Carbon Fiber 4-way 1st ORDER (bang for the buck)
The weekend was productive Fellaz! I have revamped the system, It was slightly inferior, and I have made NEW MODELS
The next five pages of my posts in this thread will be OUTDATED. THIS VERSION IS NEWEST.
!!***CHECK THIS LINK FOR GRAPHS-VISUALS FIRST***!!
This idea has spawned an 3-way OFFSPRING, which also does it, with a COST, COMPLEXITY, and SIZE CUT by a FACTOR OF 2.
I have mapped all the drivers seperately, and then have combined them into a TRUE 1st order electrical 4-way response graph.
The reasons behind this is that I realised the crossover points between the drivers must be -6db to have a flat response, therefore I have made assymetric crossovers to make sure Im as flat as possible.
The tweeter is already modelled with the series LCR notch in parrallel to the driver, but I havent added the effect of the Zobel impedence equalization networks which are in parallel to the cone drivers.
Thier job is to make sure that the higher frequency zones after the low-pass points to the cone drivers are rolling off at least as intended, if not quicker (meaning 9/db octave instead of 6db/octave). This will even out the bumped kinks you see on the red midwoofer graph, and the black midrange graph past thier low pass points.
Here are the crossovers:
1). 1" TWEETER
39$ SB26CDC-4 3.4 OHM
SB Acoustics :: SB26CDC-C000-4
1st order high pass CROSSOVER VALUES (7200hz -0, 5400hz -3db, -3800hz -6db)
C1 = 8.66 uF
5.5$ KZK WHITE LINE MKP CAPACITOR (WILL USE 8.2uF)
0.5$ KZK K78-34 BYPASS CAPACITOR (WILL USE 0.02uf)
SERIES NOTCH FILTER PARALLEL TO TWEETER (inductor resistance value has been subtracted from resistor value)
C = 33.93 uF
L = 1.57 mH (0.375 OHM)
Rc = 5.69 Ohms (INDUCTOR RESISTANCE INCLUDED)
2). 3" MIDRANGE
39$ RF-30QY-PRO 7.4 OHM
GHXAMP 3 Inch Midrange Speakers 8ohm 30W Neodymium 92DB Mediant Loudspeaker For Car Audio Upgrade 3 way speakers 1PC -in Combination Speakers from Consumer Electronics on Aliexpress.com | Alibaba Group
1st order high/low pass CROSSOVER VALUES: (450hz -6db, 675hz -3db, 900hz -0db / 1800hz -0db, 2700hz -3db, 3600hz -6db)
C1 = 33.65 uF
L1 = 0.44 mH
13$ KZK WHITE LINE MKP CAPACITOR (WILL USE 33uF)
0.5$ KZK K78-34 BYPASS CAPACITOR (WILL USE 0.02uF)
8$ VAJD AUDIO 0,19 Ohm 1,6 mm AIRCORE COPPER INDUCTOR (WILL USE 0,44 mH)
INDEPENDENCE EQUALIZATION ZOBEL CIRCUIT:
C = 11.8 uF
Rc = 9.25 Ohms
3). 6" MIDWOOFER
44$ STX 180.8 FCX v2 6.2OHM
W.18.180.8.FCX_v2 - Nagłośnienie STX
1st order low pass CROSSOVER VALUES: (337hz -0db, 450hz -3db, -675hz -6db)
L1 = 2.19 mH
16$ Z52-2,2/1,5 TOROIDAL IRON POWDER INDUCTOR 0,11 ohm (WILL USE 2.2mH)
INDEPENDENCE EQUALIZATION ZOBEL CIRCUIT:
C = 4.05 uF
Rc = 8.75 Ohms
4). 10" WOOFER
82$ STX W.27.500.8 FCX 5.9OHM
W.27.500.8.FCX - Nagłośnienie STX
1st order low pass CROSSOVER VALUES: (66hz -0db, 100hz -3db, -133hz -6db)
L1 = 9.39 mH
20$ Z52-9,1/1,5 TOROIDAL IRON POWDER INDUCTOR 0,22 ohm (WILL USE 9.1mH)
INDEPENDENCE EQUALIZATION ZOBEL CIRCUIT:
C = 25.19 uF
Rc = 7.38 Ohms
(COSTS: tweeter setup- 90$ / PAIR CROSSED, midrange setup - 121$ / PAIR CROSSED, midwoofer setup - 120$ / PAIR CROSSED, woofer setup - 204$ / PAIR CROSSED)
TOTAL: 535$ + zobels, using JANTZEN SUPERES.
If I wont have enought money, I will build cabinets but I'll leave the woofers out for some time. I'll loose only the lowest octave.
Here are the calculations for the 8 ohm units
AND THE CABINETS Ellipticor-3
Can you guy tell me why my thread is dying fast?
Did I make the post complicated??
Here's my take:
You have flooded this thread with too much.
You are building a 4 way and the woofers are only 8"? Can't say I've seen that, nor understand. Loosely, if you are going 4 way it's because the woofer is too big and the tweeter too small to make it a 3 way.
You are attempting a first order 4 way xo. Can't say I've seen that before either. They are hard enough to get right on a 2 way let alone a 3 way or 4.
How much background do you have in building and what is it that has brought you thus far? I think people need the questions to be asked more slowly and have you understand that you seem to be approaching this differently than others. That said, I'll step aside and see what response you get. You have had 200 views and 1 response thus far.
There are a few good discussion threads on why 1st order crossovers seldom produce good sound, especially with metal cones which have nasty cone break-up. Experts like Troels Gravensen use 3rd order ckt on aluminum dome tweeter and 4th order ckt on aluminum cone midbass (Troels SBAcoustics 61-NAC design).
A few plastic cone drivers (like 6.5" SB17MFC35-4) sound excellent with 2nd order circuits, and would be good candidates for 1st order circuits over a more limited bandwidth.
suggestion: use a simulator like Xsim or Vituix which use SPL+FRD+ZMA data files to compare paper, plastic, and aluminum cone drivers before you purchase parts. Square wave, step and impulse response, polar response, ... help grading.
Troels admits that his Ellipticor-3 requires selected drivers with minimal cone break-up and a slanted baffle cabinet in order to use simple 1st order passive electrical crossovers, and that the resulting acoustic slopes are not 1st order.
Troels: "There are very few true 1st order filter speakers in this world. Some may claim they do 1st order filters, but it usually comes with a grain of salt. The filter may be 1st order on the electrical side, but even so, the roll-off can be 2nd, 3rd or even 4th order from very simple filters - due to the drivers' inherent roll-off. And it all depends, because how far beyond the point of crossover must a driver go before we can call it a true 1st order filter? There are no rules for this, not even any general practice. My best bid on this issue is 2 octaves above and below point of crossover. Here the 18WE driver follows 1st order roll-off up to around 6 kHz, then a dip around 8-9 kHz and it stops around 15 kHz but never exceeds target profile. The tweeter is pretty much 1st order all the way from 15 kHz down to 800 Hz, where is starts rolling off 2nd order. "
Too much information. Why go with anodized drivers from aliexpress when for similar money you can get much better ones from true manufacturers? SB Acoustics`s ceramic line is not that far. And...looking at your post, I doubt you`d be successfull - you have to be massively lucky to get a 1st order crossover with a 1st order electrical. Indeed, most have more components than 3rd order.
Here's a curveball: why not do an active crossover? 1st-order XOs can be done with op-amps and low-cost parts. Sure, you'll need to do something about amplification, but IMO 3-way should be ample if you're not going above 8" in the bass.
Thanks for your responses guys!
1). I will be using double 8" woofers, with a total of 432 cm2 (around 13" worth of bass). What I win in this situation is: A). Transient response is better on smaller drivers, much less moving mass and therefore more detail. B). Less beaming on shallow slope crossover, allowing a higher crossover point C). Lower cost, especially on shipping.
2). I have settled for a 1st order crossover because Troels said you cant go wrong with phase, and I already have DIY experience in 12 / 24 db octave 3 ways, so setting a challenge for myself, in some terms.
3). In Troels quote Linesource posted about electrical 1st order having 1st order acoustic slopes, I have modelled my drivers acoustically flat (+-1db) not merely 2, but 3 octaves, or 18db to resonance peaks. That is more than his minimums.
Only the tweeter has an LCR curcuit, so its low end will surely be 2nd or 3rd order acoustically towards its resonance of 700hz, so I get additional power handling on the tweeter on a 1st order electrical.
4). The SB Drivers I have chosen have been thoroughly tested, and are perfect value in my book. As for the anodized chinese drivers i mentioned, those are flagship units in Chinese terms.
Yes, SB SS and SEAS may be more proven, but at least 2x the cost, and If i were to upgrade, i would do revelators or satoris, which are 4x the cost.
Being metal, they truly are the usual suspects for cone breakup, but as I said I'm rolling of 3 octaves below resonance.
I'm winning in detail, and bass punch, as we know ceramic cones offer more detail until you reach nasty breakups.
5). I would love to know more about abstracts idea of an active crossover. How can I use op-amps and low-cost parts? Tell me about this, really interesting. The goal here has cost efficiency, so this has my attention. I'm not saying I chose the best drivers, but for 5 units / 200$, show me better.
6). I have a real question guys. I understand I can convert-modify my 1st order electrical low-pass inductors on the midrange, midwoofer, and woofer to LCR circuits. I understand the woofer will swallow alot of capacitor, but this is more realistic on midrange and midwoofer. I simply stick to my inductor values and manipulate caps and resistors to achieve a notch filter if I get audible breakups on my setup without the LCRs.
In this case, the Zobel networks stay in place in any scenario, correct? Or im converting the inductors to full LCR, do the zobels go?
For additional info, this will be powered by an es9038pro DAC (350$), EAR 834 tube pre-amp clone (80$), and a dartzeel nhb-108 clone (600$).
Please dont hate, pirates have been the name of the game before our games)
|All times are GMT. The time now is 09:25 AM.|
Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio