AudioKinesis Cabs Part VI...

[Mark Sacchetti]

Ruben called to say he used his TC115 v2 tonight and is ecstatic over the tone! Clean, crisp tone that wasn't lost in the mix. He was playing blues and R&B. The B string was clear and a mofo !

 

[DukeLeJeune]

Ruben called to say he used his TC115 v2 tonight and is ecstatic over the tone! Clean, crisp tone that wasn't lost in the mix. He was playing blues and R&B. The B string was clear and a mofo !

Thank you very much, Mark! Give Ruben an awkward hug from me!!

 

[Smallequestrian]

The advantages are better dispersion both horizontally and vertically - you can hear the overtones from virtually on top of the cab - and a more relaxed, unboxy, "open" sound. The disadvantages are a more complicated (and expensive) build, lack of backpressure at low frequencies to protect the cone from over-excursion, and a relatively large amount of internal volume gets taken up by the midrange driver(s).

Finally got to gig the cab this weekend after having it for a few months. Was particulary divey bar and had to be pretty on top of my amp. The open air chamber really paid dividends.

 

[steve_rolfeca]

Cool. That would be my one and only beef with my amazing Thunderchild 112AF. On crowded stages, I have to be diligent about raising/angling it in order to hear a balanced tone when standing too close. My rule of thumb is that if I can't see at least half of the screen in the horn's throat from where I stand, I'm not going to be happy...

I suspect that the Hathor 112 is going to be Duke's crowning achievement in terms of portability, and usefulness in applications like pit orchestras, house concerts, etc.

 

[DukeLeJeune]

Finally got to gig the cab this weekend after having it for a few months. Was particulary divey bar and had to be pretty on top of my amp. The open air chamber really paid dividends.

Glad to hear it's working as advertised!

As mentioned a page or two back, I'm planning to bring out two more Hathor-style cabs in the near future, as I think that open-format mid chamber gives me a way to compete with good cone-mid bass cabs without simply copying what they're doing.

Cool. That would be my one and only beef with my amazing Thunderchild 112AF. On crowded stages, I have to be diligent about raising/angling it in order to hear a balanced tone when standing too close. My rule of thumb is that if I can't see at least half of the screen in the horn's throat from where I stand, I'm not going to be happy...

I suspect that the Hathor 112 is going to be Duke's crowning achievement in terms of portability, and usefulness in applications like pit orchestras, house concerts, etc.

It is feedback from bass players that let me know I needed better vertical dispersion.

One reason why I didn't use that baby butt cheeks horn from the beginning is my own prejudice against older horns (it's a bi-radial, which dates back to at least the early 80's). But when I finally tried it, well it sounded very good.

Unfortunately it isn't practical to retrofit the new horn, because the cut-outs are obviously quite different. Not that the original sucks, but now that I have a better appreciation for the needs of bass players on a tight stage, I'll use horns with the wider vertical pattern where possible. Note that many if not most tweeters used on bass cabs are "bullet" tweeters, which tend to have a rather narrow pattern (like 40 degrees or so). Turn 'em up and they bore a hole through the back of your knee.

In an earlier post I alluded to a "new feature" that was going into the Hathor 112... well, I spoke a bit too soon. The new feature isn't really a worthwhile improvement in that cab, but it will probably show up in something else, where there's more room for improvement in the area it addresses (uniform dispersion).

 

[LeonD]

Here's my review of the Thunderchild 115-8. Sorry for the length; this is what happens when you're typing in a coffee shop waiting for your tea to cool. I've had it for a couple of months now but wanted to get some playing time behind it before posting a review. Since I've owned it, I've used it on a gig (duo with an acoustic guitarist/vocalist), numerous band practices and filming a music video (in a warehouse).

For background, I use an MTD 434-24 and a GK MB800. For the last few years I've been using a Bergantino AE112 for small and drummer less gigs. I'd add a Berg 210 if there was a drummer. The Bergs sounded fine but after one gig on a hot summer day with a two story fire escape load in, I decided I wanted a one cab solution for all my gigs.

There was a TC112 for sale on TB so I decided to give Duke a call with some questions about the cab. After an hour plus conversation, I found I had put a deposit down on a TC115-8. (Duke should be nominated for salesman of the year. Before the call, I would have sworn no money was going to change hands. By the time I hung up, not only did he have my money, I felt good about it. )

After some heavy handedness from FedEx and going across the country twice, I finally had my cab. The first test would be the acoustic duo gig. To say the venue is acoustically terrible would be a compliment. The amps and cabs are against a wall under an eight foot overhang. The musicians and listeners are past the overhang with a thirty foot ceiling. And, over the course of a set, there can be anywhere from ten people to a hundred in the venue. When I first started playing the difference in sound was amazing! The guitarist/vocalist (who doesn't usually comment on my sound) noticed a major difference. The biggest change was that the sound seemed to come from all around and envelop us. Not at all directional. And the sound was clear and distinct.

Since that first gig, I've had numerous practices and the warehouse filming. In each case, this cab has exceeded my expectations. Compared to my Bergs, it's a completely different sound. The difference IMHO is how the TC transitions thru the frequency spectrum. From the lowest to the highest frequency, it just seems to cross it; hard to tell where one grouping (bass, low mid, high mid, treble) ends and the other begins. And while I didn't think the Berg had any holes, the TC is a whole new ball game. It made me rethink how I eq my bass and effects.

Regarding the one cab solution, while it's height can be a little tall on smaller gigs, the footprint is less than my 112. And the weight comes in at less than 37 pounds. Win for me!

Regarding the cab and it's features, there's the bright defeat, upper mid boost, port plugs, handles and combo jacks. For me, for a feature to be worthwhile, it has to work on a gig. If I can only hear it in my quite music room with no other noise and me looking north under a full moon on a leap year, then it's not worth it. :roll no: I need to hear the difference while playing out in a mix.

• Bright defeat - cuts down on fret clack. I usually leave it off unless I'm looking for that dark, P bass with flats, blues vibe.
• Upper mid boost - this one I just don't hear. I'll keep trying it. Maybe in some situations it'll become evident but it hasn't yet.
• Port plugs - very noticeable difference in the low end quality. Plugs out equals drowning in low end goodness. Plugs in equals getting hit in the chest with a low end cannon. I live for tight bass so these will be in for me 90% of the time.
• Handles - the top handle is good; the four sided side handles rock! Every cab should have them. They make loading in and out of a trunk so much easier.
• Combo jacks - I was concerned about the speakons because my amp is only speakons and I only have one speakons to speakons cable; no backup cable. Then after owning the cab for a month, I realized it was a combo jack! Surprise, surprise, surprise (in my best Gomer Pyle voice). When will the goodness end?

Here's a quick pic from the warehouse filming.

 

[DukeLeJeune]

There was a TC112 for sale on TB so I decided to give Duke a call with some questions about the cab. After an hour plus conversation, I found I had put a deposit down on a TC115-8. (Duke should be nominated for salesman of the year. Before the call, I would have sworn no money was going to change hands. By the time I hung up, not only did he have my money, I felt good about it. )

Muu-hoo-haa-HAA-HAAAAA!

Ahem... I mean... gosh, how did that happen??

The first test would be the acoustic duo gig. To say the venue is acoustically terrible would be a compliment. The amps and cabs are against a wall under an eight foot overhang. The musicians and listeners are past the overhang with a thirty foot ceiling. And, over the course of a set, there can be anywhere from ten people to a hundred in the venue. When I first started playing the difference in sound was amazing! The guitarist/vocalist (who doesn't usually comment on my sound) noticed a major difference. The biggest change was that the sound seemed to come from all around and envelop us. Not at all directional. And the sound was clear and distinct.

... From the lowest to the highest frequency, it just seems to cross it; hard to tell where one grouping (bass, low mid, high mid, treble) ends and the other begins.

*bask* *bask* *bask* thank you thank you thank you *bask* *bask* *bask*.... Seriously, that's what I try to do, is get the different drivers blending so that the net result sounds pretty much like one voice. It's mainly a matter of focusing on the off-axis response more than the on-axis response, particularly as we pass through the crossover region. I think that off-axis is where we generally find the most room for improvement, and imo this applies to bass cabs, studio main monitors, and home audio.

For me, for a feature to be worthwhile, it has to work on a gig. If I can only hear it in my quite music room with no other noise and me looking north under a full moon on a leap year, then it's not worth it....

• Bright defeat - cuts down on fret clack. I usually leave it off unless I'm looking for that dark, P bass with flats, blues vibe.
• Upper mid boost - this one I just don't hear. I'll keep trying it. Maybe in some situations it'll become evident but it hasn't yet.
• Port plugs - very noticeable difference in the low end quality. Plugs out equals drowning in low end goodness. Plugs in equals getting hit in the chest with a low end cannon. I live for tight bass so these will be in for me 90% of the time.
• Handles - the top handle is good; the four sided side handles rock! Every cab should have them. They make loading in and out of a trunk so much easier.
• Combo jacks - I was concerned about the speakons because my amp is only speakons and I only have one speakons to speakons cable; no backup cable. Then after owning the cab for a month, I realized it was a combo jack! Surprise, surprise, surprise (in my best Gomer Pyle voice). When will the goodness end?

Glad to hear most of the features made a worthwhile difference, and it sounds like I've seriously overstated the difference that the midrange switch makes. *unbask* Hey thanks for telling me, that is very useful information, and will be taken into account as I develop my next generation of cone-mid cabs.

Duke

 

[Freddels]

But your website states that production of the TC115 has been suspended. Is this still the case?

 

[Mark Sacchetti]

He's making v2 series of the TC 115

 

[DukeLeJeune]

But your website states that production of the TC115 has been suspended. Is this still the case?

I'm doing Version 2 of the TC115 in 8 ohms only at this time, V2 indicating the new "baby butt cheeks" horn. The 8-ohm version uses the stock Kapplite 3015 (non-LF), so we trade off a little bit of low end extension for higher effiicency: 98 dB efficient, but -4 dB at the 62 Hz first overtone of low B instead of -3 dB. That's the cab LeonD is talking about.

 

[LeonD]

To further support these cabs being bass PA speakers, our drummer uses electronic drums. After we finished recording, someone was trying his kit and he mentioned we should try it thru the bass rig.

OMG! One of the best drum sounds to be heard. People just stopped and listened. Thinking if a good thing is good, then more would be better, I opened up the two closed ports. I thought we were going to take the building down with the low end. Massive.

 

[Freddels]

I'm doing Version 2 of the TC115 in 8 ohms only at this time, V2 indicating the new "baby butt cheeks" horn. The 8-ohm version uses the stock Kapplite 3015 (no-LF), so we trade off a little bit of low end extension for higher effiicency: 98 dB efficient, but -4 dB at the 62 Hz first overtone of low B. That's the cab LeonD is talking about.

I'll be checking out Leon's cab soon.

 

[DukeLeJeune]

To further support these cabs being bass PA speakers, our drummer uses electronic drums. After we finished recording, someone was trying his kit and he mentioned we should try it thru the bass rig.

OMG! One of the best drum sounds to be heard. People just stopped and listened. Thinking if a good thing is good, then more would be better, I opened up the two closed ports. I thought we were going to take the building down with the low end. Massive.

Wow, very cool! Thanks for posting this!!

I speculate that one of the reasons it worked well is the unusually wide, even radiation pattern. Not quite as wide as an actual drumkit of course! But still a bit closer first approximation than normal.

Tell your drummer to hold out for one of my 118 cabs. I'm going to at least prototype a 118 that will have a PA-subwoofer-class bottom end, and an even wider pattern (assuming I do my part well).

 

[DukeLeJeune]

I hope ya'll don't mind if I transplant excerpts from a couple of posts in another thread, as they just happen to focus on something I'm working with right now. I normally don't post about every little experiment run in my lah-BORE-ah-TOR-ee, as most don't pan out, but this might be of interest so here we go:

These [benefits of wide, uniform dispersion] are very desireable attributes, but quite difficult to obtain with cost-effective speaker-in-a-box designs.

Meyer Sound has several publications where they deep dive into the various solutions and their end results.
Cross-fire designs are not recommended, due to the big hot spot in the field center.
Splay designs are complex builds and beyond the price points of a typical bass player budget.

and

Cross-Fire = Inward Splay.
Yes, BFM favors the inward splay, closely coupled.
He did this with the melded piezo array, and the XF guitar cab.

Meyer Sound published extensive polar analysis on the various splay combinations, and found Inward Splay = Not Recommended.
There is a very hot center spot (power alley) with inward splay.
My money is on Meyer.

Some posts up, you have a graphic of a multi-cell HF horn.
The only thing wrong with this design is the cost.
The individual horn segments keep the horn wall dimensions within bounds for short wavelength frequencies.
The outward splay increases the coverage angle without resorting to diffraction....

You are on the right track for wide horizontal dispersion, for standalone cabs.

Thank you sir!!

When bgavin brought up splayed arrays in that other thread, well I 'bout choked. Two of the designs I'm currently working on use splayed drivers. The intention is to get a wider useful radiation pattern, of course.

Now as to inward vs outward splay, here are my thoughts: This is one of those things where ALL of the specifics matter. And the specifics include driver size, spacing, what frequency range we're interested in, splay angle, and anything that modifies the individual drivers' radiation patterns (like cone breakup or a horn). In the farfield (which is all that matters for this application), an inward-splayed array behaves like a slightly wider-spaced outward-splayed array. Both can have a "power alley" up the middle at some frequencies, and both tend towards a "two-pronged" pattern at high frequencies, where both drivers are beaming significantly.

With the same splay angle and same center-to-center spacing, an outward splay will generally be smoother than an inward splay. But if we take that inward splay and reduce the splay angle, we can recover much if not all of that lost smoothness, trading off pattern width along the way. So I wouldn't write off inward splays, as imo they can still offer worthwhile improvements in pattern width.

A quick search did not turn up which Meyersound papers bgavin was referring to, but my guess is that they were looking at arrays of self-contained loudspeaker systems, wherein the center-to-center spacing was maybe two feet or more.

Now by splaying drivers, instead of splaying whole cabinets, our center-to-center spacing is a lot smaller than what Meyersound was (presumably) looking at, and smaller spacing is desirable. The bad news is, splaying the drivers is not a panacea. Most of the configurations I've modelled don't look to me like they're worth the trouble, often because the net improvement is only over a limited bandwidth, above which the effects of the splay are questionable if not detrimental.

 

[DukeLeJeune]

Also imported from the other thread:

Re: the hotspot up the middle.

Would that not depend almost entirely (in the horizontal plane) on the angle of the crossfire and the distance between the sources being crossfired? I mean, it wouldn't be that hard to create a "hole" in the middle, or a hotspot, or fairly even, by manipulating those angles and distances with respect to to radiation pattern of the tools being used, no?

In my little backroom/backyard experiments, I found it was anyway. No labratory here, just equipment and ears. With a wide crossfire angle, wide coverage wasn't that hard to achieve with fairly even sound. When messing with a 4ohm 410 " 1/2 svt " for guys who want to turn their svt's up and still get asked back, the "ideal" crossfire pattern was not ideal. Too "clean". By using a pretty shallow crossfire angle built into the cab, you can achieve a bit better coverage throughout the room, but if you go too far ( and it isn't that far ), you lose the "ballsy" sound and lose the "kick in the pants" feeling for the player.

Point is, crossfire can be good and bad for several things...or for the same thing....depends on where the goalposts are. I play a couple places that are outdoors, shallow, and wide. I crossfire my mains across the dance floor all the time......it proves to be better sound both for the up close "into it" audience everytime, and equally as enjoyable for the off to the sides, further out, "sitting and drinking and talking and maybe thinking about dancing" audience.

Mains in mono of course.....the only way to fly.

I don't think anybody can say, "well, this is the best way because of A, B, and C". The answer, as it often is, is, "it depends"......

Good job with your experiments! Your experience is consistent with my computer modelling (and my living room observations), except that I hadn't noticed or predicted the loss of impact from going too far with the splay. Thanks for passing that along!

As in most things audio, splayed arrays are a tradeoff, and choosing the optimum splay angle is a juggling of tradeoffs. I've also found that fairly shallow splay angles seem to give the most net benefit.

For a crossfired 410, I'd expect something in the neighborhood of 15 to 20 degrees of toe-in (for each side) to work well. More aggressive splay than that, and the "hole in the middle" starts working its way down in frequency... plus, there's the loss of impact that you reported. Still the optimum angle for a given application may end up well outside this range... in other words, as you said, "it depends".

 

[bgavin]

IMO, empirical testing iterations are the only way to determine the ideal angle.

For example, you want a 4x10 to present the widest uniform sound stage.
I would build two 2x10 vertical prototypes, with the inner (common) side at a 45-degree angle.
Place the cabs side by side where the two baffles form a combined angle of 90 degrees.

Take measurements in open space.
Create an arc at X feet from the baffle.
10 meters at 100 watts, freespace, translates directly with published freespace sensitivity charts.
If you take groundpland measurements, cut back to 50 watts for the groundplane correction.

Mark points at various degree points on the arc, i.e. 22, 45, 68, and 90.
Record RTA sweeps at each angle point.
Vary the combined baffle angle until you get a uniform response across your desired frequency range.
The intent is changing the splay angle so on-axis response matches 45-degrees off-axis.

This will give you a working result, from known drivers, and a known baffle configuration.

 

[DukeLeJeune]

IMO, empirical testing iterations are the only way to determine the ideal angle...

What I do is run a suite of measurements on a single woofer, and then knowing how it behaves out to 90 degrees off-axis, I can model an array with confidence. Takes a lot less time than building the complete test system and measuring it outdoors.

 

[bgavin]

How do you model the baffle step?

 

[DukeLeJeune]

How do you model the baffle step?

I ignore the baffle step for bass cab designs. I have a program that can model it, but imo it's not a significant player in the farfield response.

For home audio, I generate a target curve by hand that takes into account whatever seems important to the application (sometimes baffle step, off-axis response, areas where audible distortion is more likely, whatever).

 

[LeonD]

Duke,

In another thread, you posted:

Soon I will be introducing a 26 pound ballpark 112 combining the Kappalite 3012LF with a single small cone mid in the same sort of open format midchamber. I guess this cab will become my sound-per-pound leader south of 40 pounds, which is the weight you mentioned as the upper limit in your opening post.

The TC115-8 is the perfect single cab for me. It handles all of my gigs, sounds great and is easy to transport. The only things is on some of the smaller gigs, the size (height specifically) can be intimidating. I was going to ask about a smaller cab when I saw the above.

Can you elaborate? How will the sound compare to the TC115-8? What will the size be? What will the cost be? Would you be willing to go down to a 10 inch speaker for a smaller enclosure?

Thanks.