AVR for 2.1 HiFi?

[lovinthehd]

Consider a slot type port...makes the box bigger but....

 

[Kingnoob]

Hey guys,
After a while I come with some news.
I purchased a NR1403 that fit my needs. I can now :
- play music: signal comes from my chromecast audio through the amplifier unaltered (direct mode) to my power amps.
- watch movies in stereo mode with the signal downmixed to 2.0

I am now going to buy a RSS315HF-8 and put it in a 60L closed cabinet.

Final step will be the addition of a minidsp 2x4HD to handle the XO of the speakers + DSP + linkwitz transform to the subwoofer.

I'll give news. And pictures when everything is done.

Again, many thanks for your help !!

Good luck show some pics when it’s done, building a diy sub box is challenging. I sure couldn’t do it myself , didn’t put enough bracing in mine. Made it too large to bring downstairs, no way parents letting me put it down here .
I’ll probably be not be trying it again.!
I didn’t cut the wood, sound fine just too big, can’t even remember how I’d did it exactly.

 

[_Alex_]

Consider a slot type port...makes the box bigger but....

I did on winISD. Unfortunatly the result was the same: a port way way top long. I must have missed something but I can't figure out what...
It's not the first sub I design and I didn't have such a problem with the others.

 

[lovinthehd]

I did on winISD. Unfortunatly the result was the same: a port way way top long. I must have missed something but I can't figure out what...
It's not the first sub I design and I didn't have such a problem with the others.

How long? What height?

 

[highfigh]

To nitpick I'd say most towers can play down to 20 Hz but just not very loud.

Most speakers reach into the mid-low 30 Hz range, but even then, the -3dB point and downward slope in the 50Hz-40Hz area makes a subwoofer a good idea IF someone wants 20Hz. If they don't want or need that, full range should be fine. It's still good to have the option, though. Another reason <35Hz might not be wanted is in multi-family housing or when the buildings are close enough that the bass will intrude, especially when the construction does absolutely nothing to stop it.

 

[_Alex_]

How long? What height?

I calculated the effective inner volume which is 64L maximum.
If I want to keep air velocity < 20m/s and have an acceptable curve of response, I need to design a port tuned very low (10Hz) --> a round vent of slot type of 5*80 cm would be OK but the gain is not so big VS a closed box
If I want to design a slot port on one of the face of the box (let say 40cm), 5 cm opened, it should be 1m long ... to get the same result than the round but with a 1st port resonance at 18Hz...
Blue = Closed
Green = vented

What's the problem with Linkwitz Transform? I planned to do it that way --> F3=25Hz

 

[everettT]

I calculated the effective inner volume which is 64L maximum.
If I want to keep air velocity < 20m/s and have an acceptable curve of response, I need to design a port tuned very low (10Hz) --> a round vent of slot type of 5*80 cm would be OK but the gain is not so big VS a closed box
If I want to design a slot port on one of the face of the box (let say 40cm), 5 cm opened, it should be 1m long ... to get the same result than the round but with a 1st port resonance at 18Hz...
Blue = Closed
Green = vented

What's the problem with Linkwitz Transform? I planned to do it that way --> F3=25Hz
View attachment 59400

The drivers total Q is below .45 which is on the low side for a transform and would need a slightly smaller box to raise the qts. Which spreadsheet or program did you use to calculate the transform? I think the UM series driver from Dayton would be a better choice in a sealed alignment with a transform.

What are your goals with the subwoofer; Maximum extension, max SPL, or max fidelity? If extension and SPL what is your desired goal? Model the the driver with a PR instead of a vent and I think that will solve your issues, getting you a mid 20s F3 while keeping distortion down from 35hz and up in a small box.

 

[_Alex_]

Thanks for you reply,

The drivers total Q is below .45 which is on the low side for a transform and would need a slightly smaller box to raise the qts. Which spreadsheet or program did you use to calculate the transform?

I used a spreadheet you can find here:
https://www.minidsp.com/forum/software-support/16516-biquad-filter-spreadsheet
It's the one of miniDSP because I plan to get the miniDSP 2x4HD.
Again, forgive my ignorance, but what would be the problem with a low Q?

I think the UM series driver from Dayton would be a better choice in a sealed alignment with a transform.

Unfortunatly, my current amp (behringer A800) can't hold 4 ohm bridged. But I can change it if necessary.

What are your goals with the subwoofer; Maximum extension, max SPL, or max fidelity? If extension and SPL what is your desired goal? Model the the driver with a PR instead of a vent and I think that will solve your issues, getting you a mid 20s F3 while keeping distortion down from 35hz and up in a small box.

Well. I would like to have qualitative bass. I mostly listen to music, and sometimes watch movies.
I don't need that much SPL, I never listen to music or movies at very high levels. Music = around 80dB, Movies a little bit more. I do not need a 110db peak proof subwoofer.
Regarding extension, I first wanted to reach 20Hz @ F3. But with the volume that I have now, I wish I could reach mid 20 @ F3. If not possible, then 30Hz will just be fine.
I cannot put a PR either, because only 1 of the panel of the box can hold a transductor. The others will be "decorated" to match the living room.

And if this sub definitly don't match, I'll just find another one working in 60L.

 

[everettT]

Thanks for you reply,



I used a spreadheet you can find here:
https://www.minidsp.com/forum/software-support/16516-biquad-filter-spreadsheet
It's the one of miniDSP because I plan to get the miniDSP 2x4HD.
Again, forgive my ignorance, but what would be the problem with a low Q?


Unfortunatly, my current amp (behringer A800) can't hold 4 ohm bridged. But I can change it if necessary.


Well. I would like to have qualitative bass. I mostly listen to music, and sometimes watch movies.
I don't need that much SPL, I never listen to music or movies at very high levels. Music = around 80dB, Movies a little bit more. I do not need a 110db peak proof subwoofer.
Regarding extension, I first wanted to reach 20Hz @ F3. But with the volume that I have now, I wish I could reach mid 20 @ F3. If not possible, then 30Hz will just be fine.
I cannot put a PR either, because only 1 of the panel of the box can hold a transductor. The others will be "decorated" to match the living room.

And if this sub definitly don't match, I'll just find another one working in 60L.

I'm on the road tonight but a question or a thought, unless you were placing the driver at the bottom of the box, a PR should still be an option, correct? Trying to uncomplicate your situation. Maybe @TLS Guy has some experience with this driver and can chime in

 

[everettT]

Thanks for you reply,



I used a spreadheet you can find here:
https://www.minidsp.com/forum/software-support/16516-biquad-filter-spreadsheet
It's the one of miniDSP because I plan to get the miniDSP 2x4HD.
Again, forgive my ignorance, but what would be the problem with a low Q?


Unfortunatly, my current amp (behringer A800) can't hold 4 ohm bridged. But I can change it if necessary.


Well. I would like to have qualitative bass. I mostly listen to music, and sometimes watch movies.
I don't need that much SPL, I never listen to music or movies at very high levels. Music = around 80dB, Movies a little bit more. I do not need a 110db peak proof subwoofer.
Regarding extension, I first wanted to reach 20Hz @ F3. But with the volume that I have now, I wish I could reach mid 20 @ F3. If not possible, then 30Hz will just be fine.
I cannot put a PR either, because only 1 of the panel of the box can hold a transductor. The others will be "decorated" to match the living room.

And if this sub definitly don't match, I'll just find another one working in 60L.

I'm back home this afternoon and will model the PR with your box size if the woofer or PR can be placed underneath the box with your decoration requirements. If not this driver would be better in a sealed alignment and you can wire it to 4ohm. Just note power requirements are much larger for the sealed box with EQ as opposed to vented or PR alignment.

CLEARANCE Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per Coil

Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per CoilDayton Audio UM12-22 12" Ultimax DVC SubwooferExperience the Apex of Subwoofer DesignThe Ultimax Series of dual voice coil subwoofers, from Dayton Audio, are not for the faint of heart. Built using the latest in subwoofer technology...

www.parts-express.com

 

[_Alex_]

I'm back home this afternoon and will model the PR with your box size if the woofer or PR can be placed underneath the box with your decoration requirements. If not this driver would be better in a sealed alignment and you can wire it to 4ohm. Just note power requirements are much larger for the sealed box with EQ as opposed to vented or PR alignment.

CLEARANCE Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per Coil

Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per CoilDayton Audio UM12-22 12" Ultimax DVC SubwooferExperience the Apex of Subwoofer DesignThe Ultimax Series of dual voice coil subwoofers, from Dayton Audio, are not for the faint of heart. Built using the latest in subwoofer technology...

www.parts-express.com

Good discount ! Unfortunatly, I live in Europe.
Power can be limitating, but what scares me more is xmax. I didn't find a tool that predict the cone excursion after EQ.

 

[dalotissac]

The AVR will do the job you want and the Speed Test future job of home theater if you choose to go that way. Having an AVR is not necessary for implementing a subwoofer. Most subs have binding posts and low pass filters so that you can put it between the amp and the speakers.

 

[ryanosaur]

Most subs have binding posts and low pass filters so that you can put it between the amp and the speakers.

This is not necessarily true.
Some subs, do.
A majority will have RCA and XLR inputs. I think I've even seen one sporting a Toslink input.

In the use case of utilizing Speaker-level Input, this is a feature that a user should be shopping for specifically to narrow down choice of Sub.