reason, it is generally recommended that you try to stay with even-order crossovers filters.

A GUIDE TO SETTING CROSSOVER FREQUENCY FOR A SUBWOOFER

Setting the Low Pass Crossover Frequency
For additional information, read A Guide to Subwoofers and A Guide to Bass Management.

You need to set the crossover on the receiver’s menu and not the subwoofer. If your main front speakers are full-size with good bass response, set the low pass filter to 80Hz. If your main speakers are small, bookshelf, satellite, or in-wall, set the low pass filter in the 100 to 120Hz range. According to the Recording Academy recommendations, selecting a frequency between 80 and 100Hz will produce the best results.

Run the test tone generator for intervals between 30Hz to 200HZ and listen to the output level or measure it with an SPL meter. If different output levels are heard or read by the SPL meter for different frequencies, it is quite normal as different frequencies interact differently with the room acoustics. Increase or decrease the low-pass frequency to achieve the smoothest response. Decrease the crossover frequency if there is too much output around the crossover point, increase it if you notice a drop in the response.

In general, if the main speakers are large and capable of creating low frequency sound, it will be easier to match them with a subwoofer as opposed to the smaller speakers that most people own. However, it is not always best to set the crossover frequency at the lowest possible frequency to avoid the sonic signature of the subwoofer. If the crossover is set as low as possible, the subwoofer cannot stimulate the main speaker drivers near their resonance frequency, leaving only the main speakers as the dominant resonance contributor. If the crossover is set slightly higher, the bass from the subwoofer and the main speakers can reinforce one another resulting in a smoother and more pleasing bass.

You can download free test tone generators from the following sites:
RealTraps - Test Tone CD
Test Tone Generator Free Download
signal generator federal smoke at tasignal.com
Tone Generator Software - Create Audio Test Tones, Sweeps or Noise Waveforms

Advanced Crossover Settings in the Receiver’s Menu
Some higher-end receivers allow crossover settings for all the speakers, including surround speakers. It is important to remember that these settings are high-pass crossover settings. You should not confuse this with low-pass setting for the subwoofer.

The following table shows the power distribution at different crossover frequencies. The table came from a loudspeaker manual "Loudspeaker Enclosure Design and Construction", published by Fane as reported by Elliott Sound Products. According to this table, the equal power point is 350Hz.

250Hz: 40% (Bass), 60% (Mid+High)
350Hz: 50% (Bass), 50% (Mid+High)
500Hz: 60% (Bass), 40% (Mid+High)
1,200Hz: 65% (Bass), 35% (Mid+High)
3,000Hz: 85% (Bass), 15% (Mid+High)
5,000Hz: 90% (Bass), 10% (Mid+High)

Avoid an Audio Hole
A low-pass crossover frequency will block high frequency sound above the cutoff level. A high-pass crossover frequency will block frequencies below the cutoff level.

Typically, on many new recievers, the LPF ONLY affects the LFE channel (the ".1" channel), not the bass redirected from the other 5 or 7 channels. That is why you normally set it to 120Hz to make sure you receive all the information that the producers intended to put in the LFE channel. However, if the implemented LPF in the receiver affects the redirected bass from the other SMALL speakers, do not adjust the low-pass frequency too far below the high-pass frequency. The previous statement also applies to adjusting the crossover dial on the back of the subwoofer. You could end up with an audio hole in between the low-pass and high-pass frequencies.

However, remember that crossover networks cut frequencies progressively. As a result, if, for example, the high-pass frequency for the small speakers is set at 100Hz, and you set the low pass frequency around 80Hz or 90Hz, you will most likely be ok. If, however, you set the low-pass frequency around 60Hz to 70Hz, then you would most likely end up with an audio hole. Can you really hear the difference? I will leave the decision up to you.

THX Recommendation
Although the 80 Hz crossover is a good starting point for many speakers, you have to realize that the THX recommendation started in the late 1980's with Dolby Pro Logic and later with Dolby Digital and applies to THX certified speakers. These speakers are required to have 80 Hz crossover to a THX certified subwoofer. It is not a blind recommendation that applies to all speakers.

There is additional information on the implication of different filter slopes on crossover settings in A Guide to Bass Management (Part II).

WHERE TO BUY CROSSOVER NETWORKS AND COMPONENTS

Fmod and Subsonic Filters: http://store.hlabs.com/
http://www.madisoundspeakerstore.com...ers-and-parts/
CROSSOVER NETWORKS from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.
Subwoofer Crossover: SUBWOOFER CROSSOVER from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.
Two-Way Crossover: 2-WAY CROSSOVERS from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.
Three-Way Crossover: 3-WAY CROSSOVERS from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.
Marchand Electronics, high quality audio components, electronic crossovers, active and passive, PLLXO
Solen Electronique Inc.
External Active Crossover: http://www.amazon.com/s/ref=nb_ss_gw...ssover+network
http://www.amazon.com/s/ref=nb_ss_gw...work&x=14&y=25
eBay Store – AudioBlowouts: Search results for.
3-Way Active Stereo Crossover Network
Gemini Electronic Components

Passive Crossovers, Capacitor & Coil Calculator:
Passive Crossovers, Capacitor and Coil Calculator
http://www.carstereo.com/help/Articl...ume+Calculator
http://www.erseaudio.com/CrossoverCa...nd-Order-3-Way
http://www.bcae1.com/xoorder.htm
http://www.pvconsultants.com/audio/targetgen/pcdc.htm
http://www.ajdesigner.com/
http://www.ajdesigner.com/crossover/crossoverfirst.php
http://radiosvalka.narod.ru/soft/soft_e.htm

Combining Capacitors and Inductors to Get the Derired Values:
http://www.diyaudioandvideo.com/Electronics/Basic/

ADDITIONAL INFORMATION AND REFERENCES

Two Way Crossover Basics, what IS a crossover?
Band-pass filters : FILTERS
Parts Express - Capacitors And Inductors
COROLLARY THEOREMS - ELECTRONINC DESIGN NOTES: Analog Filters
Understanding Audio Crossovers | Onstage Article Explains Science Behind Crossovers for P.A.s
Low-pass filter - Wikipedia, the free encyclopedia
High-pass filter - Wikipedia, the free encyclopedia
Band-pass filter - Wikipedia, the free encyclopedia
Passive Crossover Networks
http://www.thespeakercompany.com/Wha...sover-W10.aspx
Crossovers
Car Audio Help Guide
Inductor - Wikipedia, the free encyclopedia
Capacitor - Wikipedia, the free encyclopedia
Resistor - Wikipedia, the free encyclopedia
RL circuit - Wikipedia, the free encyclopedia
Audio crossover - Wikipedia, the free encyclopedia
http://www.audioholics.com/education...r-loudspeakers
A Guide to Subwoofers: Characteristics, Placement, & Adjustments - Blu-ray Forum
RealTraps - Test Tone CD
Test Tone Generator Free Download
signal generator federal smoke at tasignal.com
Tone Generator Software - Create Audio Test Tones, Sweeps or Noise Waveforms
Calibrating Your Audio With an SPL Meter - Blu-ray Forum
LoudspeakerBuilder.ca - (Speaker Crossover Networks)
Passive Crossover Network Design
audioinfo4u.com / Renewal Website
Google Image Result for http://www.troelsgravesen.dk/T14_files/1S_OWI_crossover.gif
http://www.termpro.com/articles/xover.html
http://www.snippets.org/filters/crossover.htm

[Driver_King]

Very thorough thread you've got there. It makes me want to build some DIY speakers like these. Maybe later on next year. I have an old Technics amp that I'm interested in using again too. Thanks for the article. I've been wanting to upgrade the crossover components in my SDA's so this will also help.

[Big Daddy]

Originally Posted by Driver_King

Very thorough thread you've got there. It makes me want to build some DIY speakers like these. Maybe later on next year. I have an old Technics amp that I'm interested in using again too. Thanks for the article. I've been wanting to upgrade the crossover components in my SDA's so this will also help.

Take a look at my Subwoofer Repairs thread. I left a message for JJ about a beautiful speaker that he should design. There is a link for the entire plan.

Are you interested in the 15" driver I removed out of the old subwoofer? It still works. No charge. Only shipping. Surprisingly, it is not very heavy.

[mdabb]

"solen.ca" is one of the best places for x-over's, parts and speakers. Hands down one of the best !!!

[Big Daddy]

Originally Posted by mdabb

"solen.ca" is one of the best places for x-over's, parts and speakers. Hands down one of the best !!!

Something is wrong with their web site. I can't get there.

[mdabb]

Originally Posted by Big Daddy

Something is wrong with their web site. I can't get there.

It will be back up sooner or later, this company is not going anywhere. Many "high-end" speaker manufacturers use Solen.

[JasonR]

Very informative thread!!! I am still toying with the idea of building my own, it will be after the holidays at the earliest though....

[Big Daddy]

Originally Posted by JasonR

Very informative thread!!! I am still toying with the idea of building my own, it will be after the holidays at the earliest though....

A few people are actually thinking about building one during the holidays. JJ is one of them. I already have 5 subwoofers plus the two 15" ones that are built inside the Def Tech super Towers. If I buy or build another subwoofer, I will get arrested.

[Driver_King]

Originally Posted by Big Daddy

Take a look at my Subwoofer Repairs thread. I left a message for JJ about a beautiful speaker that he should design. There is a link for the entire plan.

Are you interested in the 15" driver I removed out of the old subwoofer? It still works. No charge. Only shipping. Surprisingly, it is not very heavy.

That's a little beyond me there for that price. It is gorgeous though. That design I linked you to earlier is a single driver speaker pair. It is inexpensive to make and seems like a good idea, especially according to their raving review of it. I'll PM you about the driver.

[Go Blue]

Can someone confirm if I have this right? Low pass (set by sub itself) and high pass (set by receiver) do not have to be the same frequency. I can set the high pass in the receiver's menu to say 100hz and have the low pass dial on the back of my sub set to "Direct" (200hz). Am I off on this?

[aramis109]

Originally Posted by schultz

Can someone confirm if I have this right? Low pass (set by sub itself) and high pass (set by receiver) do not have to be the same frequency. I can set the high pass in the receiver's menu to say 100hz and have the low pass dial on the back of my sub set to "Direct" (200hz). Am I off on this?

Nah, that's fine. You have your LPF dictated by the receiver instead of the subwoofer. Basically the receiver will only give the sub 100hz and below, and because the sub is set at 200hz, it'll take everything the receiver gives it.

[Go Blue]

Originally Posted by aramis109

Nah, that's fine. You have your LPF dictated by the receiver instead of the subwoofer. Basically the receiver will only give the sub 100hz and below, and because the sub is set at 200hz, it'll take everything the receiver gives it.

I know that will work, but is that a good way to go about it?

[Big Daddy]

Originally Posted by schultz

I know that will work, but is that a good way to go about it?

You are ok with your setup.

The crossover on the back of your subwoofer is low pass and has become obsolete with modern receivers and in home theater apllications. That is the reason you always leave it wide open (highest point) and let the receiver control your low pass frequency.

In music applications, if you are using an old-style preamp and amplifier, then you need to control your low pass frequency on the back of the subwoofer.

[ldrover]

I currently have a Pioneer 5.1 HTIB. I am about to purchase two PSB Alpha T1's and a C1. I plan to keep the two small pioneer surrounds. From what I have read, the Alpha's are probably best set to crossover to the sub at 80-100 Hz. The pioneer surrounds I am using are set at 140 Hz. Will this be OK or do all the speakers need to be set to crossover at the same point?

[Big Daddy]

Originally Posted by ldrover

I currently have a Pioneer 5.1 HTIB. I am about to purchase two PSB Alpha T1's and a C1. I plan to keep the two small pioneer surrounds. From what I have read, the Alpha's are probably best set to crossover to the sub at 80-100 Hz. The pioneer surrounds I am using are set at 140 Hz. Will this be OK or do all the speakers need to be set to crossover at the same point?

All speakers do not need to have the same crossover setting. It all depends on the frequency performance of the speaker.

While 80 Hz on the PSBs will work, the 140 Hz on the Pioneers will make your bass sound a bit directional. As long as the Pioneers can go that low, I would suggest that you try a range of crossover frequencies like 100 Hz, 120 Hz, and 140Hz and see which one sounds best.

[jshannon]

That's a lot of information. I think I got a lot of it, but not everything. How would you set up this SW? I'm not sure about the phase or in/out. From what I understand, the low-pass filter should be all the way down, and the settings should be done on the receiver. I assume the volume would be set at whatever sounds good.

[Big Daddy]

Originally Posted by jshannon

That's a lot of information. I think I got a lot of it, but not everything. How would you set up this SW? I'm not sure about the phase or in/out. From what I understand, the low-pass filter should be all the way down, and the settings should be done on the receiver. I assume the volume would be set at whatever sounds good.

Volume Setting:
Around 50% is good. You can adjust it a little to make sure your bass response is smooth and matches the level of your other speakers. However, do not go beyond the 3/4 point. You don't want to kill your subwoofer.

Crossover Stting:

• Turn the low pass filter knob all the way to the right (clockwise) to 180Hz.
• In the receiver's menu, set the low pass filter to 80Hz.
• If your receiver allows setting the crossover frequency of the individual speakers, adjust them accordingly. For example, if you have very small surround speakers, set their crossover to 100Hz. Immediately, go back and set the low fass filter in Step 1 to 100Hz.

Phase Setting:
When the woofer on the sub and the woofers of the front speakers move in and out in sync with each other, the system is said to be in phase. When the speakers and the subwoofer are moving out of sync with each other, the subwoofer and the front speakers’ bass overlap and cancel each other. In this case the system is said to be out of phase, resulting in less bass.

Unfortunately, there may be another problem between the main speakers and the subwoofer. If the main speakers are producing bass at the same time as the subwoofer, at some points the bass will reinforce each other. At other points the bass will cancel each other. The solution is to allow only the subwoofer to reproduce bass by setting the front speakers to small in the receiver’s setup menu. This can yield a smoother bass response throughout the entire room.

To get the best bass response, you should set the phase (polarity) of the subwoofer(s) to deliver the highest output at the listening position. This can be achieved with the help of a test signal at the crossover frequency and an SPL meter. You should run this test several times by changing the polarity of the subwoofer and measuring the bass response on the SPL meter. Select the phase option that results in the highest bass response. If you don’t have an SPL meter, you will have to trust your ears.

When setting the subwoofer phase by ear, play some music (not a movie) that has a repetitive bass line. Switch the polarity several times and choose whichever setting sounds better. If you do not hear any difference, leave the phase switch at “0" or “normal”.

[zicmubleu]

Big Daddy - I just read through this section again, didn't think to check the subwoofer section for bi-amping configuration. I ordered some Pyle Pro three way active crossovers and will eventually use them to bi-amp my speakers, but I had planned on letting the AVR do the sub-woofer crossover portion. Now I see that my active crossovers will likely do a 180 phase shift which I am assuming will make the final bi-amp signals out of phase with the existing sub-woofer signal. Obviously I will have to get an SPL meter and run the phase tests you mentioned, but I am wondering if I have a correct understanding of this aspect. I am assuming that the AVR filters out the low frequencies from the pre-out jacks, and didn't plan on using the active crossover to generate the sub-woofer channel. Thanks for your help.

[Big Daddy]

Originally Posted by zicmubleu

Big Daddy - I just read through this section again, didn't think to check the subwoofer section for bi-amping configuration. I ordered some Pyle Pro three way active crossovers and will eventually use them to bi-amp my speakers, but I had planned on letting the AVR do the sub-woofer crossover portion. Now I see that my active crossovers will likely do a 180 phase shift which I am assuming will make the final bi-amp signals out of phase with the existing sub-woofer signal. Obviously I will have to get an SPL meter and run the phase tests you mentioned, but I am wondering if I have a correct understanding of this aspect. I am assuming that the AVR filters out the low frequencies from the pre-out jacks, and didn't plan on using the active crossover to generate the sub-woofer channel. Thanks for your help.

Are you trying to de-activate the passive crossovers inside your speakers?
If the answer is yes, make sure you get the information about the current crossover frequencies at which the midrange drivers take over from the woofer and the tweeters take over from the midrange drivers.
The phase cancellation between the front speakers and an external subwoofer are partially taken care off by the low pass filter (normally 80Hz) inside the receiver. By setting the front speakers to small and crossing out the low frequencies, you are effectively sending all these signals to the subwoofer.

[zicmubleu]

Originally Posted by Big Daddy

Are you trying to de-activate the passive crossovers inside your speakers?
If the answer is yes, make sure you get the information about the current crossover frequencies at which the midrange drivers take over from the woofer and the tweeters take over from the midrange drivers.
The phase cancellation between the front speakers and an external subwoofer are partially taken care off by the low pass filter (normally 80Hz) inside the receiver. By setting the front speakers to small and crossing out the low frequencies, you are effectively sending all these signals to the subwoofer.

My drivers are just the cones, magnets and frames, assembled of course, in shipping boxes at the moment, waiting to be installed in cabinets, a DIY project. So there is no existing crossover with them to bypass, etc. I just ordered three Pyle active crossovers that you mentioned in the separates thread. I plan to use my AVR, Sony STRDG1000 as a pre/pro to feed into the Pyle active crossovers and the AVR's subwoofer output for the sub-woofers, currently they exist as Acoustic Audio HD-10, also a tip from you. Since the AVR apparently does it's filter/crossover for the sub using DSPs instead of conventional crossover circuitry I am assuming that they probably don't phase shift their output. The Pyle active crossovers will phase shift their outputs 180 degrees which will obviously be different than the original method used to the AVR amplifier stage. The output of the Pyle crossovers will feed to dual NAD amps if all goes as planned, also a tip from you. So my general question is, is that rationale correct? Just checking to see if I understood your posting on crossovers correctly.

Since my speakers "don't exist" per-se, the actually crossover frequency I will use for those speakers will be determined by trial and error. Probably I should have posted my question in the separates thread but the subwoofer thread also applies with the phase shifting. Life would be easier if the pre-pro offered DSP crossover outputs for two and three way systems, but even if they did they would most likely be out of my price range.

Thanks for all the great advice. Steve