• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Newbie Subwoofer Questions

NoSnakeOil2

Member
Joined
May 15, 2020
Messages
68
Likes
75
Hi, everyone. I have a couple of questions on working with subwoofers.

1) Is it possible to adjust a subwoofer's volume without constantly manually turning the knob on the subwoofer itself? Can this be done by using the high level binding posts on the sub? In what order would i hook up the speaker and the sub? I know SVS has an app to do this, but I wanted to know if there is a different way.

2) How can one hook up 2 subs with just 1 amp?

3) How can one make sure lower signals, e.g., below 80 hz, go only to the sub and not to the speakers? I rarely see amps that have high pass or low pass filters (if those are the proper terms)

Thanks in advance to everyone for their knowledge.
 

Chrispy

Major Contributor
Forum Donor
Joined
Feb 7, 2020
Messages
4,274
Likes
3,222
Location
PNW
Depends on what your "amp" is capable of as well as the specific sub(s). If you have a remote app for the sub, or for the "amp" that's one way to control level. Preferably if you want to implement a crossover or high pass for the speakers it's part of your "amp" or in a separate unit, most subs do not provide such. So what specific gear do you have or want to use?
 
OP
NoSnakeOil2

NoSnakeOil2

Member
Joined
May 15, 2020
Messages
68
Likes
75
Depends on what your "amp" is capable of as well as the specific sub(s). If you have a remote app for the sub, or for the "amp" that's one way to control level. Preferably if you want to implement a crossover or high pass for the speakers it's part of your "amp" or in a separate unit, most subs do not provide such. So what specific gear do you have or want to use?
My current sub just has the connection that goes to the "sub out" on my integrated amp or pre-amp. I guess I could get a SVS sub that has volume software, but I wondered if using the high level posts could provide a cheaper or more elegant solution.
 

Chrispy

Major Contributor
Forum Donor
Joined
Feb 7, 2020
Messages
4,274
Likes
3,222
Location
PNW
My current sub just has the connection that goes to the "sub out" on my integrated amp or pre-amp. I guess I could get a SVS sub that has volume software, but I wondered if using the high level posts could provide a cheaper or more elegant solution.
If you use the high level/speaker level inputs your volume is simply tied to that of your L/R speakers as well as an overlap of frequencies. If you have typical 2ch gear your pre-amp/integrated are of little help except to provide same volume control via the pre-out (which also tends to be full range, altho some gear offers more....why I asked what you are using).
 
OP
NoSnakeOil2

NoSnakeOil2

Member
Joined
May 15, 2020
Messages
68
Likes
75
If you use the high level/speaker level inputs your volume is simply tied to that of your L/R speakers as well as an overlap of frequencies. If you have typical 2ch gear your pre-amp/integrated are of little help except to provide same volume control via the pre-out (which also tends to be full range, altho some gear offers more....why I asked what you are using).
Thanks! That's what i thought.)))) I'll probably have more silly questions in the future. )))
 

Head_Unit

Addicted to Fun and Learning
Forum Donor
Joined
Aug 27, 2018
Messages
916
Likes
444
I rarely see amps that have high pass or low pass filters (if those are the proper terms)
Yeah it's a big and stupid problem, at least for 2-channel products, which worse sometimes have a "subwoofer" output but no highpass filtering to remove the bass load from the main amp and speakers. And speaker level connections don't work for that.
- The easiest solution is to get an audio-video receiver (AVR) which all have bass management. Then for somewhat more $$ you can get a good room correction like Audyssey XT32 (with App control from Denon or Marantz) or Dirac or ARC. This can help flatten your bass response a lot.
- Otherwise Parasound, Outlaw, maybe some NAD models have highpass. Some few Yamahao through their YPAO room EQ; their literature and specs are not too clear about highpass filtering.
- Audyssey Sub EQ HT independently equalizes two subs (you have to dig into spec sheets to see if a model has this). ARC I believe can also EQ two subs, also Dirac, but I don't know what name they use for that feature.
- Otherwise you can connect two subs to one RCA output with a "male to 2 rca female" Y-cable. However you may not get great response depending on positioning.
- The SVS App is really handy to adjust sub level on the fly. Someone had posted most AVRs have a function on their remote to do this.
 

anotherhobby

Active Member
Forum Donor
Joined
Dec 17, 2021
Messages
258
Likes
499
Hi, everyone. I have a couple of questions on working with subwoofers.

1) Is it possible to adjust a subwoofer's volume without constantly manually turning the knob on the subwoofer itself? Can this be done by using the high level binding posts on the sub? In what order would i hook up the speaker and the sub? I know SVS has an app to do this, but I wanted to know if there is a different way.
You will want to configure your system in a such a way that the subwoofer volume goes up and down with the main volume. Once they are level matched with your mains, if some songs/tones make you want to adjust the subwoofer volume after that, it's because you have room modes (excited frequencies). If your system is EQ'd to flatten out the room modes and provide a smooth frequency response, you shouldn't generally have the desire to adjust the volume of the sub independently. It should sound correct all the time.

2) How can one hook up 2 subs with just 1 amp?
On one system I did it by using a miniDSP Flex as my pre-amp/DAC/crossover/DSP device. It has 4 outputs, so two go to the amp for R/L mains and two go to the subs as mono. It also does Dirac room correction. It fixed all my room modes perfectly and the software is pretty straight forward. It also acts as a crossover and has 80 Hz 24dB/oct hi/low pass filters for the mains and subs.

On my other system I have a Denon AVR with 2 subs. I run a miniDSP 2x4 between the Denon and the subs. The miniDSP runs a bunch of EQ for each sub that was generated by Multi-Sub Optimizer. The Denon only see's 1 sub, but it's two subs that are already integrated and DSP corrected for the room. On top of that the Denon runs Audyssey room correction and puts an 80 Hz high pass on the main speakers and the same low pass to the subs.

3) How can one make sure lower signals, e.g., below 80 hz, go only to the sub and not to the speakers? I rarely see amps that have high pass or low pass filters (if those are the proper terms)
You need to insert a crossover between the source/pre-amp and the amp. Then the crossover will split the signal to the amp and the subs. That is the correct way to do it, but if you have an integrated amp, that might mean getting something like the miniDSP Flex as a pre-amp/DSP/crossover and then just using your integrated amp as an amp. If you want to use the inputs on your integrated amp, then you can't do a high pass fiter on the mains. Your best option then is to figure out where your main's roll off, and try to adjust the sub's low pass filter to match as best as possible.
 

posvibes

Active Member
Forum Donor
Joined
Jul 4, 2020
Messages
181
Likes
242
This may be the silliest question ever asked about a subwoofer, but here goes: can the depth to the frequency of an active subwoofer puts out be set/limited or is that a matter of how the gain is set? For example if used with a set of bookshelf speakers and the crossover set to 80Hz and the subwoofer is capable of 27Hz at whatever -dB, can it be set to say 36 Hz?
 

Chrispy

Major Contributor
Forum Donor
Joined
Feb 7, 2020
Messages
4,274
Likes
3,222
Location
PNW
This may be the silliest question ever asked about a subwoofer, but here goes: can the depth to the frequency of an active subwoofer puts out be set/limited or is that a matter of how the gain is set? For example if used with a set of bookshelf speakers and the crossover set to 80Hz and the subwoofer is capable of 27Hz at whatever -dB, can it be set to say 36 Hz?
Not generally, although with appropriate dsp (not usually present on the sub itself) you could do that, but why would you want to limit the sub's response? Some subs have various eq settings in combination with open/closed ports that can affect the f3 (which assume is what you're talking about with the 27hz or 36hz mentions). Gain alone wouldn't do it, tho.
 

dshreter

Addicted to Fun and Learning
Joined
Dec 31, 2019
Messages
532
Likes
773
1) Is it possible to adjust a subwoofer's volume without constantly manually turning the knob on the subwoofer itself? Can this be done by using the high level binding posts on the sub? In what order would i hook up the speaker and the sub? I know SVS has an app to do this, but I wanted to know if there is a different way.
Yes, the high level inputs are one way. Many preamps also have a man additional volume controlled pre-out that is suitable for the sun’s low level inputs. Either way, volume is meant to be controlled by your preamp/amp and not from the subwoofer. Volume on the sub is only adjusted for initially integrating it with your main speakers.

2) How can one hook up 2 subs with just 1 amp?
It depends. Some subs support daisy chaining from one to the next. Otherwise you can use a Y splitter.

3) How can one make sure lower signals, e.g., below 80 hz, go only to the sub and not to the speakers? I rarely see amps that have high pass or low pass filters (if those are the proper terms)

Thanks in advance to everyone for their knowledge.
It depends what electronics you have. Some integrated amps and surround processors have this capability. Some subwoofers have this capability too.
 

posvibes

Active Member
Forum Donor
Joined
Jul 4, 2020
Messages
181
Likes
242
but why would you want to limit the sub's response?
Not having any experience with subwoofers and really no requirement for them as I am quite content with the bass from 2 way bookshelf speakers. I understand the requirement for those who want full range fidelity etc, I also have a 3 way floorstander that goes to 36Hz + or - xdB, although they get little used these day.

I was just curious if a subwoofer could be limited and if its a commercial of technical limitation that does not allow that control.

I never feel short changed with bookshelf speaker bass if they are good speakers and well voiced even if in some cases where the bass is limited to 70Hz say such as Harbeth P3 for example. I wonder how much truly useful bass is necessary below 50Hz for me and the way I listen and what I listen to. Thanks for clearing it up for me though @Chrispy .
 

Chrispy

Major Contributor
Forum Donor
Joined
Feb 7, 2020
Messages
4,274
Likes
3,222
Location
PNW
Not having any experience with subwoofers and really no requirement for them as I am quite content with the bass from 2 way bookshelf speakers. I understand the requirement for those who want full range fidelity etc, I also have a 3 way floorstander that goes to 36Hz + or - xdB, although they get little used these day.

I was just curious if a subwoofer could be limited and if its a commercial of technical limitation that does not allow that control.

I never feel short changed with bookshelf speaker bass if they are good speakers and well voiced even if in some cases where the bass is limited to 70Hz say such as Harbeth P3 for example. I wonder how much truly useful bass is necessary below 50Hz for me and the way I listen and what I listen to. Thanks for clearing it up for me though @Chrispy .

Was more curious what you're trying to achieve in any case, but hope it helped. Only reason I see to limit bass extension (i.e. lower frequency response) is if it is causing issues due to your home and proximity to others as low bass travels thru walls well. You may not even listen to much with such low frequency content to begin with, tho I listen to quite a bit of music with low frequency content, as well as movies. Personally I like my system capable of 10Hz :) Not that it comes into play frequently, but rather have it than not. I'm somewhat a bassoholic, too....my favorite part of the spectrum.

I wasn't sure you realized a lower frequency spec (usually an f3, f6 etc depending on sub) was a brick wall, either....and how much roll-off might be involved (or your room's inherent characteristics). One way to do limit the lower frequencies is to get dsp (like a miniDSP unit perhaps) that can put a high pass filter at an appropriate lower frequency to limit the sub's response like is sometimes done to limit excursion on ported subs below tuning.
 
Top Bottom