m_ms

"Guesswork" to you is using one's ears to others. At the end of the day it's what matters (i.e.: listening), but if measurements is what makes your day in this specific amp context, go ahead and look up specs and try and be the wiser on the actual perceived effect. My assumption is the in-room frequency response won't change, but that's not to say there can't by any sonic differences.

In continuation of above post of mine, further changes on the amp(s) side have materialized. Whereas previously I ran my fully active setup with 3 different amps (Belles SA30 Class A, Crown K2 Class I & Lab.Gruppen FP6400 Class TD) I've now replaced all of them with 3 amps from MC² Audio's T-series (Class A/B, and fully differential balanced): the T1500 for the EV horn and two T2000's for the EV bass bin and TH subs respectively - essentially the same amps for the whole frequency spectrum, and 2350W in total per channel. For bass heads, i.e.: the most fitting context in this place, the Lab FP6400 may be the more obvious choice for subs duties with its crazy power delivery and control here, but as someone who's very much into the overall reproduction quality of the entire frequency spectrum (not to say others here don't put similar emphasis on this matter), fully outboard active at that, the all-MC² Audio amp implementation has the sonics fall into place to my ears. I actually preferred the MC² Audio T2000 on the TH subs vs. the Lab FP6400, just a subjective preference, but the big surprise was hearing the 575W/8 ohm T1500 on the EV horns holding its own, although differently, against the 30W/8 ohm Class A Belles SA30, the former in fully balanced mode and the latter RCA-coupled. Oh well, a bit off-topic being that the above crosses into non-bass territory as well.

Yesterday switched amps for subs duties; previously used my Crown K2 to feed a pair of 8 ohm-load MicroWrecker tapped horn subs (w/B&C 15TBX100's), and my Lab.Gruppen FP6400 to (also actively) power the bass bins (4 ohm load) of my Electro-Voice TS9040D LX pro cinema speakers. Now with the FP6400 taking on my tapped horns I'm surprised to find out how more hard punching, controlled and clean the bass sounds by comparison. The K2 almost sounded a bit wooly next to the FP6400 - bass "with a belly," not least down very low. The K2 on the EV bass bin however works just fine (perhaps even slightly better vs. the FP6400 here), covering only a ~85 to 600Hz range with 36dB/octave cut-off slopes in both ends. Instead of 500W to the TH subs and 2.3kW to EV bass bins it's now 1.3kW to the subs and 800W to the EV bass bins. I take it wattages is really the least of it though, as I'm never near the limits of the performance envelope of either amp. Nonetheless it's enlightening seeing how different amps can affect the reproduction of bass, even at more "sane" SPL's.

Thanks for your replies, @jay michael and @peniku8. It certainly appears the Skram is a very versatile performer, and that from a fairly limited size all considered and still hitting quite deep in frequency. An impressive combo. And of course, yes - the TH118 trades a few extra dB's in sensitivity with less extension compared to the Skram. I should've looked at little closer at the specs.. Interesting findings on the sonic differences here. They would seem to mirror what I've read earlier in this thread in a comparison between the Othorn and Skram. I use a pair of tapped horns myself (15"-loaded with a ~23Hz tune, @20cf. volume per cab), and can relate to your descriptions. They're just effortless or unflappable and indeed very smooth sounding down low, and I find that to be a great trait also when watching movies on Blu-rays/4K UHD's. The sheer LF output from movies on named formats can be quite overwhelming, not least when reproduced so cleanly and forcefully, and I remember settling on the TH principle (instead of the more classic FLH) to more readily accommodate movie soundstracks (in conjunction with music playback) and their potentially prodigious LF output, with TH's having excursion minima at the tune.

When you say a pair of DSL SH46 "outrun" 6 Skrams, is that simply in reference to the total output the SH46's are capable of by comparison, or is it more of a "feel" for the energy-balance between the SH46's and Skrams in the sort of venue you're using them? I presume the Skrams are dialed in somewhat hotter vs. the DSL's and therefore also run out of steam earlier/need more headroom to keep up? As a thought experiment, say you were using a pair of SH46's in a home environment in a moderately sized listening room (I know, overkill, but bear with me). Would 2 Skrams suffice augmenting them here, i.e.: provide a proper mains/subs balance, or would more of them be necessitated in such a listening milieu in conjunction with the DSL's? Lastly, is a single DSL TH118 comparable to a single Skram in output, even though the TH118 only uses an 18" vs. a 21" in the Skram? And in case, does the TH118 therefore make more effective use of a given driver diameter in given enclosure volume due a more outright horn-loading of the back wave of its driver, while also making use of the front wave? Both of them are high order bandpass designs, but the Skram is using a somewhat shorter "horn" loading..

Thought I might as well bring it up in this thread being it's about a design involving big-diameter woofers: How much of a problem is lack of cone control with large diameter woofers (say, +15"), also known as "wobbling"? Is it a problem mostly with very high excursion, typically no more than moderately sensitive woofers, or is it a general phenomenon and problem even with more efficient pro woofers like the 21" variants used in the Skram, Skhorn and Othorn? How much does it matter sonically and for overall performance? Is it even a real issue, and does it warrant designs using instead a multitude of smaller, say, 12" woofers compared to fewer 18" or 21" dittos?

Thanks for your take on this. It would seem the creativity needed to imagine such "particulars" in measurement approach by Magico makes for a scenario that is wholly disconnected from anything real-world. It's telling they'd venture forth with such claims (or simply outright disinformation?) seeing they believe they can get away with it, but I guess it goes to show the general lack of knowledge in this area among audiophiles and how difficult it is to justify prices of (at least) $22k and $36k respectively - that is, for a single item - without flaunting some über-impressive SPL and distortion numbers, at 20Hz no less. Sorry to be ranting, but isn't it rather typical of audiophilia to prioritize inertness of construction, finding no doubt its apex with these Magico subs for mega $$, than higher sensitivity, more displacement and bigger size? How important do you find rigidity of construction with subwoofers and the aspect of the enclosure itself - apart from the driver/port/other - as another source of distortion? Is it any real issue as a distortive source with subs like the Skram, Othorn, Skhorn etc. at anything but what approaches war volume, not to mention in domestic environments with lesser SPL requirements? I'm not saying rigidity and inertness of construction isn't important, but I'm asking to which degree.

(Off-topic, I know, but had to get below off my shoulders) Please consider the following info from Magico's homepage on their Q subs: https://www.magicoaudio.com/q-sub 136dB's at 20Hz with less than 1% distortion? They sport two sub models, one featuring 2 x 15" woofers and the other 2 x 18" woofers. Sensitivity is a rated 90dB's for both models with 2000W and 4000W amps respectively. The sealed(?) enclosures are made of aluminum and are extremely inert and heavy. Did I miss anything here, or did Magico reinvent the wheel with these specs? Going by sensitivity and amp power rating I can only muster up a max SPL of some (including loosely estimated power compression at full click) ~120dB and upwards of ~125dB's respectively, not bad by any means, but still way off the claimed 136dB's. And 1% distortion at 20Hz at 136dB's - if I'm reading the above correct?!

I did mean and actually wrote extension and not distortion I too can only speculate on the Devastator's and their design and performance specifics, so pardon for assuming what I know not, but added extension (and size) seems to be general thing with these, and so I'm wondering how that impacts upper band extension and overall behavior here compared to the Skram's and their design parameter goals. My intention implementing a pair of Skram's at a future point in my setup is to have a cleaner upper range (for a cleaner upper bass/lower mids - a vital area in sound reproduction - and also to be given more free reigns wrt. XO frequency to the mains), slightly more midbass energy/overall visceral impact and reduced size (from 20 cf. to 16 cf.), whilst also having the opportunity to tweak the tune. A pair of Dev's in some variation would likely defeat the purpose of mine, certainly with regard to size, so regardless of their qualities they're not an option in my case.

I'm sure a pair of Othorn's would be a delightful addition in my setup, but if the Skram's are their equal (with an edge in some respects) while being an easier build, slightly smaller etc., that's the way to go for sure. Many if not most things being equal I prefer cleanliness of reproduction with a more extended upper range via the Skram's, where it seems the prowess of the Othorn's is in the lower near tune performance. I take it the differences here are subtle, though. Impressive design goals and getting them to meet. Never cared for the Devastator variant(s) as it seems they're going rather blindly after extension, but at what cost in other areas of overall bass reproduction? They also take up more space. I assume top your list of the best drivers for the Skram design includes the Lavoce SAN214.50 and B&C 21DS115-4, or are you referring mostly to the Eminence, IPAL or 21SW152?

Thanks for this rundown, @Ricci. It occurred to me earlier that you preferred the Skram to the Othorn - why or how is that? I suppose the Skram is easier to build and mates well with a broader and cheaper range of drivers, is port tune-able, and may extend higher and more cleanly compared to the Othorn. Output-wise it would seem they're comparable, at least. Have you listened to the Skram in action by any chance, and if so what are your impressions subjectively speaking comparing it with your recollection of the Othorn? The latter is semi-direct radiating, and that may account for some its reported "character." Oh well, only so much can be done speculating about these matters. I guess it's the nature of not being able to listen to them side-by-side, and so trying to get a bearing otherwise is attempted. Every indication so far is for the Skram's being "tight, punchy/impactful and very clean sounding" - and different at that compared to the more classical ported, direct radiating designs. Their native tune ~@29Hz with all ports open may feel slightly deeper perhaps with the ports situated so close to the floor, which may act as a slight extension even - as has also been suggested earlier. I gather blocking one port would be sufficient for both music and movie duties - save perhaps those cinephiles who crave infrasonics. (Tidbit) Initially, prior to having my MicroWrecker's built, I actually favored the Othorn's, but the rather expensive 21SW152 was a deal breaker. So far though I've been very happy with the MW's.

What's entailed in "people really appreciating the change" from double 18's to the Skram's? What's their feedback in more detail about any change in presentation here - is it simply about (more?) capacity, or does it come down to a perceived difference in presentation between the two box and driver types? @Ricci and others: Earlier this evening I was at local cinema watching 'Ghostbusters: Afterlife' (an amusing and largely successful follow-up to the '84 original), and was quite impressed by the bass impact and overall quality in the some 400 seat auditorium (with Atmos sound). Turns out their speakers are from QSC, and the subs they use are these: https://www.qsc.com/solutions-products/loudspeakers/cinema/subwoofers/sb-series/sb-15121/ I take it the 21" driver used here is the B&C 21SW152, and I believe I've read only two of them subs are used in this auditorium, though I find it hard to believe given how much the bass shook the whole locale. My question here is: how would the QSC sub compare to a Skram, say, with the same driver? Does the Skram make more outright use of both its front and back wave of the cone by comparison, or are they comparable to one another in overall SPL and presentation?

Thanks for your findings on the driver comparison via the Skram - duly noted. MEH's - like, something of a synergy horn? That Eminence driver, even more powerful than the 21SW152-4? That's crazy. It sure is expensive, though - almost twice the price of the Lavoce where I live. Don't really see how I could justify that in a home setting never getting close to full tilt war volume these beasts are capable of. It's not that the Lavoce is a slouch itself by any stretch of the imagination. From what I can assess the Lavoce is only available in an 8 ohm version. What makes a 4 ohm ditto desirable here, if it even is? There's the B&C 21DS115-4 as well, but going by your driver tests the Lavoce fully appears to be its equal, and with distortion numbers being at least as good, it seems.

Thanks for your replies, @jay michael and @Tahoejmfc Seems like words of (general) caution from the both of you on using the Skram's in a home setup, and I appreciate the well-intended advice here. Still, I'm inclined and quite tempted to go ahead with this one way of the other (i.e.: the driver being the variable). Thanks for chiming in, Josh This would be my intention as well, plugging a vent or two on the both of them and then see how that fares. I take it a hard cut-into-shape foam compound would do the trick rather than having to block the vents with wood pieces? I like that I'd be able to tweak the tune of these and what fits most properly my specific needs. They're no doubt vicious when let loose in a moderately sized living room. I don't intend to though (at least no regularly 😁); less or no more than ~110-115dB's at the LP will mostly do. That's exactly what I'm going after. I'd be surprised if they wouldn't be able to either, but that's only based on the feedback I've heard from others. Seems I won't be disregarding the 21SW152's after all if were to find them at a fair price! The only real hold-back right now is the crazy sky rocketing of prices for plywood (I'd have these built in 13-ply Baltic birch, just like my MW's). The prices do appear to have reached their upper limit by now, so we'll see how it develops from here.

Thanks for your reply and recommendation! Very interesting info on the claimed "brutish" and "darker sounding" nature of the Skram's with the B&C 21SW152. I have for a while circled that specific driver simply because I find it to be a mean beast from all I've read, not least as reported in the Othorn. More realistically though I'm considering the Lavoce SAN214.50 and B&C 21DS115 drivers with the Skram's (4 ohm versions, which seems to be recommended over the 8 ohm ditto?), because they're also recommended as well as being cheaper options (certainly the Lavoce). Whether that would fundamentally change the possible fact that the Skram's may be too of much of a brute beast in a "HiFi" setup, I don't know. Looking at the picture of my system above though you may have guessed that I'm not the regular "audiophile" dude, and the MW tapped horn subs I have are no non-brutish slouches either. To bring a little perspective: from what I can tell the Othorn tapped horn sub is very much fitting in a domestic environment due to its (again, reported) clean, "hifi-ish" and relaxed/effortless bass reproduction. It can likely rain hell when cranked, but that's only commendable 😁 More to the point: most everything in me indicates that the Othorn would be more than doable in my own system context, so I guess the question could be posed how the Skram fares by comparison, but you've already gotten into that earlier in this thread where I was almost under the impression the Skram's were equally "civil" sounding, if somewhat more lively in the mid-bass area - which may be what gives it its "brutish" imprinting. Just Guessing. Very interesting to read as well. Could you elaborate on the differences in presentation? Two friends of mine are using a pair of Electro-Voice TL880D subs in their respective setups, and they're ported dual 18" designs that I know intricately. I've never quite warmed to them, which is also the reason I went in a different direction with the MW's. Fitting the Skram's with the proper driver for domestic use would seem a viable option..

Contemplating replacing my very good 15"-loaded MicroWrecker tapped horn subs with a pair of Skrams in my home system. Currently I'm low-passing the MW's @83Hz 36dB/octave L-R, which seems to be the limit of their upper band before starting to progressively take on a specific and undesirable sonic character here. Conversely a lower cross-over to the mains yields lesser results as well, so 83Hz really is the sweet spot in my particular context. Still, being I'm so close to the MW's hard deck I'm wondering whether another sub design with a more cleanly extended upper band, like the Skram, would clean up some of the upper bass to lower midrange range, while also making way to experiment with a slightly higher low-pass up to about 100Hz or so. At its "native" tuning with all ports open the Skram doesn't extend quite as low as the MW's, which are tuned at somewhere between 22-24Hz it seems, but blocking one or two ports of the Skram offers a ~25Hz and ~20Hz tune respectively, and so there are ways to come about a slight limitation in LF performance compared to the MW's. Being that I won't be using the Skram's anywhere near their SPL limits port noise isn't going to be an issue, even with two ports blocked - or so I gather. Will two Skram's be overkill in a home setting? Sure, but I think of it as "the more headroom the better," or certainly it can't make things any worse. I'm interested in sound quality and clean visceral impact at higher SPL's, and maybe the Skram's will bring something else to the table that's complementary to the overall synergy of my system. Any thoughts on this speculated change are welcomed. /Mikael

Is a single Skram equatable to a box containing double, ported 18's? Moreover, is there a notable difference in bass presentation between the two? Please elaborate, if you care to. /Mikael

Don't know if this video (in Norwegian) has been shared already - I presume not due to the different-language "barrier" - but it shows what can only be the Skhorn with IPAL drivers at some Norwegian fella who specializes in building (and buying) horns speakers, big subs and the likes. He describes the Skhorn sound as (freely translated) "effortless, dynamic and airy." Attributes any serious (true) audiophile should aspire to from subs, I gather, but in reality few would ever get to experience their sound for, well.. obvious reasons when speaking of audiophiles in general. I take it the Skhorn is designed with the B&C 21SW152 and/or its IPAL sibling in mind?

Thanks for suggesting the Yorkville version as well. "There was .." - are they out of production? The U15 looks interesting, and where I've found them listed are not that expensive. Question is though, and this concerns the current Synergy horns as well, whether they're dialed-in too hot in the HF-region, being that they're likely to be used where the listening distance is more pronounced (like outdoors, or bigger indoor venues)? Indeed that's crucial, because I'd be using them in a domestic environment where the listening distance won't exceed ~10-12 feet. The bass capacity some of the people here have implemented in their homes is substantial, to say the least. Skrams and Skhorn used in conjunction.. - makes my pair of MicroWrecker tapped horns seem almost puny by comparison.. 😲 Thanks for sharing your impressions. While I'd love to try out the SH46's they seem not to be well-suited in a "hifi" set-up due to the early HF roll-off, but other than that I gather they'd be a wonderful addition to one's home system, not least as HT-speakers (with subs)! The SM60F is more like it for what I'm looking at, and that you've tried them out successfully with the Skrams is important info; my intention is to use a pair of Synergy horns all the way down to my tapped horn subs (crossed in the vicinity of or slightly below 80 Hz), although I am wondering whether a dedicated midbass horn would be a better choice so to have a horn-loading here that actually acts like a horn (with dispersion control lower in frequency) and then crossing the SM60F higher? That's why I'm looking at the SM96 with a wider coverage and dispersion control further down. The SH50's would be great, but I'm afraid they're too expensive for my budget as is. Do you feel the SM60F lacks energy in their lower operating range crossed over to the Skrams, compared to the SH46? EDIT: on second thought, the Danley's or Yorkville's being too "hot" in the HF-region for domestic use likely won't be a problem in my case, being that they'll be used through a Xilica XP-3060 DSP unit anyway with DRC Designer corrections.

Off-topic, but I've noticed a poster (or two?) in this thread using Danley Sound Labs Synergy horns in conjunction with the Skrams. I'm contemplating possibly incorporating a pair of SM96's in my own set-up, and would appreciate any insight on their sound - be that pro or domestic use. You're welcome to send me PM's so not to derail this thread. EDIT: Though this paragraph from poster @jay michael is quite illuminating, it appears (from page 11): /Mikael

@N8DOGG -- And just thinking about the woofers in the main speakers are 15" drivers.. That's a rather massive sub set-up, not least in light of more to potentially come!

Not using my set-up at "war volumes" (I like that expression), nor in any pro use settings, and there are different factors at play with my system compared to yours that would have me prefer the particular cross-over choices (slope/type and frequency) I've made between the mains and subs. That being said I wouldn't go with a gentler slope, by rather a steeper one - if you can. In my set-up I find there's a "plateau" or leveling of virtues or qualities if you will with a 36dB/octave Linkwitz-Riley slope between the mains and subs. Lower than that and the sound starts becoming a tad too placid (loss of energy and firmness), and higher than that the sound becomes a bit high-strung or tensely wound-up. 30dB/octave L/R is close, and with some music perhaps preferable, but overall I prefer the "energy coherence" of the 36dB/octave L/R slope. I use a 20Hz 4th order BW HPF on my tapped horns, and they're crossed at 78Hz. Would love to cross higher than that, but though I've yet to try out crossing in the 95-100Hz region more thoroughly (which may be preferable with my mains), I fear it'll challenge the upper range cleanliness of my TH's. Actually a friend of mine may try out building a pair of Othorn subs to augment his all-horn mains (WE 12a replicas made of wood), and should he not be too pleased with the pairing (I somehow doubt that), the Othorns may find a way to my setup - an exciting thought.. I guess in your case I might try out a 105-110Hz cross-over with a 36dB/octave L/R slope and see how that works..

Essentially, isn’t a tapped horn exactly that - a 6th order BP?

Heard a bunch of those KS28's at a Rammstein concert earlier this year, and I must say the sheer wallop and physical presence they delivered was rather astounding. In a some 50,000 ppl stadium we sat about the furthest away from the stage we could, in the upper balcony, and yet the bass pounded in a manner almost beyond belief. It mayn't have been great bass per se, but it sure as hell was physical, dense and loud! Btw, I thought the KS28's housed BMS drivers?

Would a Danley DTS-10 get there? EDIT: Of course, the DTS-10 is likely beyond proposed budget..