Ricci
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Santo, Please read through my forum threads on the RF 19 and the testing notes and data. Much of this is already covered. You may not get a response as extended as mine without EQ. The room is a huge factor. Without the room the response would be almost exactly what is seen in the outdoor GP tests. I knew exactly what my room acoustics were doing in the bass region before I moved to the 19's. I was not guessing what the resulting response shape would be. I have no idea what it would be for your room / placements. Not recommended for sealed cabs is based on antiquated thinking from the old days before there was modern DSP. Efficient drivers with low Qts weren't recommended for sealed because the raw voltage response isn't flat and the F3 or F10 occurs at higher bass frequencies. This is almost entirely irrelevant in the modern era. Any competent pro, home, HT, cinema, DIY, system will be making use of DSP. Bass performance in sealed cabs comes down to a few relatively simple factors: Power handling, high linear displacement potential (SD x Xmax), efficiency and mechanical durability. Raw FR is far less important than it used to be. RF is a car audio brand targeting SPL competition type applications. A completely different environment than any other real world use. EQ is not usually used for SPL comps and loud daily car systems. DSP is used for SQ based car audio but this woofer is not marketed as that. However when looking at the engineering in the driver if one were to make a laundry list of design attributes that result in a "SQ" based driver on steroids it ticks all the boxes. That's why I decided to test one originally. Most of the above applies to any bass driver not just the 19. Anyway...I would start planning things by looking at your room, budget, listening habits, WAF, etc...And work a solution with a "system" approach. There are a number of viable approaches and drivers to use. IB, Sealed, vented, SBA, DBA, horns, nearfield, tactile transducers...For example a properly executed DBA is objectively one of the least compromised approaches, but not everyone can execute one in their space and you would not want or need to use SI24's, 6021's, or RF19 type beasts for that.
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4X SI 24's will be very impressive if you go that route. They are great for moving huge amounts of air effortlessly. I use the RF 19's specifically based on the engineering and quality of the driver and the objective measured performance of it. Has nothing to do with the brand RF. All of that data is available in the measurements section of the main Data-Bass site. My cabs at home are 4x sealed dual opposed. About 24.5x24.5x36" from what I recall. It's been a long time since I built those cabinets. Each driver sees about 4.5cu ft or 127L air volume. The MAUL is a quad opposed series loaded 6th order bandpass Frankenstein monster. Roughly 14.5Hz vent tuning. 47x47x30". 1086L net. 550lbs estimated. Response of the sealed RF's in my basement HT is attached. Subs only, at the main LP, no EQ, no smoothing, 100Hz LPF. You can see the 42Hz room mode caused by the room acoustics and seating position (center room). Cleans up quite well with a few bands of EQ.
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16 1 ohm...2x 2ohm that are currently unused. They were intended for a project that I never started. Imagine that! 🙄
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What is lost with higher mass (higher Xmax usually indicates higher mass) is overall efficiency. The biggest hit is in the higher frequencies. The SI 24 is very capable. It also sounds quite smooth. Very good at deep bass. Also very impressive looking visually. If you can afford 2 drivers this would make a quite capable system. At home I use RF 19's x8 sealed. At my rehearsal / work space I use RF 19's x8 in the MAUL's. I also have a pair of Skhorn's with 21IPAL's and a whole load of other cabs/ drivers sitting around or in storage.
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Hello Santodx5, Winisd does not account for the complex inductance and other effects present in the speaker motor system. In other words the responses shown will not be accurate. It is ok for ballpark estimates but not good for detailed comparisons. For this you would need an impedance measurement, or complex inductance parameters for the driver and a simulation program that would allow them to be entered such as Horn Response. This and variation in production of drivers is why the real response of the SI HS24 is different than the Winisd sim. It appears that you are leaning towards vented cabs with lower tunings. Sealed or IB is also an option for reaching deep. "Best" depends on a bunch of factors. Budget, listening habits, WAF, room size / shape/ construction, etc...
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George a Linkwitz transform circuit is likely what you are talking about. Other options are servo / active feedback sensing circuits or regular EQ can also be employed. Note that the output limitations, efficiency and power handling of the system are not changed by any of these methods.
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It could be done with a large enough printer. The issue is most printers in the hands of DIYers don't have nearly enough build area to do even medium sized horns without going to multiple pieces. The quality could be done quite well with the right setup and materials.
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Yes. Small changes like this will be inaudible. 18mm vs 12mm.
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AUS pricing for audio gear has always seemed crazy to me. Is there no authorized dealer for B&C / Lavoce / 18 Sound etc in AUS that maintains stock? EDIT: A quick search didn't bring up much. The B&C website lists one distributer in NZ but their website doesn't inspire much confidence. Mostly looks like a rental outfit for events.
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Chiko, I understand. Not everyone has enough budget to build many smaller cabs. This is a big cab...About the size of a Skhorn. 30Hz is pretty low for a scoop and requires a lot of size. Im not sure I would like that big 70Hz peak followed by a hole in the response at 100Hz, which is part of the reason I'm not a scoop guy. I always planned to test a popular scoop design but never have.
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This will be fine. These are very minor details. Do not worry.
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Plans for the Skhorn or Skram subs are in the first few posts of each respective forum thread.
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Doing nearfield subs behind the seats isn't a bad idea when you still want to feel the bass but also want to keep the volume manageable. The XLS series is a decent woofer still. For this type of use look for something with a bit of xmax since you'll probably want to boost the lower freqs where the tactile shake happens most. I'd choose something like the XLS for this versus the 15" pro woofs. Cheap 12" car woofers from JBL or Infinity could work well also. One thing to consider is the backwave of the drivers in that stair wall. If it isn't solid you may have trouble with noise and vibration from it. The drivers will be coupled to it and that wall will act as an enclosure.
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Yes...This is a good approach.
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This is a beastly looking sub. Shew it's huge and expensive though. It's the size of 2 Skhorns or 3 Skrams. That'd be a fun comparison. Fun fact it's 25% bigger than the MAUL cabs and weighs about the same. The tunings are much different though. Definitely 21DS115's...The p2p excursion listed is probably mechanical maximum. Not linear xmax. Looks like they doubled up on the wall thickness near the hatches. This is one spot I was wondering about potentially being a vibration concern. Regardless it looks like a beast. Peniku8, DSP presets can be protected in Armonia.
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You can use an LT circuit for this or regular dsp EQ filters. You will need to be able to take measurements of the subwoofer in order to develop EQ that modifies the response in the manner you want. Without measurements of the sub you are somewhat shooting in the dark. You can use simulations of the sub system to develop EQ but this will usually be in the ballpark only. Also keep in mind that EQ for flat response outside will often result in excessively boosted low end once the sub is placed in a room. Again measurements of the sub in room help a lot. If you want to play around with filters REW is free and has a robust EQ function, plus the ability to take measurements of course.
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The K-402 is listed as 39.5x22.5x16.6". It's also a BIG piece of kit, but not quite as bad as the 2360A which is just huge. Shelf EQ is required for 2" CD's on setups such as these. I don't push the top end all of the way flat on axis. I generally try to go for something similar to the Harman or JBL listening curves. A gentle and gradual slope from the lower midrange to the extreme treble. Flat from the mids to the treble sounds harsh to me on this type of setup. It's too much HF energy. Even with not EQing the top end all the way to flat it takes a lot of boost >8kHz. Thankfully there's little avg power in that bandwidth and big CD's are rugged as far as tweets go. To me the piece of data that sticks out like a sore thumb are the THD results between the 402 and the 2360A. A lot of prevailing wisdom says we are very insensitive to THD and have trouble reliably hearing differences until they become grossly distorted, but none of the other data seems to show such a large difference. The polar response is different of course but I don't think this is why the K402 sounds smoother/ more "Hifi" to me with both EQ'd and on axis. The 402 exhibits about half of the THD at roughly the same output levels. This elevated THD and cupped hands sound effect at some frequencies, is likely due to the narrow / deep diffraction slot + some amount of increased throat distortion. The 2 to 1 THD ratio tracks with the output level. I wish I had data for the 2445H on the K402 to corroborate, but it wouldn't fit the K402 due to the motor diameter.
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Nice results. Lot's of good tweeter tests out there. Not many that check the behavior at >100dB though. I'm talking about the big CD and horn combos. There's much less info out there on those and it's more dispersed. That JBL horn + CD combo weighs probably 80lbs / 36kg and is 775mm square. Awkward as hell to move around and do polar measurements. Then there's the loudness factor.
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It was most definitely uncomfortable when it got loud. I thought doubled up ear plugs with shooting muffs would be enough. I was noticing a weird sensation of HF tactile feel at frequencies you don't normally feel. Pressure, etc. No doubt that it's not going to be easy to blow a 2" exit CD outside of legit large scale events. Unless you are some kind of masochist, run it with no HPF, or hit some sort of turn on thump / cable disconnect snafu, I don't see it happening. I debated between this driver and the Radian Be driver. I was going to go that way but right when I went to purchase the price went way up. It was near $1200 if I recall. At the time I was able to get the Celestions for about $900. I do wonder how those Radian's would perform. I know they wouldn't have the lower midrange headroom or be able to cross as low, but it would likely have been good enough for a 500-600Hz XO. The top end would've been better I'm sure. Too bad it's not easier and cheaper to test this type of devices like this. It's a bigger PITA than subs! Harder to get an adequate environment, more difficult to setup and easier to screw up. Plenty of measurement sources out there but no one really goes past 1w equivalent voltages.
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any design thoughts on my custom monitor build
Ricci replied to dreadknot55's topic in Speaker Design
It happens... Maybe the OP went down the rabbit hole and has been absorbing knowledge for months. Who knows. -
Hello Chiko, Interesting comparison...I'm not surprised that the scoops sound totally different. Scoops are really efficient over a narrow bandwidth. The trade off for the efficiency is peaky response, limited bandwidth, limited low frequency output and BIG size. Most of them are huge cabs but really only have LF extension to 40-45Hz. What 's the dimensions for those scoops? Those look BIG. I've never seen any in depth measurements of a good scoop design. Did you try listening to music that has deep bass <40Hz? You should hear a huge difference. Everyone has their preferences for sound but personally I'm not a fan of running a 4 or 5 way rig with the bandwidth split up into tiny segments in the bass range. When I see the picture of the stack with the Skrams you posted...I think that 1 or 2 more Skrams sitting in place of the MBM's and running the whole bandwidth would be better. That's just me though.
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Comparison of the 2360A and K402 horns using the AXI2050 driver. In general the K402 seems to be a better more "hifi" design. The 2360A loads obscenely low in frequency and has good pattern control but it has a lot more pronounced issues and these can be seen in the measurements. Still it is a useful and listenable horn decades after being introduced. I used them for a very long time with the 2445H drivers tested here and enjoyed them. There was always a bit of extra "character" to the sound of them that I never could eliminate fully, but they had some positives also. The K402's just seem to be easier to work with and get out of the way a little more, despite also being a giant horn. Impedance. This measurement alone shows about just how different these 2 horn designs are and how they match up to the driver. Frequency response. The K402 appears to be a better match for the AXI2050 driver. The response is more sensitive and smoother overall. The 2360A has the advantage in LF extension and output <500Hz. THD at 2.83 volts. Reference the graph above. The 2360A exhibits lower THD below 400Hz but much higher THD throughout the rest of the bandwidth. 22.5 Volt measurement comparison. 22.5 volt THD comparison. Similar to the much lower volume 2.83 volts measurement, the same driver loaded onto the 2360A exhibits much higher distortion in the output. 10-20% THD vs only 5-10% or roughly half when loaded on the K402 horn. Note this is a brutally loud playback level. A comparison of the output compression occurring during the 22.5 volts measurement doesn't show much difference. There's perhaps a very slight advantage for the 2360A data but the K402 was averaging just slightly higher output at the same voltage.
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To wrap up here are some comparisons. AXI2050 vs 2445H both on the 2360A horn. Impedance. Both are nominally 8ohm drivers but the AXI2050 has a much higher avg impedance. Response and voltage sensitivity. The 2445H shows higher sensitivity, smoother response and much more extended high frequency response on the 2360A horn. Maximum level reached during testing. 2445H is with 15.9 volts input and limited to 400Hz to prevent damage. AXI2050 measurement is at 22.5 volts and starts an octave lower at 200Hz. Despite the higher voltage during the loudest measurement the output of the AXI2050 still lags behind the 2445H above 5Khz. THD during the above measurements. NOTE: The JBL was receiving 15.9 volts. The AXI2050 was receiving 22.5 volts. In general the AXI2050 has lower distortion. Keep in mind it is producing higher output below 3.5kHz and less output above 5kHz. Reference the graph above. 2.83v THD comparison. The AXI2050 is showing lower distortion but, note that at this input level the 2445H is producing more output above 500Hz. Reference the 2nd graph in this post. Output compression observed at the maximum output level reached. 15.9 volts for the JBL 2445H and 22.5 volts for the AXI2050. Again keep in mind that the AXI2050 is taking more voltage and it is producing higher output below 3.5kHz and less output above 5kHz. Reference the graph above. The AXI2050 is exhibiting much better and more uniform behavior here. The 2445H driver and 2360A combo exhibit some strange behavior in the 8-16kHz octave in this test. Most likely related to resonances and response shifting.
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Measurements of the AXI2050 on the Klipsch K402 horn. Measurement sweeps at increasing voltage. Note the 22.5 volt measurement cuts off at 300Hz. The same data normalized to show only the compression of the output as the level is increased. THD captured during the measurements. Distortion harmonic makeup at 2.83 volts Distortion harmonic makeup at 22.5 volts Horizontal response. Vertical response
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Measurements of the AXI2050 on the JBL 2360A horn Sweeps at increasing voltage. Note the 22.5 volt sweep goes down to 200Hz! Normalized data showing only the amount of compression occurring as the voltage is increased. THD captured during the measurements. Distortion harmonic makeup at 2.83 volts Distortion harmonic makeup at 22.5 volts Horizontal response. Note the 75deg measurement is missing. Vertical Response.
