The driver sensitivity is stated on the spec sheet as 82dB 1w/1m. Sensitivity is only valid somewhere above Fs, but just a quick "no calculator required" look:
1w=82dB
10w=92dB (+10dB)
100w=102dB (+10dB)
200w=105 (+3dB)
400w=108 (+3dB)
800w=111 (+3dB)
Without going any further, 108-95 (in your sim)= at least 13dB off.
We know that +6dB requires double the excursion, so since the SPL is off by more than 13dB, the excursion figures are also off by more than four times for a given power.
I also know that I can sing or play an acoustic guitar at well over 100dB at one meter, and hitting a toy drum or dropping a spoon will do over 110dB peak.
Obviously the WinISD sim as you presented is off by more than an order of magnitude (10dB) so is not reliable or valid for any decision making.
You didn't specify which of the two variants of the driver you chose to use.
Since you wanted 40Hz response, I figured you would use the ZR6.2D "2+2 OHMS 65Hz" rather than the
ZR6.4D "4+4 OHMS 70Hz" version.
I mentioned before presenting the Hornresp sims in post #15 that I was not 100% certain all the driver TS parameters that could affect "flatness" were correct in my Hornresp simulations, but can say with certainty that the output Spl vs excursion are correct.
That said, the ZR6.2D "2+2 OHMS 65Hz" with in a 6L bass reflex (65Hz Fb) having flat response looks about right.
Output is based on Sd and excursion, without voice coil winding depth and magnetic gap depth I have no idea the validity of Xmax in the specs.
If you have the driver, you could test the validity of the Xmax specification.
Hornresp calculates some of parameters based on TS inputs. Bl, for instance was ~double, which (I think..) is valid for series voice coils. The Le figures could be way off..
Anyway, I make plenty of mistakes, verify my inputs!
Art
I understand you have limited monitor volume size by restricting it to the size of your low height mixer stand.
Since sound drops off at 6dB per doubling of distance, the best way to provide (easily portable) even sound coverage for a small ring of floor seated performers surrounded by a ring of benches would be a central location for an omni- directional monitor.
All the amplification and DSP electronics could still be located under your mixer, but placing the compact bass speaker in the center with an outward-firing ring of small "full range" drivers on top would allow you a much better perspective in mixing.
The Nor275 Hemi Dodecahedron Speaker could give you an idea of the concept:
The bi-amp monitor could be connected using a single four conductor Speakon cord.
Using an 8 conductor cord could allow for multiple high and low zone controls.
Although I'm generally not a fan of downward firing drivers due to cone sag, using a single woofer inside the ring of upper drivers would work well up to ~200Hz:
The entire cabinet could be covered with stretchable, breathable fabric (like Spandex) for an organic look:
Anyway, some thinking "outside the box" in the circle could relax some of the constraints you have imposed and open up possibilities for better sound.
Art
Both WinISD and SpeakerBoxLite require the input of the efficiency figure. Does WinISD not take use this data for SPL calculations? SBLite shows around 10db more output
Where did you find out about this WinISD bug? Is this a known issue and how can I get the program to show a correct sim?
The space in the middle needs to be kept clear. I can do a passive slave version of the sub to be placed out of the way in a porch corner
I think I can safely say that the project is in complete disarray, with serious doubts over the validity of the sims. I have serious doubts over whether I am entering the voice coil data correctly and things regarding the Bl. Especially since in this project the dual voice coils aren't connected together
Excerpt from WinISD help file
Art's comments about having to downgrade the SPL response curve to correct for something is also alarming. Is this how everyone is using WinISD? I found this but don't understand it yet. @weltersys, Art, is this what you are talking about?
Excerpt from WinISD help file
To be honest, I don't understand this half(2pi) space thing and need to get a handle on this. I can't find anything about correcting for driver's efficiency rating. I can understand the calculation that he shows, but not the reason for doing it. This is what the help file says about driver efficiency
Excerpt from WinISD help file
Clearly, WinISD is aware of the efficiency, whether entered or calculated. Does the program really not go on to use this when projecting an SPL curve for given input power? I don't think it's likely and after years of reading speaker projects on this forum, I have never come across any mention of manual correction of the SPL graph
This amount of uncertainty basically kills the project unless I can get enough of a handle on WinISD to be confident about the results
Excerpt from WinISD help file
Art's comments about having to downgrade the SPL response curve to correct for something is also alarming. Is this how everyone is using WinISD? I found this but don't understand it yet. @weltersys, Art, is this what you are talking about?
Excerpt from WinISD help file
To be honest, I don't understand this half(2pi) space thing and need to get a handle on this. I can't find anything about correcting for driver's efficiency rating. I can understand the calculation that he shows, but not the reason for doing it. This is what the help file says about driver efficiency
Excerpt from WinISD help file
Clearly, WinISD is aware of the efficiency, whether entered or calculated. Does the program really not go on to use this when projecting an SPL curve for given input power? I don't think it's likely and after years of reading speaker projects on this forum, I have never come across any mention of manual correction of the SPL graph
This amount of uncertainty basically kills the project unless I can get enough of a handle on WinISD to be confident about the results
I don't know of any bugs in WinISD, and don't use it so can't help you correct your simulation.
The output not agreeing with the sensitivity and power clearly point to improper data entry.
If each coil is connected to a separate side of an amp driven with the same signal, they are basically in parallel.
If only one coil is used, efficiency drops, but not by over 13dB.
A huge incongruity in the SPL should set off an alarm that something is wrong!
Since WinsISD assumes half space (2pi) radiation, and I chose the same in the posted Hornresp sims:
the radiation angle is not an issue.
Hornresp allows you to specify the angle of radiation.
Ang=4.0 is free space radiation, no boundaries, like the Sun's radiation into space.
Ang=2.0 is half space radiation, the speaker's radiating surface located on one (infinite) boundary, like on the surface of the (flat..) Earth.
This is the default setting for most simulators (WinISD, etc.)
Ang=1.0 is quarter space radiation, two boundaries.
Ang=0.50 is eighth space radiation, a corner with three boundaries.
Since a typical household room has six boundaries of various reflectivity at various distance, counting on wall or corner gain is generally not advisable.
A speaker radiating into half space that can achieve 92dB 1/w/1meter on axis is 1% efficient at the measured frequency.
Efficiency is not the same as sensitivity, which should be rated at 1/w/1m, but may "not match the marketing SPL value, which is generally somewhat vague" as the WinISD help file notes.
I'd recommend you train your eye to see the relationship between excursion and output, so you can tell when "promising results" are not close to reality.
This tool makes rough estimates easy (though "racetrack" drivers require diameter conversion):
http://www.baudline.com/erik/bass/xmaxer.html
Since a passive radiator puts out almost all the low frequency SPL, it's excursion limits maximum output.
Remember Hofmann's Iron Law: Low, Efficient, Small, pick two.
Your SpeakerBoxLite sim demonstrates Hofmann's Iron Law, but the output level in the low end in the larger boxes could not be achieved, since it far exceeds the PR's 11mm mechanical excursion limit.
The red trace shows ~95dB at 40 Hz, which would be within the PR's 11mm excursion limit:
Best of luck learning whatever programs you choose to use!
Art
Hmmm I dont know Art, Yesterday you raised this point
The driver spec is 82db, and you are saying that the program is showing 96 response and is way off. But that 96 looks to be the output of the loudspeaker, i.e. the new system response with cab and PR gains. Do you mean that if the driver is rated 82dbthen sim with a cab result should also be 82bd? I assumed WinISD was displaying with cab gain so I cant understand why you think the response should be 82db with 1w
I would appreciate if you would clarify this. Do you think you may in error? Should placing the driver in a reflex system cab like the PR system not show around 13db gain
That what you brought up is the reason for the disarray, and I have been trying to find any mentions of this happening in WinISD and failing.
The driver spec is 82db, and you are saying that the program is showing 96 response and is way off. But that 96 looks to be the output of the loudspeaker, i.e. the new system response with cab and PR gains. Do you mean that if the driver is rated 82dbthen sim with a cab result should also be 82bd? I assumed WinISD was displaying with cab gain so I cant understand why you think the response should be 82db with 1w
I would appreciate if you would clarify this. Do you think you may in error? Should placing the driver in a reflex system cab like the PR system not show around 13db gain
It is possible to get gains approaching 13dB in huge horn cabinets with ~50 times the volume of your self-imposed cabinet volume restriction.
In the upper range of a sub where sensitivity figures may be valid, a front loaded cabinet provides no sensitivity gain.
Near Fb, a flat BR or PR alignment could bring the low frequency sensitivity up near the upper nominal sensitivity.
400 watts is a gain increase of 26dB over one watt.
Your sim in post #16 SPL shows a maximum of 95dB SPL output with a "600w input".
A speaker with 82dB 1w/1m sensitivity should put out 95dB (at some frequency..) at 20 watts input.
1w=82dB SPL
10w=92dB SPL (+10dB)
20w=95dB SPL (+3DB)
20 watts is a gain increase of 13dB over one watt.
If your sim was correct, the driver would have lost considerable sensitivity by putting it in a cabinet.
I hope you find this clear.
Art
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Art I am trying to, thanks for trying to explain
Does this mean that I am viewing a comprised SPL and using lots of power to get an Fb of 40hz out of a tiny undersized volume?
In your experience, how bad is the response for a 6L box targeting 40hz? With the current pick of drivers on the market, can a 6L cab actually be expected to do better?
Am I understanding correctly that a best case scenario of cab volume and driver Fs would need to exist for that 95db at 40hz with 20w to happen?
Am I correctly using a tiny high powered driver like the ZR6.4D and applying loads of power to get a flat and usable response out of the 6L
Does this mean that I am viewing a comprised SPL and using lots of power to get an Fb of 40hz out of a tiny undersized volume?
In your experience, how bad is the response for a 6L box targeting 40hz? With the current pick of drivers on the market, can a 6L cab actually be expected to do better?
Am I understanding correctly that a best case scenario of cab volume and driver Fs would need to exist for that 95db at 40hz with 20w to happen?
Am I correctly using a tiny high powered driver like the ZR6.4D and applying loads of power to get a flat and usable response out of the 6L
Got a call from the office saying the SBA 8x5 racer PR is here. While this is an important project for me, it’s not an immediate priority. So I have the time to get the acoustic’s right
Lets get a proper handle on this situation. The ZR6.4D lists 2.7L and is quite a unit. Its magnet just fits through the cutout. What is with it such a low Vas? What can this driver do in very tiny cabs? Is there another driver that can do better than this one?
Time to find out. Lets start the tiny 40s challenge starting at 4L and give the ZR6.4D the first run. First with the SBA racer PR then the dual 6.5” Dayton Reference PRs and finish up with the dual 8” and dual 10” custom PRs
I’ll design a
Lets get a proper handle on this situation. The ZR6.4D lists 2.7L and is quite a unit. Its magnet just fits through the cutout. What is with it such a low Vas? What can this driver do in very tiny cabs? Is there another driver that can do better than this one?
Time to find out. Lets start the tiny 40s challenge starting at 4L and give the ZR6.4D the first run. First with the SBA racer PR then the dual 6.5” Dayton Reference PRs and finish up with the dual 8” and dual 10” custom PRs
I’ll design a
Having another go at this. I think the data entry is correct
https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/sbacoustics/SB20PFCR-00.pdf
This is dual 8" PR from SBA. I ran a lot of sims with SBA and Dayton PR units from 6.5" to 10". This was the best result overall. Seem to like light duty type PRs with 200 to 250g added. The heavy type of PR drivers didn't do so well as the starting weight seemed too high. 20w gives a peak of 90db so losing output maybe due to tuning well below driver Fs
@weltersys, Art, am I starting to get it right?
https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/sbacoustics/SB20PFCR-00.pdf
This is dual 8" PR from SBA. I ran a lot of sims with SBA and Dayton PR units from 6.5" to 10". This was the best result overall. Seem to like light duty type PRs with 200 to 250g added. The heavy type of PR drivers didn't do so well as the starting weight seemed too high. 20w gives a peak of 90db so losing output maybe due to tuning well below driver Fs
@weltersys, Art, am I starting to get it right?
250 grams added seems like a lot, have you checked with SBA as to the maximum recommended added mass?
Seems like you entered most data correctly, but you missed entering the Le, which is listed as 461.9m mH.
That Le might be 4.62mH, or 0.46mH, I'm not sure the order of magnitude reduction.
In any case, Le acts like a series coil in a crossover, and rolls off some of the high end.
Sd was listed as 143Cm2 on the specs linked in post one, you entered 143.7, not much different, but odd.
The Znom was entered as "6" ohm, should be 8 ohm for series connection (selected), or 2 ohms for parallel connection.
From what I've read, using the Voicecoils "2" Connection "Series"
may cause the Bl and Re parameters to change when changing the connection wiring from parallel to series.
Be sure to monitor these when changing the connection option, WinISD should automatically change those values properly.
That said, the ZR6.4D's TS parameters are for Re...3.4 + 3.4 ohm (=6.8), I think 6.8 ohms should have been entered rather than 3.4 ohms
This could account for the ~5dB loss in sensitivity compared to the ZR6.4D's 82dB specification.
A "one watt" voltage should be ~1.4v for 2 ohms, 2v for 4 ohms or 2.83 for 8 ohm nominal series connection.
Can't tell what was modeled without seeing the impedance graph, but it should have a minima near 6.8 ohms, not 3.4ohms.
I'm guessing it will read wrong.
The left hand data is cut off on all your screen shots, no idea what this is-
Looks like it could be (too much..) PR excursion from another sim.
Anyway, the excursion vs SPL looks close to what I'd expect, but the response curve will change when you correct the Re input.
Looks like it will take ~600 watts without hitting Xmech on the PRs.
Art
Ok cool. Thanks for helping me get a handle on this. WinISD has a help file, but it has typing and consistency errors. I'll try to correct the entered data
file:///C:/ProgramData/winisd/help/usingwinisd/newdriver.html
In the suggested data entry procedure. Entering the Le is not mentioned
But! In the following part they mention entering it
That's one correction. WinISD allows changing how it's entered. You are correct about the voice coil confusion. The author of the help file seems aware of this confusion and its badly composed. Can I treat this as a single coil and just enter 6.8R and 1 coil. From the wording of the help file, I assumed that its asking for Re for a single coil as well as the number and connection to internally determine running Re. So after entering the BL and 3.4 as Re, I set coils as 2 and connections as series. This changed the Bl and Re so then changed them back to 6.53 and 3.4
That's the second corrections. I'll enter that to display 6.53 for Le and 6.8 for Re with 2 voice coils and series connection displayed.
Good pickup! Will check this out and post updated results, including the imp graph. i am guessing this is the solution for 'deconfusing' this issue
Ah, that's the group delay for the system with those installed tuning weights. Doesn't look too bad to my untrained eye. I have noticed higher in other sims. I should include the titular info
Art, here is the thing about WinISD. In the box tab there is a drawing of a mounted driver. Clicking on this and then bringing up one of the graphs lets one perform a trick that the author of the help file seems rightly proud off. Let's say I have the frequency response graph up. By clicking, dragging and dropping imaginary points within the box, I can shape the curve to a desired response. Then I can check to see auto changes to the tuning setting being the Vb and PR tuning weight. These change as you shape the curve. The cursor can be picked up and dropped within that drawing multiple times to adjust the curve in different directions. It just works. I would have never thought to run tuning weights more than 80g, but the shaping can auto add as much as it needs to get the response. Works with any graphs and I did it with the group delay to get it as low as possible while keeping desirable curves in other graphs and Vb.
I found this, using other PR with higher xmax like the 10" SBA's can get me the same curves and Vb but with much more weights, up to 400g in the case of the 10" NRX PR. Putting all the SBA and Dayton PR units through the paces showed that best performance including group delay was with either 2x 5x8" racers or 2x 8" PFCR racers which have a very low moving mass around 70g when compared to all the other series of PRs They also have lower Vas numbers. These two PRs seem to be more designed for woofers in multiway rather than subs. Could it be these lighter cones and softer suspensions and lower Vas which lets these work with the 'not very subwoofer but very superwoofer' ZR6.4D? I hope I am getting a grasp of this
There are some more PRs like this on Ali, softer woofer types in 8 and 10". They do not include any parameter's data. I can measure Xmech, Sd and Mms (cheap enough to take one apart and weigh the moving parts). Any tips on how to extract the Vas, Fs and Qms? Then I can sim them up too
I am not ready to give up on this driver but!
There is a need for more output. Not all porch functions are on the solemn side. It's mostly celebration and often a wider audience in a larger temp shelter on the lawn. I think I will also push the physical constraints as much as I can and mess a bit with a higher seated stand. Maybe I can raise it another 100mm or so. This will give me enough panel to mount the ZR12.4D and the relevant PRs for it. That driver has a Vas of 22.7L and Fs is 28hz. That's pretty much the upsized base body volume. Getting to tune that up to 40hz should be more like 'detuning' and allow me to reclaim enough electronic bay space. I am guessing that by detuning it, there would be other benefits such as flatter group delay
Am I grasping the situation correctly? There is no rush for completion on any of these as they are something that I would like to replace existing stuff with and not looking to fill any critically missing gear
@weltersys. Art, thanks again for your time and paitence
file:///C:/ProgramData/winisd/help/usingwinisd/newdriver.html
In the suggested data entry procedure. Entering the Le is not mentioned
But! In the following part they mention entering it
That's one correction. WinISD allows changing how it's entered. You are correct about the voice coil confusion. The author of the help file seems aware of this confusion and its badly composed. Can I treat this as a single coil and just enter 6.8R and 1 coil. From the wording of the help file, I assumed that its asking for Re for a single coil as well as the number and connection to internally determine running Re. So after entering the BL and 3.4 as Re, I set coils as 2 and connections as series. This changed the Bl and Re so then changed them back to 6.53 and 3.4
That's the second corrections. I'll enter that to display 6.53 for Le and 6.8 for Re with 2 voice coils and series connection displayed.
Good pickup! Will check this out and post updated results, including the imp graph. i am guessing this is the solution for 'deconfusing' this issue
Thanks for picking that up too. It's in blue text, so auto calculated. That's the third correction to do. The author mentions this correction, but I missed it
The left hand data is cut off on all your screen shots, no idea what this is-
Looks like it could be (too much..) PR excursion from another sim.
Ah, that's the group delay for the system with those installed tuning weights. Doesn't look too bad to my untrained eye. I have noticed higher in other sims. I should include the titular info
Art, here is the thing about WinISD. In the box tab there is a drawing of a mounted driver. Clicking on this and then bringing up one of the graphs lets one perform a trick that the author of the help file seems rightly proud off. Let's say I have the frequency response graph up. By clicking, dragging and dropping imaginary points within the box, I can shape the curve to a desired response. Then I can check to see auto changes to the tuning setting being the Vb and PR tuning weight. These change as you shape the curve. The cursor can be picked up and dropped within that drawing multiple times to adjust the curve in different directions. It just works. I would have never thought to run tuning weights more than 80g, but the shaping can auto add as much as it needs to get the response. Works with any graphs and I did it with the group delay to get it as low as possible while keeping desirable curves in other graphs and Vb.
I found this, using other PR with higher xmax like the 10" SBA's can get me the same curves and Vb but with much more weights, up to 400g in the case of the 10" NRX PR. Putting all the SBA and Dayton PR units through the paces showed that best performance including group delay was with either 2x 5x8" racers or 2x 8" PFCR racers which have a very low moving mass around 70g when compared to all the other series of PRs They also have lower Vas numbers. These two PRs seem to be more designed for woofers in multiway rather than subs. Could it be these lighter cones and softer suspensions and lower Vas which lets these work with the 'not very subwoofer but very superwoofer' ZR6.4D? I hope I am getting a grasp of this
There are some more PRs like this on Ali, softer woofer types in 8 and 10". They do not include any parameter's data. I can measure Xmech, Sd and Mms (cheap enough to take one apart and weigh the moving parts). Any tips on how to extract the Vas, Fs and Qms? Then I can sim them up too
I am not ready to give up on this driver but!
There is a need for more output. Not all porch functions are on the solemn side. It's mostly celebration and often a wider audience in a larger temp shelter on the lawn. I think I will also push the physical constraints as much as I can and mess a bit with a higher seated stand. Maybe I can raise it another 100mm or so. This will give me enough panel to mount the ZR12.4D and the relevant PRs for it. That driver has a Vas of 22.7L and Fs is 28hz. That's pretty much the upsized base body volume. Getting to tune that up to 40hz should be more like 'detuning' and allow me to reclaim enough electronic bay space. I am guessing that by detuning it, there would be other benefits such as flatter group delay
Am I grasping the situation correctly? There is no rush for completion on any of these as they are something that I would like to replace existing stuff with and not looking to fill any critically missing gear
@weltersys. Art, thanks again for your time and paitence
This answers some questions about working with Ali and custom PR solutions. I think I can handle the maths
https://sbacoustics.com/wp-content/uploads/2018/05/Adding-mass-to-passive-radiator.pdf
https://sbacoustics.com/wp-content/uploads/2018/05/Adding-mass-to-passive-radiator.pdf
Well no offense
But it is a 6.5 inch speaker with dual 2 ohm coils.
So the impedance is already big energy sucker.
Basically its a 4 layer voice coil and normally just plain
old series for 4 ohms.
typically efficiency for 4 ohm drivers actually usually worse
than 8 ohms. Not getting " more" power
its using more power to make less output.
" DVC" is just a tapped 4 ohm coil
Its only 82 dB which is rather low.
600 watts is nonsense peak power
300 watts is actual thermal rating.
Normal operation be 20% at most of that
But regardless 600 watts? into a 6.5"
for only 95 dB and Fs is 65 Hz ?
= no bass city
Peak is peak its not RMS and not realistic operating
range.
Its literally a udder waste of time and efficiency
and rather poor Fs.
Sounds very negative I know.
just a not very good speaker.
For porch partys or performance.
95 dB at 600 watts
Some speakers gladly do so with 30 watts.
And good range of 8" speakers closer to 40 Hz even 30 Hz Fs
and normal 8 ohms
Mr WhiteDragon
Thank you and let's start with this, no offence taken and there is no argument. I think you are a pro but regardless, you are right. Please see this as evidence of you being very correct
Now please let me bring you up to speed as I would not expect you to glean much useful from my ramblings, self musings and doubts
Let me try to speak as a pro from another field, and please excuse any misconceptions
Statement of requirements (SOR)
Replace current kick and electric bass monitor for a 3m circle of performers seated on their bums on the floor. The current one is a 7" in a cab that is too tall at 30cm
If there is any audience, they would be seated on the same mat which is usually max 3m x 5m
Fit under the floor mixer stand (Roland MX1 18 channel digital mixer with effects sequencer), so physical constraints are max 400mm x 300mm x 200mm for external max cab size
Fit into a third of that cab volume, the other two thirds taken up with electronics and cab structure, so working driver volume is around 6L preferred
No clutter, minimum loose cables, everything contained within the circle with the only blocky things being the instruments with the largest being the harmonium and dholak
Aesthetics, presentation and ergonomics are very important. Nothing in circle apart from mic stands and cables. Not a place for amp cab stacks of the usual style and not a place for regular PA
Note
Clean power and DSP is very affordable so no limits on the electronics
Driver is 4R+4R version, not the 2R+2R version that PE carries
Options?
I spent over 15 months researching drivers. Not many options for useable 40hz out of 6L. Maybe my untrained sims missed some, but I couldn't get anything listed in PE to produce anything useful out of that 6L. An installer friend who works on bus and other large vehicles and fleets tipped me onto this superwoofer driver that is derivative of the ZR6 and mentioned that I should give it a serious go as he has got it to work as a woofer in volumes down to 4L
Any other options for monitor clarity 40hz out of 6L that can beat the 96db of the ZR6.4D as off the most current sims, those updating though as there were still some data entry issues. I have run the corrected sims but haven't had a chance to post details, but I do have a shot of the corrected SPL response. I'll jump at any chance for bettering this 101db at 40hz
I am glad that you also stepped in as well, as this project is as much about showcasing my developments in porting race boat construction tech to speaker cabs for DIY'ers. Would really appreciate some driver suggestions that can tick off the SOR. In your experience, apart from the ZXI6.4D (almost impossible to get when I settled on trying out the ZR6.4D)
A real working model is better for what I am trying to do, and thanks again for your input
Regards
Randy
Thank you and let's start with this, no offence taken and there is no argument. I think you are a pro but regardless, you are right. Please see this as evidence of you being very correct
Now please let me bring you up to speed as I would not expect you to glean much useful from my ramblings, self musings and doubts
Let me try to speak as a pro from another field, and please excuse any misconceptions
Statement of requirements (SOR)
Replace current kick and electric bass monitor for a 3m circle of performers seated on their bums on the floor. The current one is a 7" in a cab that is too tall at 30cm
If there is any audience, they would be seated on the same mat which is usually max 3m x 5m
Fit under the floor mixer stand (Roland MX1 18 channel digital mixer with effects sequencer), so physical constraints are max 400mm x 300mm x 200mm for external max cab size
Fit into a third of that cab volume, the other two thirds taken up with electronics and cab structure, so working driver volume is around 6L preferred
No clutter, minimum loose cables, everything contained within the circle with the only blocky things being the instruments with the largest being the harmonium and dholak
Aesthetics, presentation and ergonomics are very important. Nothing in circle apart from mic stands and cables. Not a place for amp cab stacks of the usual style and not a place for regular PA
Note
Clean power and DSP is very affordable so no limits on the electronics
Driver is 4R+4R version, not the 2R+2R version that PE carries
Options?
I spent over 15 months researching drivers. Not many options for useable 40hz out of 6L. Maybe my untrained sims missed some, but I couldn't get anything listed in PE to produce anything useful out of that 6L. An installer friend who works on bus and other large vehicles and fleets tipped me onto this superwoofer driver that is derivative of the ZR6 and mentioned that I should give it a serious go as he has got it to work as a woofer in volumes down to 4L
Any other options for monitor clarity 40hz out of 6L that can beat the 96db of the ZR6.4D as off the most current sims, those updating though as there were still some data entry issues. I have run the corrected sims but haven't had a chance to post details, but I do have a shot of the corrected SPL response. I'll jump at any chance for bettering this 101db at 40hz
I am glad that you also stepped in as well, as this project is as much about showcasing my developments in porting race boat construction tech to speaker cabs for DIY'ers. Would really appreciate some driver suggestions that can tick off the SOR. In your experience, apart from the ZXI6.4D (almost impossible to get when I settled on trying out the ZR6.4D)
A real working model is better for what I am trying to do, and thanks again for your input
Regards
Randy
That is what the ZR6.4D's TS parameters have been measured as, 6.8R, the series resistance of Re...3.4 + 3.4 ohm.
A change would be expected since the TS parameters (including BL) were derived with a RE of 6.8.
The TS parameters would change from the specs if the coils were in parallel, 3.4/2=1.7 ohms.
The TS parameters would also change if only one of the 3.4R coils were to be used. Dragging the weight of an unused coil lowers sensitivity.
BL would not be 6.53 if the rest of the TS parameters were correct and the Re was cut in half to 3.4...
When the upper 1/w sensitivity comes in near 82dB, you probably have the correct parameters entered
Art, I ran some new sims. I think the data entry is corrected now. Will post these later. For now, the very shallow peak is 77db at 1w. May this be due to going for a flat response to 40hz? Just to check things out, will run a sim targeting 70hz tuning to see if it peaks higher closer to 82dbWhen the upper 1/w sensitivity comes in near 82dB, you probably have the correct parameters entered
When the upper 1/w sensitivity comes in near 82dB, you probably have the correct parameters entered
Results of trying to tune higher than driver Fs as a test to see if trying for a tune well below driver Fs is costing efficiency
82db peak at 90hz, 3db down at 70hz on the low side and 3db down at 145 on the high side, can that be considered fairly flat 74hz tuning? I am guessing it's nailing the 82db rating now? Data entry remains the same since last update. The impedance curve sits on 6.8R on the very flat bits but out of the working range of the 74hz sim. Box size drops slightly for a flat tune. Will do an "Unch it" sim to see how much it can peak with a reasonable hump with 1w
87db at 1w at 90hz. That's up 5db from the flattish high tune in the previous pic. Will try both settings at 300w next
300w, 107db for a flattish 74hz retune 110db
600w, flattish 74hz retune
@weltersys. Art, I am guessing that the driver is working reasonably well within its design range of 70hz to 160hz given my untrained efforts at sims but at last correct data entry. May I please lean on your experience and knowledge to confirm this so I may carry on with some confidence on trying to extract a decent 40hz from it in my 6L?
Guys, would really appreciate suggestions of drivers that can provide a louder clean spl flat down to 40hz than this ZR6.4D in a 6L working volume. I am trying to nail 40hz at 0, not -3
Looks a little humpy, but the an Fb above Fs will do that.
A "flat" tuning would also result in equal level impedance peaks either side of the minima at Fb.
You could get decent response at 40Hz in an undersized box, but it won't be "flat".
Again, remember Hofmann's Iron Law: Low, Efficient, Small, pick two.
For "flat" response down to 40Hz in 6L look for a driver with an Fs lower than 40Hz (~34Hz), and Vas ~1.41 times 6L, ~8.46L. Look at GM's posts and see if I got that right
That said, you have a digital mixer that probably has parametric EQ, you can adjust the speaker's response for whatever you like.
Art