• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Another 8" dual opposed subwoofer project

ppataki

Major Contributor
Joined
Aug 7, 2019
Messages
1,325
Likes
1,530
Location
Budapest
After finishing my new DIY system in my home office/bedroom I have decided to also add (build) a subwoofer to it

I have really huge dips in the frequency response due to room modes; see the before/after DSP correction curve below:

1718098533581.png



When running REW simulations for adding a sub to the system, the resulting curve looks a bit better (highlighted):

1718099081635.png


So driven by curiosity I have decided to add a 8" dual opposed subwoofer (DOS) to the system

I will be using two Lavoce SSF082.00L 8-ohm drivers for the project (wired in parallel to get 4-ohm)
293-784_ALT_0.jpg

The system will look like this:
- current mains (Pluvia 11-based spheres) driven by a Topping PA7 Plus amp and an SMSL D-6 DAC
- I will add an RME Digiface USB digital-digital converter in the signal chain and connect the above devices to it
- Plus I will connect another D-6 DAC and a Fosi V3 Mono amp to the Digiface too (to drive the DOS)

Like this I will have fully discrete channels so I could apply DSP with maximum flexibility

I will post the DOS cabinet details later today, stay tuned!
 
I have really huge dips in the frequency response due to room modes; see the before/after DSP correction curve below:

1718098533581.png
Are you aware that flat in-room response is a flawed target?
https://youtu.be/_tnWB8Rl0Ms

Edit:
That is, for a typical far field system. Your DIY system OTOH appears to be near field, my apologies.
 
Are you aware that flat in-room response is a flawed target?
https://youtu.be/_tnWB8Rl0Ms

Edit:
That is, for a typical far field system. Your DIY system OTOH appears to be near field, my apologies.
No worries @staticV3
By the way this is not my target anyway, if you read the post that I linked above you will see that what I do is that I correct to flat and then I add totally custom shelf filters to 'voice' the lows and the highs to taste
This is what I do with all my systems and it works really well
 
Let's see the cabinet details now

1718105748113.png


Size will be 300x260x350 mm
Cabinet material is not yet decided but it will be either MDF or plywood or bamboo
The cabinet will be painted matte white and once done, I will add a 'beauty' front panel on both ends using Ikea magic :)

The speaker drivers shall arrive in 5-6 weeks' time - I might start the cabinet build sooner though

I will post updates as I progress
 
Some simulation curves for those that are fond of these

Approx. 250W will be the amplifier-limited maximum power output at 4 ohm
At 24Hz at 1 meter that will yield an SPL of 95dB (+ room gain)

1718106209769.png


Here the cone excursion will be at about 65% of the xmax of the driver so I would not expect much distortion

1718106473065.png


Group delay:

1718106521772.png


To me these all look really fine!
 
The cabinet is in progress:

20240613_195949.jpg


Finally we used pine wood panel with a thickness of 18mm
I know that this might not be the most optimal material but there was a bigger panel just lying around in the workshop, so..... :)

Next steps will follow as soon as the drivers arrive - best case scenario is mid-July, worst case scenario is end of August but I keep my fingers crossed
 
The drivers will arrive either next Friday or the following Monday.
I will post an update probably in two weeks' time
Stay tuned! :)
 
Today the drivers have finally arrived!

20240705_130307.jpg

20240705_130345.jpg

20240705_130353.jpg

20240705_130413.jpg


Both of them work fine, just tested them

Next week I will finish the cabinet (probably first without the 'beauty front panels'; those will come a bit later)
Will post pictures and measurements too!
 
Back
Top Bottom