Biblob
Addicted to Fun and Learning
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I mean the former, yes.Do you mean high pass the monitor at 80 Hz and low pass the sub at 80 Hz?
Would it be problematic because of the porting?
I mean the former, yes.Do you mean high pass the monitor at 80 Hz and low pass the sub at 80 Hz?
The manual of my B&W PV1d sub suggests to choose a crossover frequency at the -6dB point of the main speakers and choose a 12dB 2nd order slope for sealed main speakers (and 180 degree phase) and 24 dB 4th order slope (and 0 degree phase) for ported main speakers. This is what I did , and it worked out exactly right, both with my Quad 2805s (with a 4th order slope on the stats to have them least affected by the dynamic sub) and in an experiment with my Harbeth P3ESRs. This is, of course, with the main speakers playing full range without any high pass filtering.
Just by the spec sheet, as was the B&W suggestion. The result was 33 Hz for the Quad 2805s and 45 Hz for the P3ESRs. In short, as per REL theory, only filling in the very lowest frequencies.
In addtion, the sub's manual writes: 'If the specification of your speakers only quotes a –3dB frequency, multiply this by 0.6 for closed-box systems and by 0.7 for vented-box (reflex) systems to get a close enough approximation to the –6dB frequency.'
I'll just leave it at I disagree. But no harm in trying and seeing if that works best for you.
I could simply be expediency:
It might be much easier for a sub manufacturer to explain to a user how to add bass to his existing sound, when compared to telling him how to calculate a high pass in such a way that doesn't ruin things.
In other words, it may not be optimal, but it's probably easier for many to do reasonably right.
I considered this too, but then I thought how many factors would have to come together for this to work:
Just can’t imagine that it’s more likely for all these factors to miraculously combine successfully, than for a HPF one octave or more above the speaker’s F3 with the same slope as the sub’s LPF at the same frequency to integrate reasonably well.
- Manufacturer correctly specifies the F3
- 70% of F3 is the -6dB point
- Speaker roll-off closely resembles the filter slope used by the sub’s LPF
- Etc...
Oh, it may not actually lead to better outcomes.
But the decision tree is simpler:
"Hey my speakers sound like they always do, but now with too much bass / not enough bass / just right bass."
vs.
"Hey my speakers don't sound like they used to....and the bass is different, too..what to do?"
Since your main speakers already go pretty low, adding very small subs may not add that much. As for location, I discussed this with the engineers of my Antimode 8033 and their advice was to push the sub(s) well into the corner(s) of the room, for maximum corner reinforcement and shallowest dips. Peaks would be bad, but the Antimode would cure those.
Hi
The literature is abundant: Science-based peer reviewed, provable, repeatable, that multiple subs in most rooms provide smoother and more linear bass than one. This is beyond simple anecdote. A few "el cheapo subwoofers will provide more accurate and powerful bass than a single more expensive one. I am willing to go on a limb and advance that 4 cheap around $250, sealed subwoofers + an appropriate controller, say a mini DSP 2x4 @<=U$D 125.00 + A UMik at U$D100, for a grand total of $1500 cables included, shall provide better results, in quality, smoothness and linearity than a single sub with any DSP and do-dad you want to add to it at $2000 and over ... Since this is my mind experience, , I'll bring the price to $5000 for the single sub, I dare not say what a $10,000 single sub will do but physics (a branch of Science ) are against the lone sub whatever its price in most rooms the normal or even the well heeled audiophiles are likely to have. For the record a 20 x 15 X 10 meters room fall in the realm of "Small-Rooms Acoustics"... thus everyone (Save for the hidden castle of the King, he won't let us know ) on this board has a room that falls under the "Small Room Acoustics" realm.
Of course , truism-alert!!!, there is not free-lunch. This not automatic. You don't just drop the subs and Voila! linear bass! Nope . You read a lot, you learn, you learn to measure with REW and UMik, you fail, you learn more, you learn to interpret the results and you learn how to use the not so great interface and get to the results. The miniDSP 2 x 4 + UMik + REW combo is not the only way to get there but it is one of the cheapest IMO. I don't see how you can get to great bass without measurements... so REW (Free) and (at least) UMik $100 are a requirement. Now way around it
I'll try a formula: If Bsub is the budget for the greatest single subwoofer you can afford with the specs you dream of in your room then the price for each of the 3 lesser subs would be:
LesserSubPrice= (Bsub-225)/3
Example: you budgeted $3000 for the one sub with the great specs , rather go for 3 lesser subs @ $925 each ... Guaranteed better results
3 subs following Geddes are better than 2. 4 is the threshold of diminishing returns for Welti et Devantier. Geddes approach favors a quasi random positioning of the (at least 3) subs. Geddes almost advocates different sealed or passband subs.
Not exactly: he prefers 3. Rarely if ever suggests 4.