Yes corner loading something capable of going low is in my view a win win, easier to locate, potentially no need to EQ other than in my case avoiding the very strong room resonance at 34 Hz, which I actually might be able to remove by adjusting the X over. Whilst I'd love to avoid DSP, especially as I need to go from A>D then DSP then D>A I only do this with the subs and have spent a lot of time upgrading the 10x10 HD unit In use. I Dre 5 subs o without a control unit it wood be near impossible. I suspect if they ever produced a processor that had 12S in and all the DSP-digital adjustment, configuration etc, then 12S to DACs then to a preamp it would be nirvana. But they wont because I think I'd be one of the three customers interested !
Having said that the Storm EVO might be interesting but the costs would be £15k plus DACs so not cheap
My 18's tucked away (I'd move one to the opposing corner but cant in the current room as its a door way)
I am glad my wife is understanding of my hobby.
A single 18" woofer never hurt anyone.
If it's that difficult you can always try to "bling it up", apply some gold paint or real gold leaves if that helps.
I might go for copper or bronze, that could be fun.
I've also heard the same stories, I haven't A-B'd at home but really like the spec and databass really liked it. It's superb sonically for what I am looking for - Deep tight and effortless bass up to 30/40 Hz. On films I havent heard better for the subsonics at 18". I have experimented with rolling off later and taking the 12's out of the system, I preferred the 12's in place, possibly as they are more responsive, possible the alignment with the 18's is less good at say 60 Hz+ I'm still struggling to understand all the variable when assessing transient response BL^2/Re, MMs, inductance etc
These French guys made extensive testing on some big woofers and the Beyma 18LEX1600ND stands out against the BMS.
It can be interesting, since the Beyma is a lot cheaper.
http://unepassionaudiophile.fr/wp-c...comparatif-rapport-dessai-du-20-aout-2019.pdf
It can be interesting, since the Beyma is a lot cheaper.
http://unepassionaudiophile.fr/wp-c...comparatif-rapport-dessai-du-20-aout-2019.pdf
Interesting looks like it was ported ? Was the objective pure SPL at low distortion ?
Yes, vented. They created an "enclosure" on the floor and trimmed its volume with water. Then they mounted the hp on a steel baffle next to a pipe vent.
Crown XTI 4002 bridged amp to feed the hp and Audioprecision gear to take measures.
Basically distorsion levels both at high spl and lowish spl.
The goal was to provide "objective information both for audiophile and high SPL use"
Their final verdict is "The Beyma 18LEX1600Nd and the B&C Speakers 18TBW100 are by far the best of the lot"
Very nice measurements! This again shows what I detected with PA speakers for low/midrange - some of them show very high THD at LOW levels! I would estimate that's from effects like suspension creep. The 18TLW3000 shows best behaviour here, the Beyma does also good. Both have pretty high Qms btw.
For useing an 18" in a home audio system I would have a close look to these low SPL numbers - cause when you use them at 120dB your ear will already distort a lot anyway and it dosn't matter that much 😀
For live audio you will sit 30m away and don't play 88dB/1m ... it doesn't matter as much.
So you have a closed subwoofer with an f3 of 55Hz. You complain about not enough low frequencies but refuse to use filters (EQ).
Instead you want to built in a resonator which gives very little gain cause your volume is wrong for a fitting setup and will produce a lot of membrane movement at (very) low frequencies.
Of course you can do so, but it will be ... not optimal 😉
You have everything you need by hand - just do a fitting low shelf for your existing woofer to get your low frequencies. Group delay will follow to what you do with your filter. You could even "simulate" a reflex speaker if you really want that ...
You can add filters in your simulation programm - give it a try.
A perfectly working electronic/digital filter will always behave as predicted. A resonator has downsides, especially at lower frequencies as the tuning frequency.
When you need more maximum SPL at low frequencies - build a proper volume, do a deep tuning. But your plan does more harm as it helps.
I would love to try a range of 18" drivers at home in the cabs I built but its an expensive exercise, I am open minded which would sound better in my application, I suspect they would all be good. I do like the 19mm Xmax of the 18N862 if you are going down to 10Hz or less, I think in a prefect world you would have very light, responsive and efficient 12" or 15" drivers dealing with 40-80 Hz. Listening I do know most of the bass notes and bass transients we listen to/for are more in the 35-90 range
http://www.loudspeakerdatabase.com/Eminence/DELTA_PRO-18#8Ω
My answer is a no, no, no, to everything you say. I use boost DSP ( Post 37 ) for the sub-bass, progressively
from 80hz all the way to +12db at 20hz.
The result is very good, I have already said it. I want to play a bit with a BR, I have already explained the reason. In the Eminence specs this subwoofer is listed as N/A for sealed. Why with an EBP of 84 do they rule it out for sealed? Well, J.M.N from Eminence explained it to me, they created this short Xmax subwoofer and a 4-wire VC to achieve a lot of "punch", the range that guys like in clubs, and hold a lot of power. That does not mean that I cannot use the part of sub frequencies that interest me.
DSP corrects the drop, whether sealed or vented, and obviously, the reinforcement in the BR will be less. If something goes VERY wrong (boomy bass? well I don't think so, I bet), plugging a hole in the base will be very easy. By the way, your opinion about the location that I proposed about the tuning tube, what is it?
In post #59, you wrote "My expectation is to use the converted BR subwoofers without any DSP or EQ".
Your 28Hz Fb BR simulation only predicts 3-4dB gain over the sealed cabinet, the BR with -8 dB LF level would sound quite thin by comparison to what you have become used to without the LF EQ boost.
If you are set on no DSP or EQ, I'd suggest a higher Fb of around 36Hz so the low end does not drop off so much.
"Boomy bass" won't be a problem with your proposed BR alignment.
Over excursion and the resultant vent noise and added harmonic distortion when driven below Fb may be a problem if you don't use a HP (low cut) just below Fb.
A port exiting on the bottom of the cabinet is OK, though the floor and back walls effectively become part of the port length unless the cabinet is raised to roughly the port diameter, probably higher than you may want for appearance sake, especially if using an adequate port diameter to keep vent velocity in the <20 meters per second range.
I'd suggest using the rear corner location for the port.
You could use higher Fb (shorter port) and then lower the cabinet height to tune lower.
Have fun, and like chess, try to plan your moves ahead!
Art
Looks like both of those are better for ported as well, not sure if that influences things, I dont think I would have bought the Beyma with an MMs of 393g and the B&C is similar MMS to the BMS but only 12mm Xmax
Something like that?, the calculation will be quite complicated since the ends are at an angle.....
I didn't say that I won't use DSP, I just imagined that maybe it wouldn't be necessary, because there will be a lot more gain in BR, (6 db between the two cabinets + the room gain in the corners) but having DSP is an advantage that I can't ignore if with this I achieve a good result.
Here it says that for an 18 "speaker the port must have a minimum of 8 inches of diameter !!!
This is getting too complicated...
https://www.subwoofer-builder.com/port-flares.htm
By the way, I'll do "radio silence" for a few days, I'll be on vacation.
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Looks like both of those are better for ported as well, not sure if that influences things, I dont think I would have bought the Beyma with an MMs of 393g and the B&C is similar MMS to the BMS but only 12mm Xmax
I already use that metric even though a lot seem to disagree that this makes sense, their is also the 1w acceleration calc which shows a similar ranking with drivers
The 18N862 shows less (0.42) than both the Beyma and B&C (>0.6) so perhaps they might sound better, try this with 15's and yo can easily get to 0.8 or more. The Beyma has huge BL and although I feel nervous about an MMs nearing 0.5kg maybe this is the M5 of the car world ! Bloody heavy, but fast
For subs I prefer the horn design standard of choosing specs to load the entire BW, i.e. 20 - 80 Hz with a 20 Hz Fs driver = Qts' = 2*Fs/80 = 0.5 after factoring in (Rs).
(Qts') : (Qts) + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html
Think more about it and try stuff. You will get it. 🤓
Just don't get to loud - you don't have a long excursion driver. Choose a different driver for more SPL.
Just don't get to loud - you don't have a long excursion driver. Choose a different driver for more SPL.
Don't do it. Build a cab with enough volume for the driver so you gain at least 8dB of level around the tuning frequency (cause in real life it's always a little less).
You try a ported cabinet with nearly no gain and all the downsides ... my answer is a no, no, no 😉