Subwoofer costs/wattages, why the disparity?

kylarstern

Standard Member
Honestly, without a whiteboard and 5 hours, I can't explain what I meant by "rounded". 🤪
I was just trying to figure out where 100mm came from when when it was 38mm in either direction (76mm 2way xmax). And....I just googled "subwoofer diagram", and realize the rounded part I was referring to was the "dust cap".:facepalm:

I feel this picture is relevant now.:
1620321305206.png



Regarding the REW, you're saying I could use it w/o the calibrated mic to just play around and see where peaks/troughs would be? I'll probably buy the calibrated mic, and even if I don't use it, hook it up to a laptop and put it out whenever friends drop in...it'll look cool at least. :)

I have a new place and have just retrieved my kit from storage - I have missed it so much, lol - so now need to re-Audyssey and then do the additional REW measurements and EQing that I never managed in the old place!
How many of your own speakers have you built? What kind a set up do you have? What's your primary listening source? Movies/music?


Thanks again for all the detailed info. It honestly makes me appreciate the complexities of speaker design.
 

kylarstern

Standard Member
So this video was just posted regarding using a flat pack. I like this approach as I don't have the measure twice and cut once...i don't have to measure or cut at all!

Dual 18"s for less than 2k...

 

MemX

Well-known Member
Honestly, without a whiteboard and 5 hours, I can't explain what I meant by "rounded". 🤪
I was just trying to figure out where 100mm came from when when it was 38mm in either direction (76mm 2way xmax). And....I just googled "subwoofer diagram", and realize the rounded part I was referring to was the "dust cap".:facepalm:

I feel this picture is relevant now.:
View attachment 1507224


Regarding the REW, you're saying I could use it w/o the calibrated mic to just play around and see where peaks/troughs would be? I'll probably buy the calibrated mic, and even if I don't use it, hook it up to a laptop and put it out whenever friends drop in...it'll look cool at least. :)


How many of your own speakers have you built? What kind a set up do you have? What's your primary listening source? Movies/music?


Thanks again for all the detailed info. It honestly makes me appreciate the complexities of speaker design.

You should be able to find some flatpack options quite easily if you go with 18s, but if you go with ridiculous 24s :D then you might just need to go custom order, lol.

REW Room Sim looks like this:

REW Room Sim screengrab.png


You can see the speakers and 'head' on the left hand side, and then the response at the 'head' (listening position) is shown on by the peaks and troughs in the graph.

As you can see, the curve for that listening position is not very flat! And those troughs / nulls will be difficult to overcome.

It's that sort of situation that needs to be remedied by either moving the sub, moving the listening position, or by adding another sub in a good position to smooth the response.

You need to follow the links to download REW here:
REW room acoustics and audio device measurement and analysis

You might have to create an account at AVNirvana, but I think they must have lots of 'visited once for a download' accounts, lol.


I've only personally commissioned one set of speakers, a pair of 'Push Pull Slot Loaded' subs using 4x18" Stereo Integrity drivers. One of the other chaps on the forum built them, but I think he's left now! I'm not sure if my build broke him a bit :D lol. I tried to design it for a very 'clean' sound (hence the PPSL design that seems to cancel out even-order distortion) so to be good for music while also having a lot of displacement for movies.

I like them a lot! but I will admit that the sound threw me off a bit when I got them - they are so 'clean' that it felt like something was 'missing', it's weird to try to describe it. It could all be psychological of course :p but I am very pleased with them, either way :) even if I'm just running an Onkyo AVR and playing discs through a £100 blu ray player instead of some $$$$ thing, lol.

I'll find the link to it in a minute!

@mattkhan has done more speaker design work - it's a somewhat 'dark art' in terms of crossover design, designing for even output across an area, etc etc., so I've not tried it!

The DIYSG stuff linked to earlier is well rated, though, and is basically flat pack :)
 

MemX

Well-known Member
Here you go - this is my build/commission thread, with massive thanks to James because they are still going strong (and killing anyone trying to move them! haha):

The MemX DIY procrastination thread - 4 SI18s in 11 cubic feet?

Pic of one of the drivers is on page 2, then the build pics start around page 5 (if you have the same page settings as me, obviously, lol).

I need to go back and re-read it myself, so I can reacquaint myself with the miniDSP / EQ stuff!
 

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