A "true", as in accurate or exact low frequency monitor would not contain resonant effects.
The sealed Yamaha NS10 has been used by more recording engineers than any other monitor since it's introduction in 1978. It rolls off at 12dB per octave below 100Hz.
From that time period to now, large ported studio monitors have varied from Fb (box tuning frequencies) ranging from 60Hz down to 15Hz, a three octave range.
Most of the "resonant effect" of a BR occurs over a 1/3 octave range above Fb, response below Fb is for the most part useless. Engineers that have relied on BR for monitoring do not have an accurate or exact representation of the recording below about 1/3 octave above Fb. The lack of accurate LF range accounts for much of the huge variance in response one can hear in the LF of recordings.
Sealed headphones used for LF monitoring may have useful response down to below 8Hz, (two octaves below the Low B on your bass).
Mastering engineers often use sealed subwoofers.
Underwater whale sounds extend from ~7Hz to past 30kHz.
I rapidly get nauseous when exposed to sustained low frequency below ~25Hz at SPL over 80dB SPL, it can take over 15 minutes for my gut to recover.
The last whale watching trip I was on (a few months ago) a good (bad?) portion of the tourists became sea-sick.
I was on the verge of loosing my breakfast myself, add in a little VLF and I'd have been leaning over the rail.
Slapped bass output can go down lower than whale song.
This real time capture of a passive magnetic pickup Yamaha 4 string (normal tuning, low E 41Hz) took me only a few attempts, 2Hz amplitude is higher than 100Hz:
If you want to "truly" reproduce that at porch party levels, your (sealed) bass bin monitor is going to be large, heavy, and use a lot of power. Without a HP, you can watch the cones flop around like a fish out of water.
If you want to make a five string bass sound good using BR, a 32Hz Fb and a steep HP at 25Hz will "get er done".
Or use sealed 10" (2 per chamber) like bass players have since 1969...
Anyway, if you don't have big roadies and trucks to haul your gear, compromises have to be made, BR is one of them.
Art
Last edited:
Much to think about Art
I am surprised to hear how your body responds to LF. I must say that since I only listen to music that has the electric bass or synth bass, I haven’t really been exposed to subsonic too much but the Low B seem to be totally subsonic as in perception through the body and not just ears
But I have been present during sweeps at one of the larger installers and noticed pleasurable sensations only but the sweeps we not under 20Hz and the driver only a single 10w7 off my JL 1000/1 amp
This was set at 30Hz high pass as final tuning and left as since
Re bass bins. My personal needs prolly start with a high 90 dBs base response with a good headroom above that for thumbed bass. THX seem about right but my system has an embedded DSP compressor so cant be totally sure exactly how the thumbed peaks are being handled
How does this compare with industry for a bass bin starting size?
I am surprised to hear how your body responds to LF. I must say that since I only listen to music that has the electric bass or synth bass, I haven’t really been exposed to subsonic too much but the Low B seem to be totally subsonic as in perception through the body and not just ears
But I have been present during sweeps at one of the larger installers and noticed pleasurable sensations only but the sweeps we not under 20Hz and the driver only a single 10w7 off my JL 1000/1 amp
This was set at 30Hz high pass as final tuning and left as since
Re bass bins. My personal needs prolly start with a high 90 dBs base response with a good headroom above that for thumbed bass. THX seem about right but my system has an embedded DSP compressor so cant be totally sure exactly how the thumbed peaks are being handled
How does this compare with industry for a bass bin starting size?
Most of what you hear/feel from the low B on a typical bass is an octave higher, 64Hz.
At high SPL levels sound can be felt in various parts of the body well above 1000 Hz.
Big difference between 30 Hz and 20Hz output level potential (about 7dB for sealed enclosures), and between a sweep and a sustained level.
Huge difference between a car installation and outdoors- could amount to over 15dB.
At 30Hz, the JL10w7 could be anywhere from 120dB to 135dB+ in a car.
Test it if you want to know what the DSP does.
If you measure, make sure you are reading the fundamental, rather than harmonics.
I doubt your Logitech z623 could hit 90dB at 32Hz at 1 meter outside, at best 65dB (inaudible) at 20Hz.
"Bass bin" is just a name with no actual size.
The usual PA industry bass bin was around 22.5" x 45" x 45", ~26 cubic feet, ~735L.
Half or 1/4 that size might be considered a "starting size".
Josh Ricci has tested tons of bass bins of all sorts outdoors- the readings are at 2meters, so add +6dB to them for the usual 1meter ground plane equivalent:
Comparing your Logitech z623 to most of those bins is like comparing a breath to a wind storm.
Art
Last edited:
Art, there may be some confusion. Meeting the z623s output was the subject of the 6.5" driver based project
Let's make some true, undeniable, no grey area, no dependencies type reference subwoofers. Virtual ones
And use that
How? Today I was working on our new bass amp. The target is not the Ampeg sound, but rather the favoured sounds of the bassist on most riddims present in reggae that are still being used to record new songs. That's a very different type of setup to the Ampegs. I have been fortunate to be able to easily nail that range of tones produced by the artist and now working to make a new more powerful but still compact cab. I am now able to compare this to the reference subs to see the shape of response that I am dialling in much better. The mini EDM system will also get a compare during development
Re the fundamentals and harmonics, FL Studio makes this one easy with its on-screen shaping of a note. Its form and the resultant response from the speaker
That's a whole another story, let's get back to what makes for a minimum spec true subwoofer for HT and music. And what makes for a minimum spec true live use subwoofer
I have revised the statement of requirements for the virtual reference. Note that this is now flexible with lower end roll off. The numbers are the minimum to meet and better yet bettered
A 30Hz F0 with 85dB attained band wide and with a 20dB reserve headroom from F10 to 300Hz can't help but ensure that the music is well covered and most satellite to floor standers well covered. Group delay under 40, but not sure about phase (what would be a good margin here). Some of this is borrowed from THX. And I suppose that rating attained at listening position would determine overall LF system size
And some tentative minimums for pro (needs work, is based on simple measurements pretending live use 3m from the car boot. Police would be called to any lawn or porch playing these levels)
A 30Hz F0 with 97dB attained band wide and with a 20dB reserve headroom from F10 to 300Hz can't help but ensure that the music is well covered and most satellite to floor standers well covered. Group delay under 40, but not sure about phase (what would be a good margin here). Some of this is borrowed from THX. And I suppose that rating attained at listening position would determine overall LF system size
Last edited:
OK, you want a sub that can do 117 dB from 30 to 300Hz (about 200Hz higher than a sub should play..) in some unspecified environment with no specified distortion limit, and a group delay no more than one cycle at 25 Hz (40ms).
That leaves out ported subs, what did you have in mind to meet your statement of requirements for the virtual reference ?
What is the virtual reference ?
The minimum requirements for a device to be considered a true subwoofer
What are the minimum requirements?
What makes for a true subwoofer?
The 117dB kick peaks measured at 3m outside the boot in the car park sounds very good and loud. Very danceable and still able to say something in the ear of the one dancing on you. I present these levels as a good results for a small floor, and I am asking if this would make for a good starting point for a pro subwoofer
Upper limit? If the term subwoofer refers to what goes below the woofer and not the subsonic operating zone, then why can't such a device carry multiple stage transducers to properly blend with any type of mains or use a driver that sounds sweet all the way up the bass
Group delay? To be honest, I do not have any expertise in the matter to make this call. Simply going by a published statement that 30-50 is to be expected at the lower frequencies and picking the middle for baseline. When the educated types fence sit. Why do you say that about ported? I am seeing good examples of below 40 in WinISD for ported
Distortion? I have been very careful to avoid adding this as a factor. Simply, if it sounds bad then it's not good enough, burn the cab as Dave would and start over. The reference material should be music as test signals, as in the shaped synth kick sweeps instead of single frequency steps or sweeps
I find the accurate amplification of the input signal boring and lifeless. Some distortions makes for a more pleasurable listening experience. Distortion is open to appeal. Would you be surprised that one of my first audio purchase since joining this forum was the Pass H2 to go between the back panel input of the z623 and its front stage? I like the sound of the system with this on and enough volume to hear the port output, it sounds so much more pleasurable. Totally fair that an effected double bass might not be for everyone but goes really with the electric and synth. Maybe the remixer in me loves this. So, distortion is a flavour rather than a factor
Whatever is the best recommended practice for taking a subwoofers measurements would be the reference environment, I am guessing something fairly anechoic. A 3" PC 'sub' going 70Hz to 300Hz measured in this environment, would that qualify as a true subwoofer? Is a 6" placed alongside a 3" FR in stereo pair, a subwoofer? When does a device start being a subwoofer and stop being a subwoofer in the test environment
I am not the right person to make this call. Best I can do is extrapolate from past discussions and standards like the THX. I have pulled out a surmise. Whether it correct or not is not the point. The point is placing that in front of educated types and asking if these would make for some solid goal posts. I think the silence on this demonstrates just how uncertain most folks are themselves, as evidenced by the lack of debate and discussion
Anyone game to jot down an SOR?
30ms is one cycle at 33.3 Hz, 50ms is one cycle at 20 Hz.
Adding a HP filter will increase group delay at frequencies that are removed.
I don't worry about something that is gone.
This is what I've said:
https://www.diyaudio.com/community/...ers-out-of-fashion.412687/page-3#post-7683063
When looked at as an entire system, the bass reflex response may be considered minimum phase, but combined group delay alone does not characterize the separate arrival times of the driver and port output.
The compliance, or ”springiness" of the air inside the enclosure reacts with the air mass in the port in a similar manner as the air in a bottle resonates when a current of air is directed across the opening, exciting it’s Helmholtz resonance.
The Fb (frequency of box tuning) at which the box/port system resonates, is determined by the effective length and cross sectional area of the duct, the volume of the “air spring” in the enclosure, and the speed of sound in air.
Since the driver’s back wave is in opposite polarity with the front wave, this inversion brings the two emissions in phase, although the vent output lags by one wave period.
Above Fb, the back wave of the bass driver’s sound emission through the port is delayed by the “air spring” and inverted in polarity, the first arrival of the port output is delayed 360 degrees from the driver output.
At Fb, the first arrival of the port output is delayed 270 degrees from the driver output.
The “in phase” combination of the delayed port output and the driver’s front wave constructively reinforce each other. The constructive reinforcement produces higher output for a given driver excursion compared to a closed box, or a similar output with less excursion around Fb, which reduces driver distortion around Fb.
The drawback of the resonant reinforcement is time smearing, the vent output augments the driver’s output by adding a "resonant tail" to it.
At Fb, the port’s output is 90 degrees behind the driver’s front radiation, at frequencies below Fb, the vent polarity inversion reverts to 180 degrees, and the out of phase back wave cancels the front, reducing combined output at around 24dB per octave. Below Fb, the driver behaves as though in free air.
The bass reflex time smear drawback vs the requirement of double the sealed drivers and power for similar low frequency SPL is why neither sealed or ported cabinets have ever gone "out of fashion".
https://www.diyaudio.com/community/...ers-out-of-fashion.412687/page-8#post-7684685
Really appreciate the detail STV put into documenting his port research.
50Hz is a nice number to work with, 1000ms/50Hz=20ms being one cycle (360 degrees) duration time, each 90 degrees of phase 5ms.
At Fb (bass reflex tuning frequency) your "hard burst" test clearly shows the first arrival of the port output delayed by 15ms, (270 degrees) from the driver output:
We hear complaints about the amplitude level "ramp up" time of the port and it's decay time, seeing the ported compared to a sealed in this manner shows clearly shows what the static phase and frequency response chart above does not.
Randy, your SOR(s) are your babies, DIY !
Cheers,
Art
Art. Thanks again. Always appreciate you taking the time to explain things. Ports can be hit-and-miss too. One of my fav dubs makes great use of that. Its The Same Dub by Sly and Robbie. On most ported systems built around reggae, this one he makes sound like two different basses having a duet. The 43Hz tuning in my car makes for some sweet port bass. I experienced the same effect on the band pass subs of the Lion Sound System back in the day. We syncopate man. Especially when you start dropping delays and echos between the beat steps. With the right type of music, ports are very musical and it all about music, so no loss.
I think there is a massive cultural difference of sitting back and pretending to be listening live to strings ensemble and the itch to interfere and 'play' the song whether through the mixer, sound system or body movements
THX has proven to be a great guideline for dynamic range.. I think that weighed with your comments in the Cub Sandwich project is a great indicator of dynamic range for small live scenarios. The Outdoor test with the boot open showed that you were right about my max SPLs from that project was a bit quiet. The levels I measured were just around what I need. So yeah an SOR built around THX and with another 12dB or so headroom above THX for sounds about right
I think there is a massive cultural difference of sitting back and pretending to be listening live to strings ensemble and the itch to interfere and 'play' the song whether through the mixer, sound system or body movements
THX has proven to be a great guideline for dynamic range.. I think that weighed with your comments in the Cub Sandwich project is a great indicator of dynamic range for small live scenarios. The Outdoor test with the boot open showed that you were right about my max SPLs from that project was a bit quiet. The levels I measured were just around what I need. So yeah an SOR built around THX and with another 12dB or so headroom above THX for sounds about right
Did you know that the cola bottle was a part of the lineup with composer, musician and singer R.D. Burman? When done right, this way of energising the air in the vessel can sound very beautiful and carries the sounds of air
The drivers that I have picked out for the very small boxes might just love the cab they are in with the back of the port blocked and converting to sealed mode. By the same token, that's a small box with a large displacement driver and a big port, I wonder if the drivers have the breath to play a bass pipe. This seems to hold up when looking at sound systems designed for party, with heavy basslines from an electric bass guitar with the reggae sound systems as a good example
Are these types of things some sort of hybrid of BR and a horn? Or is the BR system playing a port that is a horn? I would really appreciate some help with starting off on setting something up like this that can carry an FB of 43Hz with a decent slow roll off with a driver volume around 35L for the Dub/EDM/HT project
Another one that I am one day hoping to hear is a dual 15" TL playing the Meet The Paragon's album side b. I put away HR after not being able to understand how to enter a driver properly. But messing with the default driver shows a simple math that can done on a drawn graph to calculate a quarter wave pipe and any tapers and segment Sd. I think HR is needed to calculate the results of any taper, but a straight 43Hz pipe should be simple enough? Can I place a dual opposed pair of ZXI15.4Ds a third up from the closed end? And fit the PRO-ZT69 on the top end for a pair of full range floor standing towers with tubes covering down to 80Hz and tube effected class d below that? Would such a project be feasible for home use? I think this combo would easily have great dynamic range for 3x6m room but as we have seen, often wrong
My chaotic ramblings tend to have that effect
I have performed on the two prominent sound systems in Sydney back in the 90s and very aware of the one that needed to have the bass knob turned down from song to song and the other that didn’t
But live use is another story
Lets add to the chaos. I haven’t yet run the Lab12 through the sims. Is this a good sub to use as a reference for comparing traces? Can it hold its own against the smaller ZXI10.4D and the quieter but lower reaching in the same box ZXI12.4D. Can the Lab12 adapt to a small box?
What other main stream drivers can beat up 30Hz and lower with 35L and exceed THX over the sub band
The box is 35L and 23Hz tuning. Blue is the ZXI12.4D and green is the LAB12. The red trace is the ZXI10.4D in 30L and 25Hz tuning. The sims sorta bear out my talks with DS18 about choosing one of their drivers for home HT and music, with the 10" being most highly recommended to me for low, loud and clean in a very small box. There is no boost used and the drivers are at full power. All have 20Hz high pass turned on
Lets see if I am reading this right. The LAB12 suffers a bit in the undersize box. WinISD initially places it in 100L with 22Hz Fb and it does have very awesome low reach with that volume behind it. But at 35L, the ZXIs make better use of the low volume and reach lower with a flatter response. Please pull me up if I am not reading this correctly
Let's see the SPL graph
The drivers are at their respective full powers. That lil 10" is impressing me. That's some serious output from 30L. Which one is subwoofing the most here?
Let's see what the excursion graph says about how hard the drivers are working
The lil 10 is working hard but still well within its limits. Would I be correctly reading this if I conclude that the 10 is responding more to the input signal and converting electrical energy to mechanical therefore acoustic more efficiently?
Here is another interesting one. Lets see the LAB12 with the stated 'program power' whatever that means
The LAB12 seems to exceed xmass over much of the audible low bass to band on 60Hz. This tells me that the program power is drivel. What is that supposed to be good for? I can see an enthusiastic kick just making it but adding a bass guitar note to that kick would toast the driver. Actually the driver in the pics and the response seem a lot like the dual magnet high excursion Response driver that Jaycar introduced back in the heyday of DIY when the car subs were just getting up with the JLs in v1. That driver did doof doof ok, but dub made toast out of it. A similar driver was used in the bandpass subs of the sound system in the cellar club that I once DJ'ed on. On the other had, the other drivers seem to handle peak power with much more composure and not exceeding xmax above Fb
Let's give all of them the LAB12s 800w program power and see the Xmax and SPL graphs to see how efficiently they are converting electrical to mechanical
Given the same power, The LAB12 is more efficient converting higher up towards 50Hz while the 10 is a touch more efficiend towards 30Hz. The ZXI12.4D seems stubborn in comparision but makes up for it by being the least peaky of the trio or the most linear
Thats the output side. Lets see how much group delay
The LAB12 appears to have a very good return here but is this due to being not able to get up in the small box? At about 30Hz and higher, all of them are doing very well
I don't know how to read phase very well. What does it mean for a bench report and what it means for music listening
Now lets look make the LAB12 a bit more comfortable and give it some room to play. The 10" seems like a better all around perfomer when compared to the ZXI12.4D but it will flop around in much larger boxes. Lets do a sim for 60L box for a similar money build. This would pitch two 10s against one LAB12 in the 60L box. Is it unfiar on the solo Lab? Tough, appoint a local outlet and stop asking me to spend an outright almost $800 AUD to source something that looks like might get toasted at higer more sustained dynamics. Just to keep it a bit more fiar will also see how two LAB12s deal with 60L. The black trace is the dual LAB12s in 60L, green is single LAB12 in 60L and red is the dual 10s in 60L
Now one more with the solo LAB12 running 100L vs solo 10 running 30L and dual 10' running 60L. This is to see how much subwoofing can be packed into smaller boxes for folks who don't have space to run large cabs
The 100L LAB12 can now reach its lows, but response wise it's on par with the tiny by comparison 10" in 30L. The single 10 hold its own with output against the LAB12. The dual 10s tell some story though. In a box just over half size of the LAB12, it predicts almost 119dB at 30Hz with a flat response above that
How do this trio define subwoofing? Especially when looked at a domestic acceptability factor. This factor can often mean the difference between a fulfilling and so so listening experience. I know I don't have the space to accommodate the LAB12 in my tiny home, Neither would I want it cluttering the deck of the houseboat
I think I will set the single and dual 10" versions as the reference defining subwoofers in my WinISD workflow. There are other drivers that promise a flat higher SPL but rolling off a bit earlier around 30Hz. Those would actually be the ones actually getting built first and maybe a single 10" reference for PC workstation for video work. It will be good to have these two references for bass out of small cabs open in WinISD when working on any other project
Lets see if I am reading this right. The LAB12 suffers a bit in the undersize box. WinISD initially places it in 100L with 22Hz Fb and it does have very awesome low reach with that volume behind it. But at 35L, the ZXIs make better use of the low volume and reach lower with a flatter response. Please pull me up if I am not reading this correctly
Let's see the SPL graph
The drivers are at their respective full powers. That lil 10" is impressing me. That's some serious output from 30L. Which one is subwoofing the most here?
Let's see what the excursion graph says about how hard the drivers are working
The lil 10 is working hard but still well within its limits. Would I be correctly reading this if I conclude that the 10 is responding more to the input signal and converting electrical energy to mechanical therefore acoustic more efficiently?
Here is another interesting one. Lets see the LAB12 with the stated 'program power' whatever that means
The LAB12 seems to exceed xmass over much of the audible low bass to band on 60Hz. This tells me that the program power is drivel. What is that supposed to be good for? I can see an enthusiastic kick just making it but adding a bass guitar note to that kick would toast the driver. Actually the driver in the pics and the response seem a lot like the dual magnet high excursion Response driver that Jaycar introduced back in the heyday of DIY when the car subs were just getting up with the JLs in v1. That driver did doof doof ok, but dub made toast out of it. A similar driver was used in the bandpass subs of the sound system in the cellar club that I once DJ'ed on. On the other had, the other drivers seem to handle peak power with much more composure and not exceeding xmax above Fb
Let's give all of them the LAB12s 800w program power and see the Xmax and SPL graphs to see how efficiently they are converting electrical to mechanical
Given the same power, The LAB12 is more efficient converting higher up towards 50Hz while the 10 is a touch more efficiend towards 30Hz. The ZXI12.4D seems stubborn in comparision but makes up for it by being the least peaky of the trio or the most linear
Thats the output side. Lets see how much group delay
The LAB12 appears to have a very good return here but is this due to being not able to get up in the small box? At about 30Hz and higher, all of them are doing very well
I don't know how to read phase very well. What does it mean for a bench report and what it means for music listening
Now lets look make the LAB12 a bit more comfortable and give it some room to play. The 10" seems like a better all around perfomer when compared to the ZXI12.4D but it will flop around in much larger boxes. Lets do a sim for 60L box for a similar money build. This would pitch two 10s against one LAB12 in the 60L box. Is it unfiar on the solo Lab? Tough, appoint a local outlet and stop asking me to spend an outright almost $800 AUD to source something that looks like might get toasted at higer more sustained dynamics. Just to keep it a bit more fiar will also see how two LAB12s deal with 60L. The black trace is the dual LAB12s in 60L, green is single LAB12 in 60L and red is the dual 10s in 60L
Now one more with the solo LAB12 running 100L vs solo 10 running 30L and dual 10' running 60L. This is to see how much subwoofing can be packed into smaller boxes for folks who don't have space to run large cabs
The 100L LAB12 can now reach its lows, but response wise it's on par with the tiny by comparison 10" in 30L. The single 10 hold its own with output against the LAB12. The dual 10s tell some story though. In a box just over half size of the LAB12, it predicts almost 119dB at 30Hz with a flat response above that
How do this trio define subwoofing? Especially when looked at a domestic acceptability factor. This factor can often mean the difference between a fulfilling and so so listening experience. I know I don't have the space to accommodate the LAB12 in my tiny home, Neither would I want it cluttering the deck of the houseboat
I think I will set the single and dual 10" versions as the reference defining subwoofers in my WinISD workflow. There are other drivers that promise a flat higher SPL but rolling off a bit earlier around 30Hz. Those would actually be the ones actually getting built first and maybe a single 10" reference for PC workstation for video work. It will be good to have these two references for bass out of small cabs open in WinISD when working on any other project
I think they might be called scoopers or something. Can they be done for high excursion, low Vas drivers that I am messing with for around 33 to 43Hz Fb?
"Scoop" designs are based on the JBL D55/D43 designs from the late 1940s/ early 1950s, named for the horn shape, which resembled a sugar scoop.
The "pro" versions, 4520 dual 15" and 4530 single 15" "rear (back) loaded horn" (BLH) designs were very common in use for reggae systems back in the 1970s, their popularity still continues, and many other BLH designs have been made through the years.
They were typically crossed over to HF horns between 500 and 1200 Hz.
Low end of 42 and 50Hz, and a deep phase cancellation dip ~ 160Hz gave them a particular sound.
BLH designs can be adapted for high excursion, low Vas drivers.
Tapped horn designs are more space efficient than BLH for a given Fb/Fc and output level.
Ratings are good for comparisons to other drivers that also have been evaluated using an EIA 426A noise source and test standard in a free-air, nontemperature-controlled environment.
"Music program" is simply double (+3dB) the EIA 426A RMS rating, 400/800 "watts" for the LAB12.
A driver's impedance in free air is generally much higher on average than it's nominal rating, so the actual power dissipated at a given drive voltage (49 volts for the nominal 6ohm LAB12 driver for "400 watts") is less than in a cabinet.
Around 24 years ago the LAB12 was designed for use in Tom Danley's (Live Audio Board) LAB horn.
Depending on the cabinet design, like any driver, either excursion or thermal limits may be reached first.
The LAB12 thermal and excursion capability are nothing to get excited about today.
Art
Thanks for confirming the type. Maybe a quarter wave resonator based port would add too much size to cab for my transport ability. A 33Hz port on a 30L cab will still be huge, maybe I can create a scoop look by using an exit flare?
Anyway, one more 'subwoofer' sim to run. The ZR12.4D that I recently acquired sims something weird. It's not loud by any means, but transfer function magnitude is very sticky between under 20Hz and 70hz. It just doesn't want to respond away from that zone, and no reasonable changes to box volume or tuning can iron out a hump over the very low bass. Setting Vb = Vas and Fb = Fs makes this low and powerful way out of its 22L box class subwoofer prediction for a solid sub 20Hz output
Again, this would be difficult to keep this wonderful 22L volume and manage a port for it. This one I will build as the workstation monitor sub with dual opposed PRs. Unfortunately, it's proving to be a bit quieter than the reference subs. Much quieter really and worrying that may again not be suitable for my EDM/Dubwoofer
Fortunately I have a 10" that I bought two years ago still unused that sims much louder and flat from 36Hz and up with even just 20L behind it and running a 43Hz tune. I might be able to make my August deadline for a single cab with this driver instead. And the reduced driver volume my even allow something scoopish
Unfortunately, this driver is also unobtanium for me now. I won't be able to do the set of 4 with this model
Fortunately, the 12" version of that is still very obtanium and sim much more performance than the 10 in similar volumes. I will try to secure 4 of these and hope it's a better impulse buy than the ZR12.4D 😀
Ok, so the ZR12.4D and ZXI15.4D sims left to run for the virtual reference stakes
Anyway, one more 'subwoofer' sim to run. The ZR12.4D that I recently acquired sims something weird. It's not loud by any means, but transfer function magnitude is very sticky between under 20Hz and 70hz. It just doesn't want to respond away from that zone, and no reasonable changes to box volume or tuning can iron out a hump over the very low bass. Setting Vb = Vas and Fb = Fs makes this low and powerful way out of its 22L box class subwoofer prediction for a solid sub 20Hz output
Again, this would be difficult to keep this wonderful 22L volume and manage a port for it. This one I will build as the workstation monitor sub with dual opposed PRs. Unfortunately, it's proving to be a bit quieter than the reference subs. Much quieter really and worrying that may again not be suitable for my EDM/Dubwoofer
Fortunately I have a 10" that I bought two years ago still unused that sims much louder and flat from 36Hz and up with even just 20L behind it and running a 43Hz tune. I might be able to make my August deadline for a single cab with this driver instead. And the reduced driver volume my even allow something scoopish
Unfortunately, this driver is also unobtanium for me now. I won't be able to do the set of 4 with this model
Fortunately, the 12" version of that is still very obtanium and sim much more performance than the 10 in similar volumes. I will try to secure 4 of these and hope it's a better impulse buy than the ZR12.4D 😀
Ok, so the ZR12.4D and ZXI15.4D sims left to run for the virtual reference stakes
Here is the single ZR12.4D vs the two virtual reference created so far. All are at full power and no Eq, A high pass is on. The ZR12.4D seems so much quieter in comparison to the single 10" virtual reference, which is running the same power. Maybe a higher sound quality would save it? Wouldn't know until a real project is made out of it. Maybe I should place it in the 'development' bin together with its smaller brethren, the ZR6.4Ds
You can reduce the volume occupied by the port using curved inner and outer flares, as described in #9 of this thread:
https://www.diyaudio.com/community/...h-push-slot-loaded-build.409197/#post-7602789
That said, if you want to tune low and keep the box size to a minimum, passive radiators are the solution
Thanks for the tip Art. I can't help but wonder if a rectangular cross-section with those twin flares can be folded in half without suffering?
Also, am I reading the larger ZR correctly as being too quiet for a 12"?
To all the sub enthusiasts in general, are there any other drivers that can play better than the two red traces in 30L and 60L? I think the last time I posted a sim on one of the Ultimax and asked for help reading the graphs, it was said that the driver appeared to be out of sorts at full power. I am going to run a sim on the ZXI15.4D next to see what it can do against my two virtual reference
Are the dynamics of a single 15" in 60L better than dual 10" in 60L?
What do you mean by "dynamics"?
Simplified and considering eventual equalizing and unlimited power the max output is just limited by displacement, thus Sd*Xmax*number of drivers.