What software is used to check room gain?
I was an stupid thinking that can use so big driver in so small room. Sorry
I was an stupid thinking that can use so big driver in so small room. Sorry
No problem using a big driver in fact it helps keep excursion low which is good. The thing is that you need to account for it when deciding on a design. You will get better performance than a simple simulation would indicate. In ideal situations it will be 12dB/8va (exact inverse of the sealed enclosure roll off) beginning at (IIRC) the frequency where 1/2 the wavelength equals the longest dimension of your room. This is of course just a rule of thumb because a real room will have somewhat less gain due to air leaks and such but it gives you a feel.
So if your room gain is calculated to start at 40Hz and your fs on a sealed sub is also 40Hz then the actual response should be very close to flat all the way down to where you run out of excursion.
Do a search for online wavelength calculators and put in half the longest dimension of your room and see what you get. That should give you a pretty good idea.
P.S. this is why subs that knock your socks off in a car are next to useless in your living room.
So if your room gain is calculated to start at 40Hz and your fs on a sealed sub is also 40Hz then the actual response should be very close to flat all the way down to where you run out of excursion.
Do a search for online wavelength calculators and put in half the longest dimension of your room and see what you get. That should give you a pretty good idea.
P.S. this is why subs that knock your socks off in a car are next to useless in your living room.
Actually I think it would be many people's dream system.
And not just mono, as that can create its own issues like localising the speaker position based on subtle distortion or high frequency output.
Stereo 18 mmmm... 🥰
A pair of 10-12" drivers would provide plenty of bass, but then it's tricky to find a nice PA style accordion surround, combined with parameters for deep bass like a large Vas value. The 15+ drivers have definite advantages.
I've been looking at a few brands aimed at the musical instrument market like Eminence and Celestion, as they have lower power offerings, and options with low cone mass, which look like they would work well with tube-style amps and/or Linkwitz transform EQ adjustment.
Hoping someone else will jump in with better details as I'm not 100% certain on the process... but I believe you want REW (free measurement software for Windows, linux, and Mac; there is probably software available for smartphones, I'm just not familiar with them), and ideally a calibrated measurement microphone. In this case I think any random microphone (including a laptop with one built-in) will be fine, because we only need a relative measurement, not absolute.
Then I think the process goes like this:
#1 Build a small sealed sub with any junk driver. Performance is irrelevant as long as it has any measurable output down as low as needed. I'm pretty sure it needs to be sealed, not ported, but I can't remember the technical reasons why.
#2 Measure it outside (on flat ground, far from any buildings)
#3 Measure it in the room
#4 Compare or subtract the first measurement from the second. The difference is the room gain.
Last edited:
Searching some SOME EMC8000 mic to purchase, i have a UMC202HD that can use to connect it and to do some measurements!
No such thing, just a point of diminishing returns since we ideally want a very high SQ performing system which requires a high efficiency to keep thermal power requirements well below any audible distortion.
Huge?! 344/2/5 = ~34.4 Hz room gain begins in theory, rising at a max of 12 dB/octave if the room is a concrete basement or similar = +12 dB max/~17.2 Hz with 7-9 dB a common rule-of-thumb, so in short, best to design based on little/no room gain to ensure sufficient high SQ dynamic headroom.
As just about always, many clever suggestions... but before anybody knows what the problem is.
What kind of music - or home theatre??? What kind of room? What kind of other speakers and audio gear? Spousal factors? Carpentry skills? What past benchmark is OP starting from? Money?
Waste of time "answering" when nobody knows what is the question.
What kind of music - or home theatre??? What kind of room? What kind of other speakers and audio gear? Spousal factors? Carpentry skills? What past benchmark is OP starting from? Money?
Waste of time "answering" when nobody knows what is the question.
You see, it's not that everyone else here doesn't understand that these are crucial questions; it's just that we are treating OP like an adult who knows what they are asking for and why. That may not turn out to be true, but number one, that's not my problem and I prefer to 'assume up', and number two: trying to explain that is far less effective than actually helping, and letting them work it out for themselves.
Trying to get all possible context out of new posters before attempting to answer the quite clear and specific question they asked is not helpful IMO. It just comes across as intellectual snobbery; like you could answer the question, you just aren't willing to, unless you approve of the rest of their life choices.
This person asked "goal is max level down to 20hz or lower, box size no issue, here are some available drivers, how loud can I get?", which is not an unanswerable question. Again, this is different than the all-too-common "what is the best subwoofer driver?" type question, which is missing any criteria by which to answer the question - in a "how long is a piece of string?" way. Whether they should have been asking a different question in the first place (and as you can see that is becoming clear simply by exploring the answers to the question they asked), is, well... a different question.
Last edited: