Adding a second different sub

[Ofer]

I apologize in advance this is going to be a bit long.
Short intro,
About 2 years ago I hastily (stupidly) decided to boost my low end by adding a subwoofer. I bought an OEM 18" PA subwoofer. Little did I know that PA subwoofers (no matter how big) are tuned for music bass and mid bass only. Anything below 40hz is not interesting in that respect. My mains in my 3-way three amp system the 10" woofers are in a large ported cabinet that play down to 20hz ~-5db but they just do not produce that deep base. See below.

See added screenshots: Blue - woofer, red - PA sub.
That means to boost the low end it would be best if they could play together. As a separate sub channel it is nearly impossible to do. If one plays with the xover curve it is possible to have some overlap between the sub channel and the mains bass channel. What I opt to do is treat the sub channel as the bass channel and the mid woofers as lower midrange. In my sound-card channels 7/8 are from the same output jack so L+R were routed to the base.

In this setup the sub and mains overlap over the 40-100hz lower midbass region where the PA sub adds deep smooth base. It sounds great.
Now the disease hit again and I want to add a subwoofer that goes really low to the 20s. I haven't bought/built is yet.
My main goal is to have both subs overlap my mains and boost their lower bass. As you can't treat the bass channel/sub as a discreet channel and add both HPF and LPF I seek advice as how to do that. In short once arrived the current PA sub should sum the L+R and play 40-100hz and the new HT sub should sum L+R and play 20-100hz. My RME has 8 channels total. Is there a way do that?
Thanks for hanging in there and for any advice.
All screenshots were done from my office PC not the DSP PC where the measurements were really done.

 

[juicehifi]

You could configure the two subs as a two channel sub. That should give you a lot of design freedom with regards t how much he two share the load.

You could also sell your current sub as it seems somewhat unfit for the task. If I saw a higher sensitivity there I might have recommended a strong boost from 20-50 Hz. Some of the pro elements can do domestic deep bass with ease even though they appear to be mostly upper bass/lower midrange in a pro environment. But here, the sensitivity seems to fall short.

 

[Ofer]

You could configure the two subs as a two channel sub. That should give you a lot of design freedom with regards t how much he two share the load.

Didn't think of that. Could you please elaborate on how to do that?
Selling is an option for sure. The new sub is based on the Mart Cube with a Dayton audio 18" ultimax that is supposed to produce powerful deep base.
You mean something like this:

So driver 0 is the HT sub that has no HPF and a LPF of 100hz, Driver 1 has HPF of 35hz and no LPF. In the PA sub it is possible to add an LPF using the plate amp. The question is with no LPF how would AL treat the crossover/LPF that is introduced by the sub itself. Would AL try to correct that drop as there is no LPF for that driver?
Hope I am making myself clear.

 

[juicehifi]

Yes, exactly.

Some experimenting over that theme should give you a good result

 

[Ofer]

Can you please address this question:
The question is with no LPF how would AL treat the crossover/LPF that is introduced by the sub itself. Would AL try to correct that drop as there is no LPF for that driver?
Will AL try to boost the signal once it starts droping do to the LPF that was introduced by the sub but no by AL?

 

[juicehifi]

Lpf = low pass filter?

 

[Ofer]

Yes

 

[juicehifi]

Audiolense low-passes any sub in any configuration.

 

[Ofer]

Hi Brent,
I feel like I am missing something, probably do to my ignorance in how AL works. If we look at the 2 subs configured as one sub with 2 drivers as you suggested above. The HT sub has only a LPF so it plays from 10-100hz that is fine. The PA sub (driver 1) has only a HPF so it plays from 35hz-20000(?). see below.


If I add a crossover on the PA sub itself, as I can't add one in AL, Lets say at 90hz it will probably measure like this below:

My question is: Will AL try to correct this sub because in the software it has no LPF? will the dropping signal above 90hz be boosted to fit the crossover curve for that driver that is essentially 35-20000hz?
Thanks.

 

[juicehifi]

Al gives the subs several low passes.

1) high up on the speaker tab. This one only applies to material router directly to the sub.
2) on the speaker tab, bass offloading of each spraker.

Anything you do outside Al is subject to correction. I advise to turn off all external dsp that can be turned off.

 

[Ofer]

OK, so no point in applying xover in the PA sub.
How will I give two subs the same LPF and different HPF?


How will the above play out? what Low pass filter will sub driver 1 have?
Is it even possible what I am asking for?

 

[juicehifi]

Yes you can do something like that. You can also highpass one and not lowpass the other.

 

[Ofer]

Yes you can do something like that. You can also highpass one and not lowpass the other.

What will happen to the one I don't lowpass? won't AL try to correct it once the FR starts to roll of?

 

[jjazdk]

What will happen to the one I don't lowpass? won't AL try to correct it once the FR starts to roll of?

Why don't you look at the correction filters, they will show you exactly what AL will do.

 

[Ofer]

Why don't you look at the correction filters, they will show you exactly what AL will do.

I don't have the sub yet and was looking for advice as to how to configure it correctly with my other sub as discussed in the beginning of the thread.