I have a 5.1 set up. Ascend Acoustics 340SE L/C/R, Ascend Acoustics 200SE RS/LS and an Epik Phoenix subwoofer. My subwoofer is up front between the CC and RF speakers. I sit about 14 feet away.
I run all speakers "small" and have tried an 80hz and 100hz crossover, but have yet settled on one. Neither one causes localization of the bass that I can tell.
I have read somewhere that if you have a good articulate subwoofer, you should run as high of a crossover as you can, just short of any localization.
Is this true?
What would be the advantages and disadvantages?

I have a 5.1 set up. Ascend Acoustics 340SE L/C/R, Ascend Acoustics 200SE RS/LS and an Epik Phoenix subwoofer. My subwoofer is up front between the CC and RF speakers. I sit about 14 feet away.
I run all speakers "small" and have tried an 80hz and 100hz crossover, but have yet settled on one. Neither one causes localization of the bass that I can tell.
I have read somewhere that if you have a good articulate subwoofer, you should run as high of a crossover as you can, just short of any localization.
Is this true?
What would be the advantages and disadvantages?

100 Hz is still considered mid-bass. Typically a subwoofer can provide more headroom than monitor type speakers.

Instead of focusing on localization you are probably going to have to play some movies with a lot of bass at a very high level, maybe as high as 105-110 db. Do it with both crossover frequencies and see if you hear any difference.

Caveat: You might want to check with Ascend to make sure that your Ascend speakers can handle material with substantial upper bass at levels as high as 110 db.

The bottom line is that some monitor speakers simply can't handle bass in the 100-200 Hz range as well as a subwoofer.

That's why people who buy really powerful subwoofers sometimes have mains and other speakers that simply can't keep up with their subwoofer.

Thanks for the reply Spyboy,
I think the 340SE's can handle 100hz quite well
http://www.ascendacoustics.com/pages/products/speakers/cmt340m/cmt340mmeas.html
That said, I would bet the 18" driver on the Phoenix might be able to handle 100hz material a bit better though

I would imagine that the Ascends can also reproduce bass down to just below 50 Hz (probably not at very high levels to be sure but there is some form of usable output there).

I would choose an 80 Hz crossover. You give up a little headroom but that headroom might only be a problem if you're watching at very high listening levels. Book shelf speakers like the Ascend 340's should be more than capable of playing loud down to 70 Hz.

Perhaps not 105 dB's loud but rarely do people listen that loud in the first place. If you choose a 100 Hz crossover, then you'll have slightly less distortion at higher listening levels but greater chance of sub localization (24 dB's per octave/4th-order slope on the low pass means that output will roll off at 24 db's between 100-200 Hz).

Sub localization is generally considered to occur from 120 Hz and upwards. At 100 Hz, although the low pass filter is steep, it might not be steep enough to mitigate the higher frequencies from 'leaking through', as it were.

In my opinion, I would try to minimize any possible localization. This is just what I would do but I also would measure the response to see if a lower crossover point gives a smoother splice between speaker and subwoofer.

As always, experimentation is key.

Regards,

I would imagine that the Ascends can also reproduce bass down to just below 50 Hz (probably not at very high levels to be sure but there is some form of usable output there).

I would choose an 80 Hz crossover. You give up a little headroom but that headroom might only be a problem if you're watching at very high listening levels. Book shelf speakers like the Ascend 340's should be more than capable of playing loud down to 70 Hz.

Perhaps not 105 dB's loud but rarely do people listen that loud in the first place. If you choose a 100 Hz crossover, then you'll have slightly less distortion at higher listening levels but greater chance of sub localization (24 dB's per octave/4th-order slope on the low pass means that output will roll off at 24 db's between 100-200 Hz).

Sub localization is generally considered to occur from 120 Hz and upwards. At 100 Hz, although the low pass filter is steep, it might not be steep enough to mitigate the higher frequencies from 'leaking through', as it were.

In my opinion, I would try to minimize any possible localization. This is just what I would do but I also would measure the response to see if a lower crossover point gives a smoother splice between speaker and subwoofer.

As always, experimentation is key.

Regards,


Thanks I will continue to play around with both a bit more. I think either will work in my situation

The Ascends could do 60hz at lower volumes and 80hz with no problem. It all depends on how loud you listem and how safe you want to be.I'd stick with 80hz.

Sub localization is generally considered to occur from 120 Hz and upwards. At 100 Hz, although the low pass filter is steep, it might not be steep enough to mitigate the higher frequencies from 'leaking through', as it were.


Gene, have you ever done some frequency tests....really 60 or 70Hz seems localized but maybe that depends on the dimensions of the room.

To the OP, I would figure out what plays those frequencies better, measurements are needed. If the sub does better up to say 90Hz then crossover there, if the mains do better then crossover where they stop performing better then the sub. There is no hard set crossover value, it takes measurements to really know for sure.

or let Audyssey/AVR do it all for you (If you have it).

Gene, have you ever done some frequency tests....really 60 or 70Hz seems localized but maybe that depends on the dimensions of the room.



it will also depend on where the sub is located in the room. if it's up front and center then i doubt you'd be able to localize it crossed at 80hz, maybe even 100hz.

it will also depend on where the sub is located in the room. if it's up front and center then i doubt you'd be able to localize it crossed at 80hz, maybe even 100hz.

Good point! if its near your mains then there could be an advantage of running it to 120Hz. I know there isnt many many speakers that have the slam a good sub can give us.

I am using Anti-Mode 8033 for the sub and MCACC on my Elite SC-05 for the speakers.
I believe the 8033's correction range is 16hz to 144hz. I will guess that the Epik will probably do 100hz better than the Ascends.
Although, if I set the XO to 100hz, what frequencies over 100hz will the subwoofer still play?

I am using Anti-Mode 8033 for the sub and MCACC on my Elite SC-05 for the speakers.
I believe the 8033's correction range is 16hz to 144hz. I will guess that the Epik will probably do 100hz better than the Ascends.
Although, if I set the XO to 100hz, what frequencies over 100hz will the subwoofer still play?

Providing it's a 24db per octave slope on the SC-05 for the sub, which I think it is, someone can correct me if I'm wrong.

If you set the XO to 100hz it will be -24db down at 200hz. A 120hz setting will be down -24db at 240hz.