Crossover Frequency

[guggas]

I have an older Outlaw LFM-2 Sub and these EMP Tek E5Ti Tower Speakers towers.

What should i set my crossover frequency to in my reciever?

thanks

 

[sholling]

I generally like to set the crossover a minimum of 10hz higher than the lower rated limit of the speakers. In your case the speakers are rated to 50hz so I'd play around with crossover setting between 60 and 80hz and see how it sounds to you. That's because a crossover isn't a sharp cutoff, the crossover is a gradual slope starting well below the setting and finishing well above.

 

[Josuah]

I generally like to set the crossover a minimum of 10hz higher than the lower rated limit of the speakers. In your case the speakers are rated to 50hz so I'd play around with crossover setting between 60 and 80hz and see how it sounds to you. That's because a crossover isn't a sharp cutoff, the crossover is a gradual slope starting well below the setting and finishing well above.

Crossovers are in terms of octaves, so it's probably better to think of it that way instead of a fixed 10Hz. I'd go with 80Hz if the speaker specifications are 50Hz. Especially considering it is 50Hz at +/-3dB, which means it could be -6dB down at 50Hz.

Best option is to measure and set the crossover that way. Taking into account that at higher volumes, a higher crossover may be necessary than what works at lower volumes.

 

[sholling]

Crossovers are in terms of octaves, so it's probably better to think of it that way instead of a fixed 10Hz. I'd go with 80Hz if the speaker specifications are 50Hz. Especially considering it is 50Hz at +/-3dB, which means it could be -6dB down at 50Hz.

Best option is to measure and set the crossover that way. Taking into account that at higher volumes, a higher crossover may be necessary than what works at lower volumes.

Yes crossovers work in octaves but very few people think in octaves or could tell you what that one octave above 50hz translates to in hertz. There are exceptions but this is the beginner and audiophyte area. If it were my setup I'd probably start with 70hz and see how it sounds (adjusting up to 80hz if necessary) but not every receiver will crossover at 70 making 80hz a good solid recommendation.

 

[Impelled]

Dont forget to set the subs crossover to allow full frequency.
This is so it doesnt add to the effect of the amps crossover.

 

[guggas]

Thanks for the input guys, when i first decided i wanted to upgrade my audio experience i never realize how many little things there are you need to know.

Dont forget to set the subs crossover to allow full frequency.
This is so it doesnt add to the effect of the amps crossover.

I assume your talking about the in/out toggle switch on the back of the sub that disables the subs crossover? If thats the case yeah i got that covered.

My towers should be delivered tomorrow, im pretty stoked.

 

[ParadigmDawg]

Man, I have played around with crossover points until I'm blue in the face and I always end up back at 80hz. May mains dig pretty deep but 80 just seems to be the best blend of everything. (My surround are crossed over at 120hz).

My mains:
Low-Frequency Extension 25 Hz (DIN)* DIN 45 500. Indicates -3 dB in a typical listening room.

Frequency Response:
On-Axis
30° Off-Axis
±2 dB from 44 Hz - 22 kHz
±2 dB from 44 Hz - 20 kHz

 

[DD66000]

Crossovers are in terms of octaves, so it's probably better to think of it that way instead of a fixed 10Hz. I'd go with 80Hz if the speaker specifications are 50Hz. Especially considering it is 50Hz at +/-3dB, which means it could be -6dB down at 50Hz.

If its +/- 3db that is what it means. Those speaker will not be -6db @ 50 htz. They will be -3db @ 50 htz.
As for octaves, from any given frequency, in this case 50 htz; one octave higher is double (100 htz), and one octave lower is half (25 htz).
So if the roll off slope is 6db then the speaker would be -9db @ 25 htz.
If the slope was 12db, then the speaker is -15db @ 25 htz.

I do have sats that are -6db @ 80 htz, as they are designed as such for when they are connected/stacked to their matching subs and the internal XO is used @ 130 htz. But when wall mounted, in the case of surrounds, they gain back 3db. So they end up being -3db @ 80 htz.

 

[Josuah]

If its +/- 3db that is what it means. Those speaker will not be -6db @ 50 htz. They will be -3db @ 50 htz

+/-3dB is used to indicate a window between the frequency points listed. In which case the mid-range may be +3dB (near the top of the window) while the 50Hz point would be -3dB (near the bottom of the window) but from a listening perspective that means they will be -6dB because the "flattest" curve would be achieved when you set your crossover to match the mid-range.

If there were only a few small peaks at +3dB then sure, the 50Hz point would be -3dB. But that's not how the +/-3dB specification is used. For example, the Axiom Audio M22 v3 speakers are listed as 60Hz - 20kHz +/-3dB. Looking at the actual frequency response plot, the SPL is ~86dB @ 60Hz. The overall SPL throughout the remainder of the frequency is ~92/93dB. So I would consider them -6dB @ 60Hz. The right crossover might be around 100Hz.

I do have sats that are -6db @ 80 htz, as they are designed as such for when they are connected/stacked to their matching subs and the internal XO is used @ 130 htz. But when wall mounted, in the case of surrounds, they gain back 3db. So they end up being -3db @ 80 htz.

Perhaps they are -6dB down at 80Hz because they are for THX setups? I think that was the requirement.

 

[DD66000]

+/-3dB is used to indicate a window between the frequency points listed. In which case the mid-range may be +3dB (near the top of the window) while the 50Hz point would be -3dB (near the bottom of the window) but from a listening perspective that means they will be -6dB because the "flattest" curve would be achieved when you set your crossover to match the mid-range.

If there were only a few small peaks at +3dB then sure, the 50Hz point would be -3dB. But that's not how the +/-3dB specification is used. For example, the Axiom Audio M22 v3 speakers are listed as 60Hz - 20kHz +/-3dB. Looking at the actual frequency response plot, the SPL is ~86dB @ 60Hz. The overall SPL throughout the remainder of the frequency is ~92/93dB. So I would consider them -6dB @ 60Hz. The right crossover might be around 100Hz.



Perhaps they are -6dB down at 80Hz because they are for THX setups? I think that was the requirement.

Its not the way I see it. Its +3db above zero and -3db below. so its still -3db at 50 htz.

And the -6db for the PT800 has nothing to do with THX. It has to do with the internal XO of 130 htz when the PT800 is docked to the PS1400 sub. Creating a full range speaker.

 

[Impelled]

Speakers are usually rated in open air.
If you place it near a wall it will gain up to 3dB.

 

[DD66000]

Speakers are usually rated in open air.
If you place it near a wall it will gain up to 3dB.

Which is what I said in post #8. In the case of my PT800s they go from -6db to -3db when wall mounted.

 

[Impelled]

It is yes

 

[Josuah]

Its not the way I see it. Its +3db above zero and -3db below. so its still -3db at 50 htz.

Okay, there's nothing wrong with saying it that way. But does that mean you would set your subwoofer level (measured flat for the purpose of argument) at the zero point? If so, your subwoofer will be on average -3dB lower than your mains. Or would you set your subwoofer so it is +3dB? And so when measuring, it is flat at +3dB? Except I'd want to set my crossover at a frequency so that when integrated everything was flat at +3dB, which will be some point higher than 50Hz then?

 

[Impelled]

Depends where you place your subwoofer.
If its near a single wall, you will gain up to 3dB, near a corner will gain up to 6dB.

 

[guggas]

I got my speakers in today, and set them up. I did the auto calibrate function and then went in to manually set crossover. It turns out my only chooces are 50, 80, 100, 150, and 200.
It sounds the best at 80.

 

[DD66000]

Okay, there's nothing wrong with saying it that way. But does that mean you would set your subwoofer level (measured flat for the purpose of argument) at the zero point? If so, your subwoofer will be on average -3dB lower than your mains. Or would you set your subwoofer so it is +3dB? And so when measuring, it is flat at +3dB? Except I'd want to set my crossover at a frequency so that when integrated everything was flat at +3dB, which will be some point higher than 50Hz then?

At ANY XO point when both drivers are -3db they sum together to produce a flat response @ zero.
When I play my older L212s which have a acoustical roll off @ 70 htz I set my P7 pre-amp @ 80 htz for the sub XO, being my choices are 50, 80, off.

For my PT800s, I set the sub's XO to 100~110, which is about the max for the SUB1500, as it is VLF sub. So that gets me close to the PT800's -3db point. If I were to set the sub XO to 80 then I would end up with a 3db dip, as the PT800 is -6db @ 80.
So that gets me close to what the PT800 was designed for, when stacked to a PS1400 sub to make a full range system with the XO @ 130.

 

[Irvrobinson]

Man, I have played around with crossover points until I'm blue in the face and I always end up back at 80hz. May mains dig pretty deep but 80 just seems to be the best blend of everything. (My surround are crossed over at 120hz).

I played around similarly and came to the same conclusion, a high-pass filter at 80Hz for the mains. Since we have a different speakers, subs, and rooms, I wonder why 80Hz is turning out to be some sort of magic crossover frequency?

 

[DD66000]

I played around similarly and came to the same conclusion, a high-pass filter at 80Hz for the mains. Since we have a different speakers, subs, and rooms, I wonder why 80Hz is turning out to be some sort of magic crossover frequency?

80 htz is the point where the bass becomes omni directional. Meaning anything below that point the direction of the sound can not be located. And even with 'full range' speakers, unless driven by a very large amp, will not be as forceful as a good sub.
If you have the good fortune to have something like the Revel Salon2 and have very good amps, like a pair of Parasound JC1 mono blocks, then those full range speakers will kick ***.

The one exception in most cases for the XO point is if the mains and sub(s) are co-located. Such as with a JBL Performance Series system. When docked together and the internal 130 htz XO is used, they become a full range system with a built-in powered sub. So the 130 htz XO does not become a problem as both share the same location.