The toroid is the best shape as far as I know; the inductance value is higher for the same amount of coil wire using any other type of core. I did EMI and RFI suppression for the Telecoms as part of my career; the best designed filters almost always used a toroid core. The DC resistance is VERY low here; a huge advantage because I am doing this passive. Of course; active crossovers are better; maybe next year???
An air core won't saturate but a toroid can. Your advantage here is the low resistance. You mention one reason here.
Which indicates the cores involvement, and is part of the consideration toward saturation. There is a hysteresis plot available.
Ferrites also tend to be lossy at higher frequencies. They can present resistance to RF without getting involved with lower frequencies.
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Yes but 5.6 mH air core would be a very high DCR compared to any solid core. This particular inductor is rated for 700 WRMS with a DCR of 0.078 Ohms.
Other coils of that inductance I found were 15 or 16 AWG and they all had a DCR of 0.25 to more than 0.26 Ohms and rated for 400 to 500 WRMS. These had more common Ferrite or steel cores.
a 12 AWG flat foil air core inductor in this inductance has a DCR of at least 0.4 Ohms.
a 15 AWG air core inductor in this same value has a DCR of 0.63 Ohms.
The wire gauge and DCR are the most important here of course. But even at power line frequencies and audio frequencies the toroid shape core has many advantages as I understand it. It takes less coil wire turns with a toroid coil to reach the same inductance of other cored types. I posted two links that discuss this; that includes power line and audio frequencies; not just RF.
I'm never going to reach even 400 Watts of course but this woofer does have a 3 inch VC is rated for 200 WRMS and the LP X/O is below 200 Hz so I need the best inductor here. Maybe next year I can go all active for X/O. The Crown again is rated for 330 to 450 WRMS at 8/4 Ohm. The SB29 is 6 Ohms. It's possible I could have 200 Watt peaks.
I'm still playing around and tweaking; I may need to put the Satori MW 16 "woofer" with a 2nd order HP X/O to reduce IM even more. A 220 Hz 1st order HP will obviously still let plenty of lower bass reach it. I played some recordings with a lot of bass content from 40 Hz and up the other day. I watched the cone movement of the MW16; moving from 150 Hz to 220 Hz seems small and insignificant (especially 1st order) but the excursion was visibly and obviously much less at the 220 Hz HP using the exact same test recording at the exact same volume control setting.
The mad scientist mode I call it; tweak and experiment to my hearts content. Keeps me busy and happy and exercises my brain and gives me something to do constructive. I'm mid 60's, retired but rarely bored.
My logic and thinking process spelled out once again...
Cheers!
Other coils of that inductance I found were 15 or 16 AWG and they all had a DCR of 0.25 to more than 0.26 Ohms and rated for 400 to 500 WRMS. These had more common Ferrite or steel cores.
a 12 AWG flat foil air core inductor in this inductance has a DCR of at least 0.4 Ohms.
a 15 AWG air core inductor in this same value has a DCR of 0.63 Ohms.
The wire gauge and DCR are the most important here of course. But even at power line frequencies and audio frequencies the toroid shape core has many advantages as I understand it. It takes less coil wire turns with a toroid coil to reach the same inductance of other cored types. I posted two links that discuss this; that includes power line and audio frequencies; not just RF.
I'm never going to reach even 400 Watts of course but this woofer does have a 3 inch VC is rated for 200 WRMS and the LP X/O is below 200 Hz so I need the best inductor here. Maybe next year I can go all active for X/O. The Crown again is rated for 330 to 450 WRMS at 8/4 Ohm. The SB29 is 6 Ohms. It's possible I could have 200 Watt peaks.
I'm still playing around and tweaking; I may need to put the Satori MW 16 "woofer" with a 2nd order HP X/O to reduce IM even more. A 220 Hz 1st order HP will obviously still let plenty of lower bass reach it. I played some recordings with a lot of bass content from 40 Hz and up the other day. I watched the cone movement of the MW16; moving from 150 Hz to 220 Hz seems small and insignificant (especially 1st order) but the excursion was visibly and obviously much less at the 220 Hz HP using the exact same test recording at the exact same volume control setting.
The mad scientist mode I call it; tweak and experiment to my hearts content. Keeps me busy and happy and exercises my brain and gives me something to do constructive. I'm mid 60's, retired but rarely bored.
My logic and thinking process spelled out once again...
Cheers!
GENERAL DESCRIPTION
C-Coil is wound around a sandwich core, and it has extremely low resistance and can shift a large amount of power without getting over heated.
The core is formed like a donut with a round cross section, and it is wound from one long piece of laminated steel tape.
The surface of the core is epoxy coated to secure against short circuit even at a very high load.
We have tested the inductor with a carrying load of 1000 Watt, and it lasted and stood up well.
It can stand upto 700 Watt per 48 hrs in one go.
The C-Coil is designed for Bass, Sub-Woofer and Amplifiers, in different core and wire sizes.
Please note!
The C-Coil cannot be measured using a universal LC meter. Due to the characteristics of the core and winding method, it is important to use a professional RLC meter. We measure all C-Coils before shipping them using a professional RCL meter at AC 1 V 1 kHz.
The above from a description by Jantzen; tested at 1000 Watts; held up to 700 Watts for 48 hours continuous!
They specifically say these are only designed for sub woofers and woofers and not recommended for any crossover above 1200 Hz.
C-Coil is wound around a sandwich core, and it has extremely low resistance and can shift a large amount of power without getting over heated.
The core is formed like a donut with a round cross section, and it is wound from one long piece of laminated steel tape.
The surface of the core is epoxy coated to secure against short circuit even at a very high load.
We have tested the inductor with a carrying load of 1000 Watt, and it lasted and stood up well.
It can stand upto 700 Watt per 48 hrs in one go.
The C-Coil is designed for Bass, Sub-Woofer and Amplifiers, in different core and wire sizes.
Please note!
The C-Coil cannot be measured using a universal LC meter. Due to the characteristics of the core and winding method, it is important to use a professional RLC meter. We measure all C-Coils before shipping them using a professional RCL meter at AC 1 V 1 kHz.
The above from a description by Jantzen; tested at 1000 Watts; held up to 700 Watts for 48 hours continuous!
They specifically say these are only designed for sub woofers and woofers and not recommended for any crossover above 1200 Hz.
I just remembered. The Isobaric sub woofer I did back in the 1990's had two 12 inch Eminence dual coil/ 4 Ohms each; all in parallel; I had what was then a high powered Yamaha power amp that could deliver 500 Watts into 1 Ohm. Just as an experiment; I wound my own air coil inductors. I had access to a huge spool of surplus 13 AWG magnet type wire for free so why not! I ended up at 11 mH; the inner diameter was about 3 inches; the outer diameter was about 6 inches. HUGE for sure; highly UNUSUAL for sure! The added DCR helped here because the Qt of these sub woofers was quite low. These never lacked for anything; deep and accurate bass down to 16 Hz; very fast attack, etc. so the added DCR didn't hurt me much here at all.
Damn... very rare Fs today. The best I saw are the expensive hifi brands as ScanSpeak or SB Acoustic... which are expensive when the Fs is lovering and the Sd is increasing : look at the proce of the 15" SB Acoustic made...uh !
I look at 15" from Faital that have 35 hz Fs, the 11" paper from Eton looks promising as well and a little less expensive than the Wop from SB Acoustic... 35 hz, at least 40 hz should do well for most musics... with a low slope (sealed?) how is the room gain around that frequencies ? how much -F6 & -F10 are gd enough for 30 hz targett ? (I believe the big Sd of bigger driver is adding a more bass feeling even if they hit only higher in frequencies..as far as the relative spl level in highers frequencies mid + tweet are lower ! Correct ?
I look at 15" from Faital that have 35 hz Fs, the 11" paper from Eton looks promising as well and a little less expensive than the Wop from SB Acoustic... 35 hz, at least 40 hz should do well for most musics... with a low slope (sealed?) how is the room gain around that frequencies ? how much -F6 & -F10 are gd enough for 30 hz targett ? (I believe the big Sd of bigger driver is adding a more bass feeling even if they hit only higher in frequencies..as far as the relative spl level in highers frequencies mid + tweet are lower ! Correct ?
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They don't make these anymore of course. Paper cone; foam surround. Only rated for 80 Watts RMS but I know I hit them with 250 Watt peaks (all 4 VC in parallel that is) and they NEVER strained or distorted!!!
Eminence mostly make pro drivers; they did some home HiFi drivers and car drivers years, DECADES ago.
Eminence mostly make pro drivers; they did some home HiFi drivers and car drivers years, DECADES ago.
Now hitting the MW16 with lower bass; MUST use a 2nd order high pass; I know have about 180 uF with 3.6 mH. If I use the Q calculator and assume 4 Ohms, this gives me 198 Hz with a Q of 0.894. So, about halfway between Butterworth and Chebychev (+1). That means the "knee" is probably -3 dB somewhere between 225 and 250 Hz. BW says -3 dB at calculated f0 and Chevy' says 0 dB at f0. This means the 200 Hz is probably 1 dB down???
NO, SORRY, I got that bass ackwards. I was looking at the high pass graph and had a brain fart! Maybe -1 dB at about 200 Hz; maybe - 3 dB at about 160 Hz??? If the Q is almost 0.9; that should mean about 14 dB down at 80 Hz??? Here is where measuring the impedance would be REAL HANDY! Well, listening shows MUCH improvement in lower IM; the cone is moving WAY less here; regardless of the TRUE Q or f3, etc.
This could also mean - 26 dB at 40 Hz??? GOT TO GET THIS MEASUREMENT SYSTEM GOING SOON for sure!!!
I meant low pass graph above also; too many distractions!
Howard Johnson and Gravity "Testimony" CD. He is a tuba player and has a tuba and brass ensemble with many other instruments as well. Hard hitting deeper bass; modern acoustic jazz. Great fidelity; one of my many references...
I meant low pass graph above also; too many distractions!
Howard Johnson and Gravity "Testimony" CD. He is a tuba player and has a tuba and brass ensemble with many other instruments as well. Hard hitting deeper bass; modern acoustic jazz. Great fidelity; one of my many references...
you meant you wneed the Mw16p measurment ? It's 4 ohms where you cut as you pointed out : www.audioexcite.com >> SB Acoustics “Satori” MW16P-4
Maybe Audioexcite has measured your SB bass unit too.
Or do you mean in box ?
Maybe Audioexcite has measured your SB bass unit too.
Or do you mean in box ?
Well, it is the MW16P-4 in 15 liters closed box but on the new Crown amp so if I have a Q about 0.9 and the -20 dB point is above 40 to 50 Hz (custom 2nd order high pass); then it works OK here now. 1st order with heavy bass recording just has WAY too much excursion and IM distortion. Light jazz and Baroque; no problems.
I have seen the tests and measurements you show above. BUT; what is my EXACT f3??? f10????, f20????
I have seen the tests and measurements you show above. BUT; what is my EXACT f3??? f10????, f20????
More thoughts; the Satori 6 inch is having issues; what if I keep the SB29 for under 200 Hz ONLY. Get the 7 1/2 Satori either 4 Ohm or 8 Ohm. One suggestion was that the 4 Ohm would actually work in 15 liters (closed). This solves some issues for me. I don't care about how many drivers I have or what the X/O's might need to be. I want MUSIC! I think the SB29 IS hard to beat BELOW 200 Hz; If I used a 7 1/2 Satori in 15 liters to cover 200 to 600 Hz; this actually might make the most sense!??