Wiim sub pro + fosi za3/wiim ultra

[elbigote]

Hey guys! First time here. Sorry if this question is dumb but I'm not very experienced and couldn't find the answer anywhere, and I don't want to mess this up.

My current equipment is as follows: Wiim ultra > rca to fosi za3 amp (stereo mode) > speaker cable to speakers (3 way custom built for a rich guy; sound wonderfully but no specs), and also wiim ultra > rca to wiim sub pro.

So far I'm very pleased with the setup. Today I got the wiim sub pro, and after setting it up, It managed to sound quite nicely and give a fuller sound overall. However, I have a doubt. I notice that (predictably) the volume knob in the fosi isn't "tied" to the volume of the subwoofer (which is controlled through the wiim app). So for instance if i put the knob on the fosi amp at 0, the sub remains playing music at the same volume it already was. This begs the question: is this supposed to happen? Is this a relevant issue? I figure it might be, so I thought of a possible solution. The fosi amp has a dedicated sub out so i could connect the sub with rca from there, but i don't see the option to connect it to anything other than the wiim ultra in the configuration from the app, and given the fact that the sub doesn't have physical knobs, I don't know if I would be able to manage the sub level and crossover frequency, etc., from the app if I do this connection. Maybe I can connect it to the fosi amp with rca, and still pair it to the wiim app so I can control the parameters? Or maybe it's unnecesary or dangerous to the device? (that's why I haven't tried it yet).

If anyone knows it would be greatly appreciated. And again, sorry if the question is too noob.

 

[Wiimer]

Hey guys! First time here. Sorry if this question is dumb but I'm not very experienced and couldn't find the answer anywhere, and I don't want to mess this up.

My current equipment is as follows: Wiim ultra > rca to fosi za3 amp (stereo mode) > speaker cable to speakers (3 way custom built for a rich guy; sound wonderfully but no specs), and also wiim ultra > rca to wiim sub pro.

So far I'm very pleased with the setup. Today I got the wiim sub pro, and after setting it up, It managed to sound quite nicely and give a fuller sound overall. However, I have a doubt. I notice that (predictably) the volume knob in the fosi isn't "tied" to the volume of the subwoofer (which is controlled through the wiim app). So for instance if i put the knob on the fosi amp at 0, the sub remains playing music at the same volume it already was. This begs the question: is this supposed to happen? Is this a relevant issue?

Hi
Adjust the volume in Ultra while maintaining the current connection.

I figure it might be, so I thought of a possible solution. The fosi amp has a dedicated sub out so i could connect the sub with rca from there, but i don't see the option to connect it to anything other than the wiim ultra in the configuration from the app, and given the fact that the sub doesn't have physical knobs, I don't know if I would be able to manage the sub level and crossover frequency, etc., from the app if I do this connection. Maybe I can connect it to the fosi amp with rca, and still pair it to the wiim app so I can control the parameters? Or maybe it's unnecesary or dangerous to the device? (that's why I haven't tried it yet).

When connecting a subwoofer to the sub out of the Fosi amp, you will no longer be able to manage bass using the Ultra. As mentioned earlier, I recommend connecting the subwoofer to the Ultra, keeping the Fosi volume fixed, and adjusting everything through the Ultra.

 

[elbigote]

Thanks m8 for the quick answer. Will leave the connection as is then. Maybe I was overcomplicating things a bit too much.

 

[harkpabst]

It's just important to not touch and change the volume level on the ZA3, once you have the subwoofer level set to your liking. You really must use only the WiiM Ultra volume control from this point on and just use the ZA3 as a power amplifier.

 

[elbigote]

Thanks for your answer. I ended up having the za3 fixed at 9 o'clock and manage everything with the volume control from the Wiim ultra. I previously read I should have the za3 fixed at Max but that was somehow not working very well because I can't listen to music that loud and had to use the wiim volume at like 20.

 

[harkpabst]

Thanks for your answer. I ended up having the za3 fixed at 9 o'clock and manage everything with the volume control from the Wiim ultra. I previously read I should have the za3 fixed at Max but that was somehow not working very well because I can't listen to music that loud and had to use the wiim volume at like 20.

Yes, it's certainly a good idea to keep the volume setting on the Ultra somewhere around 50 % or higher for your usual listening levels. Since you don't need the maximum power anyway, you could also leave the ZA3 volume control at 100 % and reduce the maximum output voltage of the WiiM Ultra instead.

The main benefits of keeping the ZA3's volume control at max are:

• This position is 100% reproducible, no guesswork, turn it fully up and you're done.
• Setting the potentiometer to max effectively connects the output of the pot directly to the input, bypassing the resistive track as the weak point.

Fosi don't provide very detailed technical information, but we can use the measurements from the ASR review. The maximum undistorted power output into 8 ohm is 90 W per channel. The amplifier's gain (RCA inputs, volume knob at 100%) is ~26,05 dB, so the output voltage is 21,1 times the input voltage. Thus, the input sensitivity (the input voltage required to reach max. undistorted power) is 1,27 V. The default setting for maximum output voltage of the WiiM Ultra is 2 V. That's a lot more than required.

If you set the maximum output volume of your WiiM Ultra to 1 Vrms instead of 2 Vrms in the audio settings, you would still be able to get a power output of ~56 W. 56 W might sound a lot less than 90 W, but the difference in maximum sound pressure level is just 2 dB. With the current volume setting on the ZA3 you're also restricting it's power output, so this is not really a difference.

 

[elbigote]

Yes, it's certainly a good idea to keep the volume setting on the Ultra somewhere around 50 % or higher for your usual listening levels. Since you don't need the maximum power anyway, you could also leave the ZA3 volume control at 100 % and reduce the maximum output voltage of the WiiM Ultra instead.

The main benefits of keeping the ZA3's volume control at max are:

• This position is 100% reproducible, no guesswork, turn it fully up and you're done.
• Setting the potentiometer to max effectively connects the output of the pot directly to the input, bypassing the resistive track as the weak point.

Fosi don't provide very detailed technical information, but we can use the measurements from the ASR review. The maximum undistorted power output into 8 ohm is 90 W per channel. The amplifier's gain (RCA inputs, volume knob at 100%) is ~26,05 dB, so the output voltage is 21,1 times the input voltage. Thus, the input sensitivity (the input voltage required to reach max. undistorted power) is 1,27 V. The default setting for maximum output voltage of the WiiM Ultra is 2 V. That's a lot more than required.

If you set the maximum output volume of your WiiM Ultra to 1 Vrms instead of 2 Vrms in the audio settings, you would still be able to get a power output of ~56 W. 56 W might sound a lot less than 90 W, but the difference in maximum sound pressure level is just 2 dB. With the current volume setting on the ZA3 you're also restricting it's power output, so this is not really a difference.

Thanks for the detailed help, man. I'm going to try it tomorrow with the 1vrms setting and za3 maxed. It would have never occurred to me. Is that what you would do? It makes sense

 

[harkpabst]

Thanks for the detailed help, man. I'm going to try it tomorrow with the 1vrms setting and za3 maxed. It would have never occurred to me. Is that what you would do? It makes sense

Well, yes, personally that's how I would do it. If you still feel the usable range of the Ultra's volume control to be limited (because it's too loud) you can even reduce the max output voltage to 800 mVrms.

The volume pot of the ZA3 is a logarithmic taper type (als opposed to a linear taper type). This is very common with audio amplifiers because it represents our hearings sensitivity to sound pressure changes better than a linear potentiometer. But this also means that a a small twist on the knob will have a different effect, depending on how far you turned the knob already.



In the lower volume region (where channel imbalance tends to be worst) you need to turn the knob quite a bit to get a difference in output at all. In the higher volume range even small variations of the position of the knob will have a relatively big impact. That's why I personally prefer to have the volume knob in the well-defined max position in a scenario where the balance between the subwoofer and the main speakers can be upset if for whatever reason you change the position of the amplifier's volume knob.

Others might or might not agree. Hey, we're on the Internet.

 

[elbigote]

Well, yes, personally that's how I would do it. If you still feel the usable range of the Ultra's volume control to be limited (because it's too loud) you can even reduce the max output voltage to 800 mVrms.

The volume pot of the ZA3 is a logarithmic taper type (als opposed to a linear taper type). This is very common with audio amplifiers because it represents our hearings sensitivity to sound pressure changes better than a linear potentiometer. But this also means that a a small twist on the knob will have a different effect, depending on how far you turned the knob already.

View attachment 33872

In the lower volume region (where channel imbalance tends to be worst) you need to turn the knob quite a bit to get a difference in output at all. In the higher volume range even small variations of the position of the knob will have a relatively big impact. That's why I personally prefer to have the volume knob in the well-defined max position in a scenario where the balance between the subwoofer and the main speakers can be upset if for whatever reason you change the position of the amplifier's volume knob.

Others might or might not agree. Hey, we're on the Internet.

Hey! Sorry for the late reply. Your explanation makes total sense. I tried it and I feel like I'll have do the subwoofer setup again but now starting with the 1vrms and za3 at Max setting (which will definitely be the setting I'll be using), because when I use it that way right now, I feel it sounds different than with the 2vrms and za3 @9 o'clock configuration. It might be subjective, I don't know, but I guess this is a lot of trial and error until we get to an optimal, happy configuration. To be honest, it has been difficult to arrive to a satisfying configuration, but I know it just needs more tinkering, and I have been especially busy.

Thank you so much for your guidance