Thank you for posting that again! While playing with slot loading, I had the thought, "that one guy told me about slot loading, but I couldn't model it right".....you are that "one guy" lol. Sorry, not the best memory.
My issue is what to do with the 2 18"s...Slot loading vertically, face to face, reduces their foot print. I can do that horizontally but that forces the distance from ear down a little and distance from the above source. In the near field, minute changes like this do make a difference, whether these specific changes are detrimental or not, I don't play that game, I just try and error towards SQ.
- you're a cheater
My issue is what to do with the 2 18"s...Slot loading vertically, face to face, reduces their foot print. I can do that horizontally but that forces the distance from ear down a little and distance from the above source. In the near field, minute changes like this do make a difference, whether these specific changes are detrimental or not, I don't play that game, I just try and error towards SQ.
Last edited:
Just like but with a vertical slot. It is Djk, if I recall, who experimented with different slot width ratios, including 1:2.
Here's the configuration I commonly come across showing 1:4 gaps are used too.
I haven't encountered any discussion about slot width vs diaphragm diameter before....or any ratio thereof...interesting...
I've always thought slot width is simply the width of the slot between the driver baffles...and that it's 1/4WL size is the upper end of usable response..
I just made it a front loaded horn with the initial CSA the height*width of the slot. length, the literal length of the slot, even though its not exact since a part of woofer is right at the mouth. To simulate pressure of anothger woofer firing at another, halve csa, for an estimation, I'd say.
Just like but with a vertical slot. It is Djk, if I recall, who experimented with different slot width ratios, including 1:2.
Here's the configuration I commonly come across showing 1:4 gaps are used too.
I am not sure if somebody already mentioned the Ripol:
RiPol Subwoofer – RStAudio.de
You should consider the Ripol sub. It is a step further.
increases directivity of direct energy? I can see that waves are focused like i thought they would. Can't go higher than 30hz but I see it at 30hz.
Thx for this summary of your experiences with different loudspeaker systems. It's interesting and useful for those who consider building 1 or more of these concepts.
As for the Meyer Ultra X-40... Diffraction horn revival
Attachments
3db is a lot it is the same as doubling the power input, not easy to get and shows the difficulty in getting SPL low down it takes a lot of volume displacement.
These are just comparisons the drivers were the ones you were comparing in your charts.
It's become quite difficult to know exactly what your goals are the posts have been moved a few times, even if they have ended up back at the same spot
My point was not to suggest that you seek 10Hz at 130dB but that 30Hz is still quite a high point to consider your lowest frequency of interest.
I think that with 30Hz F3 with a Q=0.7 slope in a sealed cabinet gives good low extension but allows higher spl's and more headroom.
SL's sub target was 20Hz and Q=0.5, that limits the SPL and headroom quite a lot more.
No suggestion was made that any driver would sound better or worse only that some drivers parameters make them more suitable for certain kinds of tasks. Maybe that has come through now.
30 Hz suffices for 95, probably 98% of all music ever recorded. In terms of impact, 30 Hz from an 18" or bigger Pro driver will trounce 20 Hz reproduced by 8 or 10" audiofoolish woofers. But as the saying goes: "You can't ever have enough (sub/infra) bass."
Last edited:
Also very true, quality is harder to achieve than quantity
Live sound is quite different in approach to home or studio audio. Even though the speakers and drivers can be interchanged sometimes there are differences which are due to constraints the other doesn't have to suffer.
The size of a box is important to a live sound company that has to ship them in standardised containers. In a home it does not really matter if it is 20" or 20.5".
In live sound the weight of a box is a consideration as someone will have to keep moving it. In a home mostly not an issue.
In live sound it has to be loud, the louder it is the less boxes you need the cheaper it is the less effort it is.
None of that really matters as much in a home or studio so those constraints are not there and cutting sub 30Hz is not as good a trade at home or in studio as it is on the road.
The down side to this can be seen in home produced music where it was mixed and mastered by small speakers with no low bass ability. Everything below 60Hz is a total mess because they could not hear it (Headphones can help but are not a complete solution).
Live sound is quite different in approach to home or studio audio. Even though the speakers and drivers can be interchanged sometimes there are differences which are due to constraints the other doesn't have to suffer.
The size of a box is important to a live sound company that has to ship them in standardised containers. In a home it does not really matter if it is 20" or 20.5".
In live sound the weight of a box is a consideration as someone will have to keep moving it. In a home mostly not an issue.
In live sound it has to be loud, the louder it is the less boxes you need the cheaper it is the less effort it is.
None of that really matters as much in a home or studio so those constraints are not there and cutting sub 30Hz is not as good a trade at home or in studio as it is on the road.
The down side to this can be seen in home produced music where it was mixed and mastered by small speakers with no low bass ability. Everything below 60Hz is a total mess because they could not hear it (Headphones can help but are not a complete solution).
- I see your point. Why didn't you just say that lol! Go deeper?
- I'm sorta doing that.
After seeing this you may want to say that I should just get rid of the 15"...but this can only be true if I can crossover low enough and thats not a guarantee. What woofer do you suggest btw? This is just the picture I could find, an example of what can be done, if you will...I remember playing with xover on the 15m and getting it so that it only touched something like 3mm of excursion at 115db....this might be modeled with just one 18..not that it makes a huge difference? I think qts suffered to .49?.....189l per 18.
Last edited:
I thought I did
I don't see the image it's gone somewhere..
I would use multiple sealed woofers, (between 2 and 4) spread around at the best measured locations anywhere between 12" and 18" depending on the space and budget available.
For myself I have bought 15" HF Reference Drivers as they go high enough to cross wherever I need and have enough Sd and Xmax to go much louder than anything else they will be used with and were available to me at a reasonable price. Not always the case in Australia. No refrigerator sized box or an amp to melt the house wiring needed either.
I really like the look of the B&C 18SW115 the motor on that driver is incredibly linear the klippel results are almost perfect. It models very similar to your TD18H+ (same Sd and xmax), the BMS 18nd driver also looks to be very good, but 18's are hard for most people to fit in multiples me included
Rss390hf
Another shout out from an armchair quarterback (no experience with it).
.707 sealed, vb 4.5ft3, f3 = 32hz.
200w, 108db at 14mm xmax at 32hz.
200w, 102db at 14mm xmax at 20hz.
I hadn't thought of it as a non sub, but i loved my magnum 15's run 750hz down (27hz tuned).
I don't know of an 18 sealed with f3 near 30hz, let alone call for sealed .707 less than 10ft.
B&c are pricy this side of the pond.
Norman
Another shout out from an armchair quarterback (no experience with it).
.707 sealed, vb 4.5ft3, f3 = 32hz.
200w, 108db at 14mm xmax at 32hz.
200w, 102db at 14mm xmax at 20hz.
I hadn't thought of it as a non sub, but i loved my magnum 15's run 750hz down (27hz tuned).
I don't know of an 18 sealed with f3 near 30hz, let alone call for sealed .707 less than 10ft.
B&c are pricy this side of the pond.
Norman