Which 18'' driver should I pick for this br subwoofer?

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#3
Hi,
pick any of them, the first one (TLW3000) is likely the most advanced driver and likely most expensive one, has most power handling capability so can provide more output, with more cost. They all seem quite nice, the last one having least power handling so lowest max output capability in that sense, likely also cheapest cost. Differences might emerge when you drive it near the limits. If you cannot see which one of them works best for you from the datasheets they all likely work just fine, I bet they all sound just fine.

Forget passive crossovers for PA use, though, the components would cost a lot and as they heat up (with power) everything goes out of whack. You would need high pass filter for the sub (and mains), and those get really expensive. You'd also benefit limiter and ability to adjust to a room, which are things that all favor DSP.

You might get away with passive xo in home use, though. You could make the top box sealed for home reducing some audible issues related to ports (by sacrificing some max output capability). Also any of the sub drivers is likely fine, enough power handling, for home use.

I highly recommend DSP though, I suspect it will be similar hustle and cost as passive xo, but more flexible and handy and thus likely results better sound in the end.
 
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#4
Im not going the dsp route 🙂 .. i might consider a diy active crossover.. it’s going to be stationary.. I’m not really looking for max output but a kind of dry bass .. mix of listening bar where u can dance kind of vibe.. I heard the 18lw2400 is the driest of the lot.. I don’t really trust the source.. was hoping someone here could confirm that.. and a good crossover point.. I’m thinking 100hz maybe 120hz?
 
#5
Bass is dominated by the room modes, so at one end of dance floor the bass could be described dry, while few steps to middle it could be boomy. And then on a next song the kick is different frequency and now the situation could reverse 😉 so if you want dry bass check out what multisub system is all about, how to reduce effect of modes so that bass would be more even through out the audience. Or any other means to manage bass in a room. I would not associate "dry" to a driver brand and make and model, but room and positioning of the sources and the listener.

Also, if you want no DSP and dry bass I think they are conflicting requirements in my experience. Since we have to deal with acoustics, and physics in general, it's not good idea to have personal wants how to get a result, because that could be wrong and make end result wrong, as the want might be exactly opposite what one actually needs to get particular end result. Eventually only the end results matters, so it's better to relax on the wants if necessary, than sacrifice the end result just because. Or, just let the end result be whatever it ends up to be dry or wet, anything between.

I hope you get good end result with passive system, but I'm afraid you don't, so perhaps consider the active analog from the start, at least for the sub.Very least keep open mind: in case the passive solution doesn't work out you could revert to an active system afterwards. I don't know any details of your plan so perhaps it works out fine. Active system, and especially DSP gives higher probability to get good sound regardless of place.

100Hz xo isn't too bad passively in ideal case, but the sub likely has rising response and actual needed electrical low pass likely ends up below 100Hz, or needs additional filtering, to make 100Hz acoustic lowpass. You also need high pass filter for the sub, as reflex box doesn't limit excursion below box tuning it risks the driver. Although pro drivers are quite sturdy so they won't likely blow up on every dropped turntable needle, long term low frequency output would burn them, so high pass filter is kind of mandatory. This is much cheaper to do active than passive.

Wait for some other answers before counting on mine. Have fun with your project, it sure sounds fun time ahead!
 
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#7
Yes DSP crossover means the crossover is before power amplifier on line level signal, but, now you need one amplifier channel per driver. Same thing with any "active" crossover. "Passive" crossover would be after power amplifier, so you'd need just one amplifier (per speaker). This is high voltage and current so the crossover parts need to be quite specific and are affected by heat for example. There are pros and cons for both and it depends on application which one would be more suitable, cost and complexity is also something to consider besides how the actual audio is affected.

It's impossible to make a crossover before you build the system and then measure it. So, what you need to do is build the boxes, invest some time and effort to get at least some measurements of it, preferably do it properly by collecting enough data to make proper crossover. Today best is to use computer sound card and measurement microphone for that so that you can make proper dual channel measurements (the other channel works as timing reference) and then measure so called spinorama: in addition to the traditional on-axis frequency response many other axis are also measured to get more complete data of the speaker. These measurements are loaded into a VituixCAD, which is currently the best and free, crossover design tool. Based on the data, the crossover is then made. Next you'd implement the crossover and ideally measure the system again to confim the performance is like simulated to spot any errors.
 
#9
I see 🙂 so that one is solved for now.

Yeah you could keep the tops passive and focus on the sub. Crossover between sub and top is your main task to figure out how to do it. This is often the same process as "integration" of sub(s) into a system. Simplest process I can think of now is just to build the setup, the top with it's passive crossover, and the sub, and then for example borrow a MiniDSP setup from your friends, or any DSP system you could try the system on and tweak it into the situation. Then, after you have made it work you'd know what kind of filters you have there and make active crossover to replace the DSP.
 
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