Ideas for a kick-ass 8" monitor

Go on the first page and look at the distortion measurements.
That happened.

 

I built a single one of these. Mono FTW.

I've been distracted by other projects, speaker and otherwise.

 

distort where? didn't find anywhere..

 

lol, it's in the pdf, that pic shows "spl and distortion", still don't know what does that mean, are those diagonal lines = distortion?

 

Yep. The above lines are the FR at that volume level and the lines below are the THD at that volume level. The two major german magazines seem to use these plots. While I like that they measure distortion at multiple volume levels, I don't like that their plots are limited to 50db minimum. For 90db that is 1% distortion, which is already way above audible limits. I also dislike that the plots end at 5kHz. This is a limitation with the THD plots for sweeps that end at 20kHz. I would like to see distortion plots to 10kHz, so that the 2nd order distortion at that frequency is at 20kHz. D4 would be at 40kHz. FYI, the Lansche plasma tweeter measured with similar amounts of distortion as the Kii Three in the bass, but in the treble.

Another thing some people don't seem to get is that measuring distortion at 100db+ makes a lot of sense. Let's think about it. An example:

• You're listening to 'Dire Straits - Brothers In Arms'
• 'Ride Across The River' comes up. This is a dynamic song (DR17). You crank up the volume a little more.
• You're now sitting at around 85db(A) at the louder parts. This isn't super loud.
• BUT: The dynamic peaks are much louder. I was curious about this myself, so I put a microphone in my ear and used the REW SPL Meter to find out how loud the peak was. Pic is attached.
• I got a peak reading of 108.4db, but I don't think that this was in the bass. Bass peaks were about 100-105db. I reset the meter multiple times and I always got peak readings of 100-105db+ within seconds and this isn't a measurement artifact. A lot of the dynamic peaks were about 105db.
• To make things worse: Some of the bass peaks in this track have information that goes to 32Hz before it starts to drop off. Holy shit.

We could argue all day about how loud the peaks actually were. I have my doubts if they really were 105db+, but I think it's safe to assume that they were about 100db. This also depends on how the SPL Meter works.

We can assume that at a comfortable listening level we get 100db+ bass peaks that reach down to 30Hz with Ride Across The River.

The UERM fails this "bass test". So does the HD600 and HD800S. Depending on your definition, the HD800 either fails or barely passes. The distortion is audible, but doesn't make it a slow muddy mess. I assume this is because a lot of the distortion is low in level and 3rd order. I seem to prefer 3rd order distortion in the bass. 2nd and 3rd order harmonic distortion seem to be about equally loud below 100Hz with the HD800.
Most speakers fail this bass test. I think it's safe to assume that the DSPed Kii Audio Three would get rekt.

(I actually did this after I was at High End this year. I saw an amplifier that was sitting at around 1-5 W average, but short dynamic peaks brought it to 200-300W. It wasn't too loud and the speakers (Giya G1) weren't terribly inefficient either (specced at 91db). 20db louder is 100 times the power. That track probably had more than 20db dynamic range, more than 'Ride Across The River'.)

 

For clean 100dB at 30Hz you're looking at huge subs and specially treated rooms. And by specially I mean purpose built. Our anechoic chamber doesn't maintain it's anechoic-ness at these frequencies because of the large wavelength.

Good thing people are pretty crap at hearing bass THD mostly due to the fact the that sound at these frequencies is more felt than heard. Also it's usually a given that bass won't be too clean, so there's very little in terms of reference.

 

@Serious is there any really low distortion transducers?

 

For subbass - hardly. Think - big sealed boxes and many high diameter drivers to achieve less excursion for the same SPL's and extension. Usually THD isn't the first priority for subbass. Extension and getting rid of in-room nulls is more important.

 

30hz? ninja plzzz....i got high spl easily down to 15hz no sweat. ya catz nowadays..

 

ummm...i swore back in i believe 70's were a ev 30w... 30'' sub made by EV for some home/studio/theater speakers but, only had input of 30w for that behemoth and were very rarely manufactured but, easily 100db+ sensitive with very low distortion well below 30hz easily. got down to 15hz easy on it's own with very little to no movement.. jbl made lot of low distortion transducers for sub duty but, what do you expect from some one designing speakers for over 60yrs in all markets and branched off from an even more experience speaker maker known as altec lansing which is another 20 or so years on top of that...

RCA,Western Electric, EV, Altec Lansing and even nowadays, JBL were tops when comes to real theatre sound. the jbl 2245h was first known theatre/home 18'' to hit 20hz at 100db with very little to no distortion and very exceptional 2nd/3rd harmonic distortion...even lot of modern 18's still have hard time doing that. the 2245h was capped at 115db@20hz continuous on it's own before damage and that's in it's typical 4645 box it was measured...so can imagine full size theaters using 8 of these at once with 8 jbl 4648 dual 15's....insane response aww yea.. i only got 4 4648's and 1 4645 myself in house so...i'm getting there slowly in a way lol...

 

I'd like to hear/feel a rotary woofer one of these days.

 

same. they're interesting design. if i ever saw one locally i probably be interested in trying one.i'll just use the attics large closet space to install one in if i ever had one since they're very simple to install.

EDIT: nevermind....looked at price and it being 12k just for the frinkin blade motor alone and over 25k for everything including installation....i think i'll pass....be way cheaper just adding more subs in the area and still get good results.. i feel though i produce very adequate spl down to 15hz. with very tiny input power i shake the entire foundation with all the bass bins/subs hooked up with very little movement....kinda pisses off my g/f a bit though since it shakes everything like a mini earth quake but, she still loves me and supports my audio habit all the way lol...

 

Yep, the one you can buy is way too expensive. One could try DIYing one, should be pretty cheap.
True DC fan performance limited by electronic devices and your windows and walls!

 

Trying to DIY a powerful fan with adjustable-pitch blades seems like it would be a prohibitively expensive undertaking.

 

What do you think about the Seas Exotic combo W8 + T35 ?
Expensive, but are they worth it ?

 

I believe the result will depend on other factors rather than just the drivers. What are the main design goals of your speaker?

 

Resolution

I got a real bug in me for Accutons, but man, the price.
I've read the Accuton ceramic is hard to sit in between crossovers, too. Some day I will do 3 way, if I'm rich
Just sniffin' the alternatives.

Also it needs to play with my SET at first.
3 W and 8 ohms.