peniku8

Ricci might have adjusted his inputs based on the measurements posted some time in the past, to match the measured response. IIRC he said that the proximity to the back wall also pushed the port resonance down a bit, but I'm unsure how you ended up with an even longer port. I have not looked much into the Skram

You mentioned the port dividers and how they add more wall area to the port, which made it sound like you were thinking about removing them. If you did so, the panel vibrations of the outer (now unbraced) side panel would introduce more distortion that removing the braces would lower it. That's what I was refering to. I still think vent noise can almost completely be ignored in 25Hz and above PA applications, while port compression needs to be minimized. If you think about your wall area and air friction so much, maybe try polishing the inside of the port or apply black paint -> clear coat -> polish. I'd be interested to see if theres any difference

afaik the SB18 and SB28 come with the BMS drivers, while the KS28 uses the B&C.

I think you misread my comment or quoted the wrong post. Power compression is the compression introduced through heat (electrical), which I was refering to. And thanks to @radulescu_paul_mircea I know now that the drivers in the KS28 seem to be the 18SW115. That and some measurements I've found on the internet (especially voltage sensitivity and distortion measurements) were very valuable information for me. Now I feel less intimidated by the huge numbers, which marketing departments come up with.

You mean port compression I guess? I couldn't see how power compression relates to wind speeds

I've been to an indoor show tonight with 16 KS28 and while the system was horribly calibrated (if it was, even), the bass was just ridiculous. I've never been to a show this size (2000 people) where the bass drops were so loud that they would make your clothes vibrate below 40Hz. I wonder how the SKHorn compares to the KS28. The Skram vs SB18 should be a clear win for the Skram since the SB18's F10 is 32Hz, but the KS28 has an F10 of 25Hz, similar to the SKHorn. I'd love to have the KS28 tested on data-bass, but it's unlikely that somebody lends you a cab worth 10 grand, which might break during testing.

It can vibrate, but as long as it doesn't hit anything else or it breaks apart it won't make any noise.

It's unlikely that there is any device at all between a piece of outboard gear (like the tape machine) and the Audio Interface. High-end audio interfaces are also usually DC coupled, so you'll get all the goodness you want. And yes, this type of noise might've also been introduced by some plugin emulating an analog environment. Be it the Kramer Tape or a simple compressor like a Fairchild 670 simulation. The API2500 hisses notably when you have some heavy limiting later in the chain. That was mostly HF noise thou

@SME I have a Tandberg 10XD tape machine here, which we use for analog masterings sometimes. I could test if something like this somehow introduced ULF noise along with its usual tape distortion (which ist mostly noticed by its harmonics above 2khz). Running it through a tape machine is essentially the same as digitalizing an old movie (from a reel), since its audio track is stored on the same reel. I doubt that the hardware on something like the Cintel is inferior in quality, but the noise might've been present in the original track. Tape decks are often overdriven to create more distortion, which is then mixed to the original audio. Dunno how common this is in the movies, but this or something similar is done to most studio recordings

@SME it is very likely that most audio material in a movie ran through a de-noising process at some point. It might not bother you if a single recorded track has some noise (because the S/N will still be excellent), but when you start adding other tracks with the same amount of noise the noise just adds up... iZotope RX7 is the most widely used audio repair program and it's very good at what it's doing. It's so omnipresent in the movie business that it's basically always the first thing that is being done to an audio track before it's even imported into Premiere/Final Cut/Resolve. The target it usually broadband noise, so the ULF part is automatically reduced along the way. If you have some special kind of noises like steps, you can also filter that out selectively. When composers write a score employing a large orchestra, there is not always budget or time or just the need to hire hundreds of musicians to play the entire score for you. Often the score will be made from sample libraries (or even a mix of both). During a complex (rather: large) piece, there are (literally) thousands of audio samples playing at the same time. Imagine all those samples with background noise.. It is also pretty rare to see movies with a constant noise in the sub 20Hz region throught the entire length of it. (U)LF noise can come from mics not properly shock mounted. If you place a mic on a stand without rubber feet and place that on a wooden floor, every step will generate some LF noise. Worse in a car etc. Also: Software is not always 100% reliable and might do some wierd things. It has happened to me alot... We might discuss these kind of things for days, but we will still never find out why certain things happen.

Why do you think that they would add noise to the DTS track? That's a little out there imo. It would make sense saying that they noticed the noise in the DTS tracks, which is why they removed it for the newer(?) Atmos mix

As for max output it's essentially the same as the DS or the LaVoce, but falls about 1db behind under excursion limit and is less than .5db ahead when power limited. I'm unsure if the Leb of 0.001mH is correct @Ricci

Well there are people selling cable lifters, so it seems to be easy convincing people that they need something. Your approach has the benefit of actually being the best upgrade somebody with a good system can get, so it should be easy finding somebody to quote something like "after spending so much money on hardware with little improvement, I was baffled that there was such an improvement to be had for comparably little money" just a little shorter. Targeted marketing should also be fairly easy. Go to Facebook to place an ad (paid post) and you can select people who're living in your region and like the facebook page of marantz for example. That way you'll reach almost only potential customers and your conversion rate is high. Marketing is a huge subject thou which isn't easily explained.

If anything keeps you from starting a business, just do it! Do what you enjoy doing, and if you can make money with it it's even better. Despite running a recording studio, doing live sound and filming music videos I'm also thinking about selling PA subs. I've got two designs which I really like and will build to test. If they work well and turn out as I modeled them they're going to be great subs and I will add a few of them to my live rig. Do you want to make this a local business or like traveling all over the states (or where you're living at?). Would be awesome if you could somehow do remote work, but calibrating a room without being physically present in the room itself might be a little difficult. At least cumbersome and you won't know if it's perfect since the mics don't always tell the whole story clearly

For scene gigs the sound guys are always underpaid, sadly, but from what I've heard the local scene here in Germany seems to be much better than in the states. I talked to one Hardcore band from the US a year ago and they said that small venues have a hard time surviving due to tax and noise complaints. They were pretty happy with the situation here. I used to mix lots of local shows in the past, but I don't really accept many of those anymore. I'm done bringing high quality mics and my console just to mix a show on a PA equivalent to my phone's speakers. The live stuff I'm doing now is mostly weddings, mixing large shows for a friend's band or shows with mainstream music because these pay well. If I'm bringing the PA there will be l.acoustics with my soon-to-be-built subs, so I'm always happy and don't run out of headroom. Will be building two 12's and two 21's of my own designs. They model nicely and I think I'm starting to have my CNC under control now lol.

Loving it, man! We've played a few shows in tiny venues with karate kids clearing the pit every now and then. Let's say we were a little more Hardcore-influenced a few years ago 😁 The problem with triggers is that the sounds are either horribly sounding samples or just not mixed for a live gig (i.e. way too "clicky"). Many engineers would just turn it up and it theres no bass in the sample they wouldn't even bother equalizing that. Our setup would allow me to pre-mix the sampled sound as I'm always carrying a rack mixer for our IEM system, which already pre-mixes the guitars and bass sounds anyways. It's a very convenient setup, where the sound guy can just grab all our signals from our console, except drums. And we literally only have a single equipment rack, as guitar amps, bass amp and backing track player are all in there. And a single person can carry it. All-digital equipment is a real blessing. Hated hauling around full stacks and stuff. The last gig we played, they had 4 15" subs there, which should've been enough for the ~100 people present, if it wasn't for the fact that the cabs sounded like they were tuned to like 60Hz and the sound guys had no clue what they were doing. Of course I could jump the console and do it myself, but I still didn't figure out how to play the drums on stage and mix at the FOH at the same time..! I implemented a sub-octaver into my default console scene now, which is one absolutely brilliant tool to fatten-up the sound of low toms and the kick drum. I don't always need or use it, but when the kit on stage doesn't produce the sound I'd like, it's a blessing. Especially when it isn't tuned properly or the heads look like they've survived WWII.

I get what you're saying about feeling, but for me it's all about the overall sound, both when I'm behind the kit or in front of the stage. I don't play with triggers live, but thought about setting it up for our IEM system. And yes, the gigs are exhausing 😅 https://www.youtube.com/watch?v=7-awEQjlSk0 [Live] https://www.youtube.com/watch?v=PA6-rMbrF1E [Recording] To get back on topic, for our shows the bass drops need to be as loud and go as low as the system can handle of course!

Oh ok, that's alot of power for the mid/high section. It's unlikely that non-center signals are peaking in the mix so yes, left and right should add coherently on spikes since they're playing the same signal. Now since they're spaced and it's just two speakers and not four as I thought you might substract something like 6db from my previous assumptions. Keep in mind that is based on your statement that you've seen the clip lights flicker, which makes me assume that it's the case for all four amp channels simultaneously. And it's all just theory, in praxis, it is almost always very different, especially if this is not outdoors. Try just setting up the umik with a laptop and rew during soundcheck and you'll see what averages and peaks you're hitting. I say 'peak' but mean maximum short term rms values. 'True' peak values are not too useful

If your 4 tops are clustered that would make around 133db at 1m at 128W into each top (double the power equals ~3db gain, having twice the speakers makes ~6db gain if perfectly aligned). You can substract 5-6db per doubling of distance if the tops don't have an exceptionally narrow throw (like line arrays) so it should be about 8db less at 3m. Maybe the effect is less grave at close range thou since humidity doesn't come much into play at short distances, so it could be even louder. For SPL measurement I use my iPhone, which was calibrated with a UMIK. Factory settings were (only?) like 2db off in the "Mobile Tools" app I'm using.

I've mixed shows where the PA with only vocals on it could hardly keep up with the dumkit in the room. I'm talking 120dbA here, room for 150 people. No acoustic treatment, often not even half full. Hardcore drummers with a Snare drum forged on Mt. Doom. I don't mind a little stage bleed in mid-sized venues, as it usually just results in a 1-4khz boost in the cymbal range. That's what we can bring cympads for if it gets out of hand, but at some point it's just too much. It's all about optimizing the sound at the FOH and you have to find the right balance. And if you have issues playing a little less loud (ofc I wouldn't expect anyone to reduce his Metal drumming to conversation volume) you just need to practice more. I've been playing the drums in an Orchestra for 15 years now, that's where you really learn to control your dynamics. On the other side I'm also playing live shows with my Deathcore band and mix engineers often wonder why I'm playing so quietly heh. The 100dbA I was talking about was during the songs with 3s average. Long term average over an entire show (Swiss, Z7, 1200 guests, huge venue) was 95dbA. It was a Punk show, so pretty low crest factor stuff. I was told to stay under 100dbA long term average and was a little intimidated by the main guy telling me that he'd turn the PA off if I exceeded that. He turned out to be a really nice guy thou and told me a story where some guy started a show with 10 minutes of 120dbA average and he just shut the entire thing down. Some people really seem to lose their mind on the mixing desk. A friend recently had problems with loudness measurements at an outdoor event, where he saw the volume exceeding 120db periodically in the logs and they just couldn't figure out what happened. After some investigation it turned out to be freight trains passing by. Great choice of mic placement

120db was unweighted or dbC. You wouldn't enjoy a concert at 120dbA. When I mix shows outdoors or indoors in a venue with a capacity of say 500 and up I like to keep the dbA average at 100, because that's where it 'excites' you but it still doesn't hurt. That also happens to be the European standard and limit/goal for Rock concerts usually. When observing the db meter I noticed that some crowds (cheering of 1000 people and more) easily exceeded 100dbA. When mixing shows in smaller clubs you'll notice that the un-mic'd drumkit already exceeds 100dbA and you're left hoping for the drummer to accept your request for playing quieter or you can't really mix. Legally, you'd have to end the gig halfway through, because the band was 'using up' their loudness units too quickly. I've got two smaller shows in Austria next month, I'll have a look what dbZ I'm usually reaching, but my guess it that it's gonna be around 115db-120db while the kick drum is playing.

I've recieved the two 4 Ohm 21DS115's today and I can't help but feel that they have a bigger magnet than their 8 Ohm siblings. I'm too lazy too move the SKHorn and open it up to have a look at the 8 Ohm drivers in there; does anybody else own both versions of the driver and noticed a difference? The only obvious difference was that one came with the fast-on/solder terminal and the other with spring loaded binding posts.

@Ricci I got some time to test the interface today and found just a single PC Oscilloscope software that was able to use the audio input as input device. It is a little cumbersome to use and not very feature-rich, but offers what I need. The meter on the interface is a true RMS meter but gets a little wonky below 20Hz. I tested my amp and it started limiting at 132V RMS, which is about 187V peak. Voltage peak limiter was set to 190V, interesting! The software should work just as well with the other attenuation box mentioned, but with that one you won't be able to do ultra clean low level measurements.

Btw I posted the Skhorn driver comparison to the Skhorn thread. Skram should be similar (in terms of differences between drivers). Noteworthy is that the cheaper drivers all offer the same headroom, the Eminence more bottom end headroom and the IPAL more overall headroom. IPAL is above the Eminence at all frequencies, the difference ranged from a fraction of a db to like 3db around 80Hz iirc. I also just ordered two more 21DS115, but I won't be building Skrams, or I could post some measurements. I'm currently more interested in my own design, which models just to my liking (Skram is too big).

You should model with the input of the 6(?) complex inductance parameters, which are usually not to be found in the T/S parameters the manufacturer lists.