Will sub's be encouraged in a 2-channel set-up with the FR30's?

I predict the official position will be, “All speakers can benefit from the addition of one or more subwoofers, but you certainly will not need subs with these FR30s”

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Yes, or maybe “the FR30 may benefit from the addition of one or more subwoofers depending on an abundance of negative acoustic properties in your listening room.

Subs are always needed for the most complete full range sound and least impact of room modes. Room modes always exist and can only be reduced in impact, never eliminated. The physical location in the space for the mains for best imaging is very rarely the same as the best locations to smooth room modes.

I believe one could argue don’t make the mains full range. The bass there could do more harm than good.

I’m running into this currently and one of the drivers (pun intended) to go search out new speakers. There is a slight peak on my mains which is only made worse by adding subs but I cannot determine a way to get the mains to calm down. Maybe bass traps right near the radiators? Still experimenting… but ultimately I want new speakers anyway. Everyone talks about integrating the subs to the mains (which would really require notch filters). What about knobs on the mains to integrate the subs. Few speakers allow for this.

I’ve found it’s so much vastly less effort to drive the subs the same high level signal as the mains to blend them. REW is your friend to measure amplitude, xover and as important if not more so, phase/delay.

I start out measuring each sub independently to get a ‘picture’ of the response, then both together, then add the mains and dial in each sub phase to smooth the response as much as possible. Then the final touch is convolution filters!

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Something that is addressed by my Infinity bass controls. No need for subs here…image|666x500

Get 2 Rel Subs. You won’t regret it with any speaker.


According to Paul:


From my experience also with speakers much bigger than the FR 30, the fact that they go down deep doesn’t mean much in practice. Reason is, that it would be pure luck with very low chance, if they would cover the area of the frequency needed, at the place they are positioned for soundstage reasons. Even if, they’d quite sure produce a noticeable suck out at another frequency around.

Even if you’re able to flexibly position a sub in the room, you’re only able to flatten its response at a prioritized frequency +/- 5-10 Hz. To get it flat enough in its whole spectrum, the sub must additionally be EQ’able. Otherwise you have to work against remaining peaks with decent room treatment.

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I’d be willing to bet that a large majority of those who do have a couple of subs don’t actually achieve that flat response in their rooms.

Really flat is certainly quite impossible, but without noticable peaks from 20-100Hz and just one or two noticable dips not more than 10Hz wide is achievable and quite “flat” audibly.

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Or even better 4!


A good piece on why sonic clarity is more desirable than a flat frequency response.


I’m not advocating the use of subs to achieve a flat frequency response. I understand a truly flat speaker may not actually sound musical. I’m just saying (as is Paul about his FR-30’s), I don’t feel my speakers need external subs. My speakers have the capability for multiple EQ woofer adjustments and it works rather well. It allows me to concentrate placement that’s ideal for the mid range and tweeter, then compensate for the bass output for a less than ideal woofer placement. Everybody’s system could be made “better” by some change, enhancement, or augmentation, but despite my system being in an 800sf room, I don’t have issues with it’s bass reproduction (and I am into percussion).


Totally understand. I was just trying to remind folks that you can have a noisy room with flat frequency response with or without subs. A noisy non diffused room normally lacks sonic clarity.


Ah, I was not so swift to pick up on that point. Full agreement.

This is another good piece from the folks at Acoustic Science Corporation. I like the way they talk about the timing of the notes we hear. I find their monthly emails are helpful reminders of the importance of room treatments.


Well, I would agree with many points of this discussion for sure.

We’re still preparing some marketing materials on the FR-30 but I can share that the low frequency cutoff is -6 db at 27 Hz. With a reflex/passive radiator enclosure, the roll-off below this is rather steep but you’ll see typically see extension from 20-25 Hz in-room. Still, as other mention, the benefit of multiple subs/ LF sources will help smooth the response wider listening area.

Please keep in mind that, if you listen to dynamic music in the bass and want a subwoofer that “keeps up” with the speaker, you’ll need something pretty potent. A pair of FR-30, with their 8 x 8" woofers and 8 x 10" passive radiators is capable of ~120 dB (in half space) from 25 hz and up with (when driven with 600 watts x 2) at the klippel rated Xmax of the woofers. Of course, you won’t want to listen full range at that level, but the system is certainly capable of it in the low frequencies, so that it has very low distortion at more moderate levels and a feeling of effortless bass dynamics.


Sounds pretty impressive for sure!

I fully understand the concept of “keeping up” because, as frequency descends from the mains, each octave lower requires an exponentially larger air moving capability. As an example, in my system, the “mains” are dual 12’s, and the low frequency section consists of 8x15’s per side. Currently using 72 Hz as the cross-over point.