Small to large PSA subs on the way, 2024 maybe

Have we already found out what the LF cutoff is expected to be for the FR5 stand mounted speakers?

Have seen nothing

Can @Paul share some features or design criterias? Parametric EQ (DSP or analog, how many bands), remote, low and high level inputs?

We’re still working on this model but bass extension will be 35 Hz (at -6 dB relative to the response at 200 Hz). We have designed the midwoofer (and associated 6x9" rear firing passive radiator) for low distortion and long excursion to still give reasonable output with this level of bass extension and so I think that a lot of people could be happy listening to a lot of music with this speaker without the use of a subwoofer, though high quality subwoofers could certainly enhance the performance too.


We are designing a purpose-built subwoofer offering with high end 2 channel music in mind. A subwoofer that sounds great in a musical context can also work great in home theater (assuming high output capability and good deep bass performance) but the converse is not always true - some of the best 'boom for the buck" home theater models are more difficult to get to integrate seamlessly in a music system (without a lot of work) and can tend to have some inductance/flux modulation issues and compression issues.

My work on this project thus far has been on the transducer side making some of the best high-performance woofers that we can with excellent linearity from a nonlinear distortion perspective, very high excursion (for clean deep bass output). I have developed multiple platforms (2.5", 3", 4" coils) and we are currently prototyping a 3" and 4" coil option using 10" diameter spiders (something capable of >3" p-p mechanical travel).

We already have great high-power class-D amplifier platforms in some of the work that was done for the stellar M700/M1200 products (and can scale that up further, as needed) and we are looking at the feature set for the input/DSP board. Certainly, high and low level inputs (and some sensible connector options for those). While DSP will be used for the internal design (EQ, limiting etc) we want to keep the external interface simple (gain, phase, flexible lowpass filtering, and some presets for different room sizes and deep LF contour).

I don’t think that many of our customers are using DIY measurement systems and manually setting PEQs. When using multiple subwoofers, this can get rather complicated and for those trying to individually adjust delays, PEQ etc. There are some outboard solutions that do a lot better job for multiple subwoofers (like Dirac Live bass control, and others).


Thanks so much Chris!
Do I understand right, you plan to use a DSP board (for other reasons) but don’t want to offer controls for parametric EQ because you think it overcharges customers?

Well, internally, subwoofers have to have their own internal EQ, limiting etc. and this can be done through analog or DSP but DSP makes the most sense for our application. The rear panel knobs and switches are actually adjusting DSP parameters etc.

However, to make this user accessible, it comes down to some additional hardware in the device (for wifi/bluetooth connectivity for the app/web interface to the device) but more so a significant software burden to make/maintain an app, getting it certified/submitted to app stores, ongoing testing on phone devices etc. That platform could represent a $100K investment or more. Folks like REL have been pretty successful without this feature (and focusing more on sound quality than features)

We could use a 3rd party amplifier solution with a pre-made applications (like Klipsch or Elac uses from Sonavox or M&K use from ACI) but that would preclude us from using our own amplifier platform (an area where we have some expertise and can get higher performance). We will likely still use this on less expensive models where a turnkey amplifier can offer better value.

However, it also comes back to the idea that basic signal processing in the subwoofer makes sense, but having an outboard controller for orchestrating room EQ may be the better solution to having it in-built (so you can consider the response of all of the LF sources in-room, including your speakers and multiple subwoofer where applicable).


Thanks, I understand the financial effort of maintaining a digital feature set and you’re probably right that few go the mile of measuring for setup…and yes external room EQ for the whole speaker system is an option, but that would mean the whole signal (not only bass) is digitized…not for everyone.
May it be digital or analog parametric EQ… what’s my experience with optimal setup of a sub is, that without that kind of EQ, one (with complete flexibility of positioning) may find a place where a main room node in the LF area doesn’t get too high, but then mostly another is still quite obvious or dips are too strong or numerous. And that’s the best case with maximum positioning flexibility …while in case of such an EQ, one‘s quite flexible in placement, can lift volume to an amount where most dips get quite flat while peaks can be pulled down with EQ, resulting in a quite flat FR with quite flexible placement options, which I wouldn’t want to miss.

But I also understand, your main focus is designing the best woofer. I just think the main challenge of a sub (no matter how good technically) is room integration and flat FR.


Well, I’m not saying that you need to digitize the whole signal (you can leave that analog, though if you have only digital sources like I do, I would recommend doing any processing there before your DAC anyway, not just at the subwoofer.

To really optimize a pair of subwoofer and main speakers over one or more listening positions is a lot more complicated than just plunking he subwoofers down anywhere and EQing them. Here’s a pretty good workflow explained using a miniDSP.

This isn’t a lot different than something like other EQ systems but it does take into account, the phase and delays of multiple subwoofers to get a flat in-room response over a wider listening area. This is not something that can be implemented inside a single subwoofer’s DSP and really requires a solution a step up the chain to integrate these multiple sources together.


Thanks Chris and yes, setting up multiple subs with something like miniDSP seems complex and I see, your concept is to use that external idea instead of offering a built in solution. I just guess that finally even less people will use that, compared to a built in EQ (which means, they have a worse situation than with a built in solution then. But miniDSP is definitely a fine approach.

Using processing before the DAC seems to make much sense, just if one reads about the influence and noise/jitter/clocking topics at this interface between streamer/transport and DAC, I doubt that’s without major downsides either

So as always we have to chose the way with the least disadvantages for our situation :wink:.