Help in understanding impact of Bass/Treble of Amplifier on high level connected Subwoofer

swamytk

Active Member
Joined
Apr 18, 2019
Messages
453
Points
43
Location
Pune
It is my understanding that Bass/Treble controls volume of individual frequency range. In a typical 2.1 setup which I am planning to setup, Subwoofer High Level input connected to Amplifier Speaker output. In this case, Will the Bass and Treble control on Amp be effective on Subwoofer performance also? For example if I reduce Bass of Amplifier, will it cut low frequency (reduce volume of low frequency exactly speaking) in Sub. If Sub takes only signal from high level input, it shouldn't affect Sub performance, right? Can some one clear this?
 
Last edited:
Frequencies of bass tone control which drop within the cutoff frequency of subwoofer will be affected and remaining will be pass to main speakers as it is. Treble controls may not affect as these frequencies will not be within the subwoofer cutoff frequency.
 
Yes it should. Line level is a different story
Frequencies of bass tone control which drop within the cutoff frequency of subwoofer will be affected and remaining will be pass to main speakers as it is. Treble controls may not affect as these frequencies will not be within the subwoofer cutoff frequency.

Sub takes just signals only, right? So it should not be affected by lower volume of low freq band due to bass knob goes anticlockwise?
 
Which subwoofer are you using? Bass control on the amp will impact the sub input dependent on the crossover point and the bass bandwidth and attenuation level of the control on the amp.
As there is no bandpass or parametric equalization to control a particular range of frequencies, any + or - effect on the bass control on the amp will impact a wider frequency range due to the limitations of the design.
So if your crossover point is low enough, the impact could be that much less.

Then again, some companies like REL have a de-equalization circuit on its high level inputs which cleans up.the input before convertion to low level signal for further amplification. Such companies recommend using only high level inputs.
 
Which subwoofer are you using? Bass control on the amp will impact the sub input dependent on the crossover point and the bass bandwidth and attenuation level of the control on the amp.
As there is no bandpass or parametric equalization to control a particular range of frequencies, any + or - effect on the bass control on the amp will impact a wider frequency range due to the limitations of the design.
So if your crossover point is low enough, the impact could be that much less.

Then again, some companies like REL have a de-equalization circuit on its high level inputs which cleans up.the input before convertion to low level signal for further amplification. Such companies recommend using only high level inputs.
Here is my current setup:
Stereo Amplifier: Marantz PM5005 (Power Output (8 / 4 Ohm RMS): 40 W / 55 W and Frequency response: 10 Hz-50 kHz)

Stereo Speaker: Wharfedale Diamond 220 ( 5.1" woofer, Frequency response (+/-3dB): 56Hz - 20kHz and Sensitivity(2.83V @ 1m) 86dB)

Subwoofer to be added: Yamaha YST-315 has Bass, High cut (40Hz - 140Hz), Phase and Volume Control. Freq Resp of 20 Hz - 160 Hz (–10 dB)
 
Which subwoofer are you using? Bass control on the amp will impact the sub input dependent on the crossover point and the bass bandwidth and attenuation level of the control on the amp.
As there is no bandpass or parametric equalization to control a particular range of frequencies, any + or - effect on the bass control on the amp will impact a wider frequency range due to the limitations of the design.
So if your crossover point is low enough, the impact could be that much less.

Then again, some companies like REL have a de-equalization circuit on its high level inputs which cleans up.the input before convertion to low level signal for further amplification. Such companies recommend using only high level inputs.
@Kannan Good, thanks. So let us assume I set Sub crossover at 65hz and Amp Bass control just plays with above 65 only. In this case Sub doesn't have any impact. Please confirm my understanding.
 
[...]So let us assume I set Sub crossover at 65hz and Amp Bass control just plays with above 65 only. In this case Sub doesn't have any impact. [...]

Your stereo amplifier has no knowledge of the downstream crossover setting in your sub. So, any bass control you apply to the stereo signal will be seen by the sub. That's my understanding of your situation, at any rate.
 
@Kannan @liverpool_for_life I found following in specification of Marantz PM5005 Stereo Amplifier:
Tone Control:
BASS (100 Hz) : ±10 dB
TREBLE (10 kHz) :±10 dB

How to understand this? I would like to know which bass frequency range it controls.
 
Don't worry about it. The effect will be hardly felt. Ideally leave the tone controls at center position, so that nothing is added or removed.

Since the sub is going to rely on the signal coming from amp, it's best to provide it with as clean a signal as possible. The sub would be internally converting the speaker level signal to low level signal. If you add tone controls, this conversion could give weird results. So try to mimic the signal that could be same as an rca low level signal.

When is the sub coming?

MaSh
 
No real description in the manual either. I’d imagine the given specifications suggest that bass controls will work from 100 Hz onwards down and the treble controls from 10K onwards up.

Exactly!

Just reading about something called Shelving. As per Wiki:
Shelving controls are usually simple first-order filter functions which alter the relative gains between frequencies much higher and much lower than the cutoff frequencies. A low shelf, such as the bass control on most hi-fi equipment, is adjusted to affect the gain of lower frequencies while having no effect well above its cutoff frequency. A high shelf, such as a treble control, adjusts the gain of higher frequencies only. These are broad adjustments designed more to increase the listener's satisfaction than to provide actual equalization in the strict sense of the term.​

So as per this my amp can
1. Bass knob adjusts from +10db --> 0db --> -10db for anything below 100Hz
2. Treble knob adjusts from +10db --> 0db --> -10db for anything above 10KHz
 
Don't worry about it. The effect will be hardly felt. Ideally leave the tone controls at center position, so that nothing is added or removed.

Since the sub is going to rely on the signal coming from amp, it's best to provide it with as clean a signal as possible. The sub would be internally converting the speaker level signal to low level signal. If you add tone controls, this conversion could give weird results. So try to mimic the signal that could be same as an rca low level signal.

When is the sub coming?

MaSh
Thanks for the input. Sub is not yet shipped. htstore is supposed to ship it by tomorrow.
 
I think if Bass is boosted @ 100hz, then it will be around that point only.If we increase bass in amp, then we can hear certain Bass frequencies getting boosted and not all range. If amp has 50hz boost ,then may bass sound different than that of 100hz boost. Just like equiliser, bass is getting boosted near specified frequency which is 100hzs here.

Now as FMs said, amp will send the boosted bass signal to SW and then its plate amp settings will take over.If filter is set at 80hzs in SW, then 100hz frequencies are missed.
Treble is not possible to affect SW sound.
 
Shelving is the attenuation curve...at 6db/100hz, the impact could go till 50hz, at 12/100 till about 63, at 18/100 around 75hz and at 24/100, very little down 100.
These are purely technical.

Overall at 100hz, with your sub xo at 50 and below, you can ignore impact of bass control on the amp. For around 63 it will be infiticimal at 18 and 24. My guess is most subs have a default slope of around 12db.

One easy way to assess by listening is to switch between pure direct and normal modes after turning in your subwoofer to the mains
 
The crossover in the sub is not a brick wall filter. So, no. 100 Hz will not be "missed". The sub will see a 100 Hz signal, albeit at a reduced level which is dependent on the slope in the crossover implementation.
Yes, true. I realized this with Yamaha Sub (which I returned immediately due to damaged unit). While playing with this unit I set 140 as crossover, I can hear some voice and other mid range too in bad quality. After all they are all analog, not digital to cut off.
 
Usually subwoofer crossover is set at 20% higher than the lower frequency response of connected speakers. In this case as your speakers have lower frequency response is 56Hz , then you may set subwoofer crossover to 70 Hz. Generally speakers are not able to reproduce their lower or lowest frequencies faithfully to optimum level. Its better to let subwoofer to take control below that. If you set high crossover to subwoofer than your sound stage will become weak as two channels information you are feeding in subwoofer. Subwoofers are usually used in stereo set to produce that frequencies which main speakers can't produce faithfully and in this was subwoofer adds low end extension without affecting the main frequency band.
 
Purchase the Audiolab 6000A Integrated Amplifier at a special offer price.
Back
Top