This makes me want to get a pair of these: https://hadex.cz/spec/q378.pdf put them each on a simple baffle and stick into the corners
Specs look good for it.
GM
My experiment with an H-type open-baffle solution showed no decrease in room resonances, and an additional one caused by the H-structure. I think there's a reason why you hardly ever see in-room response curves for dipole bass solutions
The Subwoofer DIY Page v1.1 - Projects : An INF10 Dipole Subwoofer
Fewer modes are excited by a dipole subwoofer in comparison with a monopole subwoofer in the same position of the room.
See publication 21 of S. Linkwitz for a more detailed explanation (there is also a letter to the editor of JAES) here:
Linkwitz-Publications
What does "fewer" actually mean? One? Two?
My albeit limited test didn't disclose any significant improvement wrt modal impact on the measured response. The best way to treat the impact of room modes on a speaker's response remains to treat the room, not change the type of speaker.
Not in my opinion. After an easily reached point (i.e. stuffing the box with polyester fiberfill), the room has a significantly greater adverse impact on the response.
I think it is clear what "fewer" means, at least in mathematics.
I will copy from Linkwitz what he believed about the difference of monopole and dipole bass reproduction:
"As a hypothesis, consider that the combination of three effects might explain the bass clarity of dipole woofers. 1. A dipole's directional polar response excites fewer room modes. 2. Its total radiated power is 4.8 dB less than that of a monopole for the same on-axis SPL. Thus the strength of the excited modes is less. 3. A 4.8 dB difference in SPL at low frequencies is quite significant, due to the bunching of the equal loudness contours at low frequencies, and is more equivalent to a 10 dB difference in loudness at 1 kHz"
Exactly, that is a HYPOTHESIS.
Let's see the actual measurements to back it up. I did not see that in my measurements.
I've been experimenting with two woofers on small baffles hinged so as to compare the speaker as shown in the first post from Linkwitz's site and then opened out so as to form a dipole at 45 degrees into the corner. As expected the second way provides more output due to a single null as opposed to two only 45 degrees apart.
It is not that. Read carefully.
The hypothesis concerns the explanation of the bass clarity of the dipole woofers.
It is a fact that "The dipole's directional polar response excites fewer room modes".
In a JAES article by Linkwitz, there are a lot of measurements about this.
Fewer room modes does not necessarily mean better. It can also be that the axial modes in one dimensions can be very dominant. This can leave huge peaks but also nulls in the response, which can't be corrected. The multisub approach does just the opposite; exciting more room modes for a more even response. It concurs with my experience with dipole and cardiod subs; they're different but not better.
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