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Discussion in 'Amps and Cabs [BG]' started by Chef, Sep 25, 2012.
sorry to hear Mike,
be well get well.
This morning I received a very good question about using the 4-ohm Thunderchild 112 as an extension cab. I assume we're talking about paralleling it with an 8-ohm speaker in a combo amp, and that the combo amp has a 4-ohm-capable head.
Instinctively you'd think the answer would be no, but the question arose because the TC112 is a "high 4 ohms", and the owner measured its DC resistance with a multimeter and came up with about 4.4 ohms, which is not too far off from the DC resistance of some "8 ohm" woofers.
Technically the TC112 is closer to being a 5-ohm load, and I could probably get away with claiming 6 ohms, but I claim 4 ohms because people are more used to cabs being either 4 ohms or 8 ohms. The DC resistance of 4.4 ohms shown by the multimeter arises from the series resistance of the woofer + crossover, the latter adding maybe half an ohm or so ballpark.
The actual minimum impedance is a little bit under 4 ohms, but it's up around 1.8 kHz. That's high enough up the scale to not be of any concern for a bass guitar application.
I think the Thunderchild 112 could be safely paralleled with some 8-ohm cabs and still give an acceptable "4-ohm" load, but it depends on the specifics. I figure the lowest impedance dip down in the upper bass /lower midrange region that is still safe for a 4-ohm-rated amp is about 2.5 ohms. This based on the theory that two Eminence Basslite 2010 woofers in parallel = ballpark 2.6 ohms minimum (that's DC resistance + the effects of voice coil inductance). and I have never heard of any amps having a problem driving a 2x10 cab that has two Basslite 2010's in parallel.
So I would say that the Thunderchild 112 can be safely paralleled with a speaker or cab whose minimum impedance is 5.7 ohms, but I have to withdraw my official stamp of approval if the other cab's minimum impedance is less than that. You can still try it of course, and with a little luck you can probably get away with it, but I suggest getting the opinion of your amplifier manufacturer first, and/or trying it out in practice before betting on it at a gig.
Here's an online calculator you can use to figure out the ballpark minimum impedance for two paralleled bass cabs:
Consider the minimum impedance of the Thunderchild to be 4.5 ohms, as that takes the DC resistance of the driver + crossover + contribution of inductance in the 100-300 Hz ballpark into account; and as I said we can overlook the actual minimum up around 1.8 kHz because it's not in a high-power region for bass guitar. Note that the actual minimum impedance of an "8 ohm" cab my be as little as 5 ohms, so you should try to find out what the actual minimum is before you make the calculation. In most cases the minimum will be in the upper bass/lower midrange region; the actual minimum higher up on the TC112 because of the crossover, but that's very unlikely to be an issue in a bass guitar application.
(For the record, the impedance curve of the TC112 is quite benign as far as phase angle goes, but I think that's true of most bass cabs in the region of their minimum impedance.)
If any amplifier manufacturers come across this and would like to add insights and/or corrections, please do so.
Just reporting in, I've been using the TCAF-112 for nearly two years now. I use it for bass, guitar, and music/movies at home. Also as a recording monitor. I use it every day for hours. No problems and I still love it.
Thank you very much, Thud!!
This is getting funny. Every since I bought the TC115 I get comments like "What kind of bass is that? That thing sound great!" or "What kind of amp is that? That thing sounds great!" No one has yet figured out that it's the cabinet that has set this rig apart.
We as musicians in general are surprisingly ignorant at how much of a change a good cabinet can make and I'll be the first to admit that I didn't have a clue before my introduction to the TC115.
So this has become my private joke. I'm even thinking of setting aside a case of beer to be given to the first person who thinks to consider the cabinet when complimenting my tone. (You guys don't count 'cause I just told ya).
My bandmates are astounded at the difference when I play the same pedals, bass, and amp through the rehearsal space's 810E and my TC112. It keeps up with the loud drums and sounds MUCH clearer and crisper.
it's the speaker that makes the sound! this is easy to forget. everything else just generates an electronic impulse.
Still very much enjoying my TC115 in many contexts. Per the comments above, the TC cabs have a unique tone profile. Nice, full low end extension, combined with no (or very little) rise in the upper bass/lower midrange, a very even mid-mid range response, absolutely no rise in the upper midrange, and a very clean (i.e., NO distortion) response all the way up to the upper treble.
This results in a cab that sounds much more relaxed and 'deeper' than most more traditional boxes, for better or worse.
Here is a quick comparison clip I did with the Bergantino CN212, the AE212 and the TC115 (which sounds very similar to the TC112 and I assume the current TC212). Quite a different vibe that is even more impactful on the gig.
The positives to the TC cabs... big, non-compressed low end and absolutely no 'distortion/character' coming from the cab... very 'studio monitor experience'. The negatives (for me in some mixes) is that the beautiful, clean, precise response of the cab from the upper midrange on up can get buried by guitars and cymbals in a loud busy mix.
In general, it is just a beautiful sounding cab, with massive low end capability (not to the point of being a problem... just very even down to that 'useful' low end for bass guitar around 50hz or a touch lower). It is almost impossible to drive that woofer into power compression. It just stays big and open at very high volumes. This cab laughs at transient peaks from slapping or whatever. Very impressive.
That being said, no amount of knob turning on my various amps makes these cabs sound much like each other (as is the case with most cabs).
Edit: I use the very clean, full range Glockenklang Blue Soul, and my A-C J bass with relatively new stainless steel roundwounds. If you have good phones, that 'sound source' does a pretty good job generating the full range, inherent tonal profiles of those cabs to my ear.
I've been shopping for a new bass lately (placed an order for a Dingwall ABZ), and a smaller head for acoustic sets. Numerous people have come over to check out the little cab with the crazy-big sound. I enjoyed the opportunity to tell people about Duke's work...
One guy in particular, couldn't get over how good my Thunderchild 112AF sounded when "underpowered" by a little TC BH250. Sure, it sounds good when driven hard, but it does pretty nicely with lower-wattage heads. It made a Mesa Walkabout sound mighty nice the other day...
Very well said. I hear you Ken, and I hear others who have been telling me the same thing: There's definitely an advantage to having some upper midrange emphasis. In the past I've avoided trying to build a decidedly "voiced" cab because I didn't know where the goal posts were, but now I'm ready to give it a shot.
I'm working on a design that will have considerably more native upper midrange presence than my current cabs. And I think I can make this upper-mid presence switch-off-able. I'm looking at several possible configurations at this point, and will do some intense prototyping once I have all the drivers that I wish to try. This will be a much more traditionally-voiced cab, quite possibly a sealed box, but with better dispersion than most traditional-voiced cabs, as the top end will probably be a Hathor-style open-chamber cone mid. Unfortunately this cab won't have the power-to-weight ratio of the Thunderchild cabs, but will still be fairly competitive in that regard.
I love owning 'both flavors' of voicing. I look forward to hearing the cab you are describing above!
What frequency range do y'all consider upper mid and are you talking spike, gentle hump or somewhere in between in a more traditional bass cab voicing?
It's not just a pure frequency thing, or else you could EQ one cab to sound like another. It all has to do (IMO and IME) with the break-up characteristics of the top of a driver.
My guess is, the general area around 1K is key. If you get it wrong, it sounds harsh and ganky (like some mid driver loaded cabs). If you 'crossover it out', like with the Thunderchild, it is almost impossible to dial in (IME).
Again, none of this is wrong or right or better or worse, it just is different. I again, have never been able to 'EQ' one cab to sound very much like another cab. It is why I have a few different cabs, all of which I like very much, and all of which do different things!
I certainly understand your curiosity, but for right now I'd like to keep the specifics under my hat. Figuring out "where the goal posts are" took me quite a while.
OK. I'm pairing a max 9.2 with the 212 and I was just looking for some EQ points to play around with.
I can turn the knobs and experiment but I was wondering if what yall were talking about is what I think you're talking about.
The "crossover it out" comment has me a bit curious as well.
Okey, look for a PM soon...
I've had some delays on compression drivers for the forthcoming TC112-8 (thanks for your understanding, those with orders in place), so I've taken the opportunity to spend a bit more time refining this and that. The TC112-8 will incorporate a couple of significant changes over the original, in addition to being an 8-ohm load instead of a 4-ohm load.
First, the TC112-8 will have a 90 by 90 degree horn (with a new polymer-diaphragm compression driver), instead of the 90 x 50 degree horn that I've been using. The idea is to increase the vertical dispersion so that it's easier to hear the overtones when you're standing very close to the cab.
Second, the TC112-8 will have a switch that lets you toggle between "midrange smooth" and "midrange aggressive". Won't be the snarliest cab ever, but will do the "cut through the mix" thing better than the smooth voicing my cabs usually have. We'll also have the familiar top-end rolloff switch, giving us a pretty good variety of voicings available even before you start to fine-tune with the EQ functions on your amp.
That sounds very intriguing Duke ...
A quick question, especially aimed at those of you whose cabs have the rear-firing tweeter:
Do you find that your drummer benefits from the rear-firing tweet, by being able to hear what you're doing better? Or is that not really an issue?
Would you rather it be a bit louder, or a bit softer?
Have you ever found it to be detrimental?
Yes, although I play without a drummer a lot of the time.
Nope, you nailed it the first time.
Nope, it's way too subtle to mess anything up. I'd really miss it if it weren't there though.
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