All good man, I could have done with a heads-up about the setting error but since no one is obligated to correct, I hold no grudges
Perth is like further away then some other countries. I have never been more than 3hrs drive west from the east coast!
The answer to chuffing is to decrease the air particle velocity at the port outlet. How you choose to do that I leave to you.
Port resonance
The Holden VF3 V8 and the Lexus LC500 bi-modal exhausts are musical in the loud setting and quiet in the quieter one. I bet those guys know a thing or too about taming it
The Holden VF3 V8 and the Lexus LC500 bi-modal exhausts are musical in the loud setting and quiet in the quieter one. I bet those guys know a thing or too about taming it
All features available in Hornresp are documented in the Help file. It is updated every time a new version of the program is released.
Any other takers? Shall I call this cab a TL or BR moving forward?
I have two box builds planned for this driver. This HT soundbar for our place and a 43hz tune box for a music sub for foam construction tech that I would like to share with the forum
I have two box builds planned for this driver. This HT soundbar for our place and a 43hz tune box for a music sub for foam construction tech that I would like to share with the forum
Did you consider that no one noticed? It's not as if Dave thought, 'hmmm, that's wrong but I'm not telling him!'. 😉
When I discovered the settings error, I thought everyone know all along that I hadn't flipped the switch, and having a bit of a chuckle watching me trying to fit 4 different faces to 3 different cross-section. All it needed was a, "oi, did you change HR to stepped segments?". It was only on noticing the red labelling on David's screenshot that let me catch the error there and start working. Look back, all the responses to the question mention modelling and further reading
About that, scroll wheel just doesn't work on the help file, so I assumed an issue and couldn't do any further reading 😀 . There is a tutorial on using HR that I used and it didn't mention that function. I could never make the tutorial work as I would always get stuck at that point. It's there if you look through this category. Multipage long and no mention of this issue and full of arguments. I thought I would try to bring this up again in this thread and then just give up on HR if no one helped understand as I just couldn't resolve that most basic of problem and tune by ear and instruments
Randy, port chuffing is an airspeed and I think, unscientifically I might add, a laminar flow issue. You don’t always hear it because of the SPL’s involved. The first time I heard it was on a pair of Infinity speakers I owned in college (I am mid fifties now). It was when I put a 5Hz signal on speakers that probably went to 50 Hz, at full excursion. The general rule to avoid it is keep your ports to no smaller than half of the driver area. But as with all rules, there are exceptions. What if the driver Xmax is 2 instead of 20? That’s a factor of 10 and this noise is dependent on air volume so that rule of thumb could be off by an order of magnitude. It sounds like a phwuph sound.
I say it’s a laminar flow issue because I was just reading some Klipsch literature/ad that they avoid port noise by flaring the internal port - likely more than a modest flare I am thinking. Airfoils, like you are thinking, may actually help the problem. The idea there is to go to high pressure, annd hence high velocity, right at the output of the port where there is nothing for the air to rub against. And this matches another speaker I have that has no chuffing but it has a large port and a smaller final opening.
You probably won’t hear it at max spl because it is a fraction of the overall output. I was just putting my impression that this port was a lot worse than what I have seen in terms of this - just a practical impression.
I hear what you are saying about asking about modelling - I was shut down as well. I am guessing it’s nothing personal because I don’t know these people personally, but I can tell you there are 10 other great people willing to help.
I don’t think you are going to get to 20 Hz with a soundbar with any meaningful output. If you look at the amount of air, and the amount of energy, and the wavelengths, that’s a big ask. Even at low SPL. The biggest issue at low SPL isn’t getting to that wavelength, it is HUMAN perception. You just can’t hear that kind of wavelength at low SPL. At high levels, sure. Think of an elephant grunt or a whale. They almost shake your body and you can hear it. Pipe organs, same deal. Most of our perception is modelled on some curves that were made back almost 100 years ago. I think those loudness curves underestimate the drop off that happens at low levels in our perception. My two cents on that topic and I think you would be better off with a sub near the soundbar. Something with enough headroom to handle those big surprises. You might actually want to look at an ‘exciter’ on the chair you sit in versus putting that kind of energy at low levels in the air.
I say it’s a laminar flow issue because I was just reading some Klipsch literature/ad that they avoid port noise by flaring the internal port - likely more than a modest flare I am thinking. Airfoils, like you are thinking, may actually help the problem. The idea there is to go to high pressure, annd hence high velocity, right at the output of the port where there is nothing for the air to rub against. And this matches another speaker I have that has no chuffing but it has a large port and a smaller final opening.
You probably won’t hear it at max spl because it is a fraction of the overall output. I was just putting my impression that this port was a lot worse than what I have seen in terms of this - just a practical impression.
I hear what you are saying about asking about modelling - I was shut down as well. I am guessing it’s nothing personal because I don’t know these people personally, but I can tell you there are 10 other great people willing to help.
I don’t think you are going to get to 20 Hz with a soundbar with any meaningful output. If you look at the amount of air, and the amount of energy, and the wavelengths, that’s a big ask. Even at low SPL. The biggest issue at low SPL isn’t getting to that wavelength, it is HUMAN perception. You just can’t hear that kind of wavelength at low SPL. At high levels, sure. Think of an elephant grunt or a whale. They almost shake your body and you can hear it. Pipe organs, same deal. Most of our perception is modelled on some curves that were made back almost 100 years ago. I think those loudness curves underestimate the drop off that happens at low levels in our perception. My two cents on that topic and I think you would be better off with a sub near the soundbar. Something with enough headroom to handle those big surprises. You might actually want to look at an ‘exciter’ on the chair you sit in versus putting that kind of energy at low levels in the air.
I think the only thing that can make a chuff sound that you can hear would be flow parting on an edge, whether internal or external. The action is more like lungs than a true pump. The flow is two-way. Can you change the shape of your lips but keep the aperture and keep a brisk air flow and see how the teeth (if you have any left that is) catching the wind and creating a sound, try coughing too
I have subs and space for large ones. I have a 10" driver waiting for cab too. The 20hz attraction is something different. I am no longer a movie sound buff, quite happy with a higher tuning
In Australia, we have something called "wank factor". I would just like a true 20hz ability in the soundbar just so I can say it can do down to 20hz and show a response plot showing so 😀 . Flat on paper and however it rolls off with perception. At low listening levels, a small boost around 40hz is currently set for my 7" "music" sub and playing at 10:33 pm. A highly listenable level, and we can still talk over it. The bass presence is solid, but doesn't extend out of the front door
I'm full of wheezes, chuffs, and whatnot. I should clarify - the 'phwuph' (or 'fwuf') sound will happen at the frequency of the excursion. So for higher frequencies it will end up just being noise. But by then the front speaker and the back port are making something audible.
You could put a dial on it that goes down to 20 Hz. It's a lot like a volume control that goes to 11!
You could put a dial on it that goes down to 20 Hz. It's a lot like a volume control that goes to 11!
Hello all
Please check if I am getting this. In this table representing stepped pipes, the lowest is "thingy" (until there is consensus on whether it's a BR or TL), its pipe lengths are too long, and the problem is pipe resonances. Is this correct, or are there other issues that I am missing?
Are the other two pipes on the table identical to thingy?
If yes, will using the top most pipe with 5 stepped segments fix the resonance issue?
Does the 2m long total pipe have its own pipe resonance problem that can't be fixed by chopping it up?
If Thingy is a BR, using PR will eliminate pipe resonance in a port, as there is no longer a port. Does the remaining driver volume also have pipe resonance? Or is that problem sorted using either the PR or 5 segment TL?
Does this summarise this thread so far?
Please check if I am getting this. In this table representing stepped pipes, the lowest is "thingy" (until there is consensus on whether it's a BR or TL), its pipe lengths are too long, and the problem is pipe resonances. Is this correct, or are there other issues that I am missing?
Are the other two pipes on the table identical to thingy?
If yes, will using the top most pipe with 5 stepped segments fix the resonance issue?
Does the 2m long total pipe have its own pipe resonance problem that can't be fixed by chopping it up?
If Thingy is a BR, using PR will eliminate pipe resonance in a port, as there is no longer a port. Does the remaining driver volume also have pipe resonance? Or is that problem sorted using either the PR or 5 segment TL?
Does this summarise this thread so far?
Enough distractions with the steps. Back to the Thing. We have worked out that the shelf needs to be rebuilt as a desk with a slide out keyboard rest and slide out drawer for fine tools as well as small tool storage. This means that shelf width limit is 900mm and depth is 300mm and height is 320mm. The only thing limiting height is visual access to the very large monitor in the bedroom through a glass window. Very apt for the distant monitor thread. I'll update pics in my DIY Grooveshop thread for the desk
Here is the Thing redone to 900mm width. The design is apparently all the worst that can be put together:
MDF cab material
Box aspect ratio and the length of the port as well as the volumes make it look and model like a bad 2 stepped segments TL. Hornresp file attached
Bad frequency response in HR
Inefficient driver
Pipe resonances
Chuffing
Am I missing anything? On the positive side:
Tiny drivers with tremendous power handling and xmax
Winisd frequency response looks awesome with some EQ down to 20hz. File attached
Guys, please help me learn this a bit with a commentary on the Winisd graphs. To me, they look good but I really am not qualified to claim that. This is with 10db boost at 30hz. What is Winisd saying about this, can the driver take that boost? Is the amp power enough to apply that boost?
This is the Thing as laid out by an online calculator to available shelf area and Winisd
Ready to be cut in MDF. To avoid too much work and keep it to the calculators dimensions, I am keeping it plain. The plan is to give it a look based on sharp, clean edges. Veneered in real birch with some printed trims and an ebony front panel
Pointless having a sub playing by itself, so I have prepared a foam sandwich design for the FR drivers in satellite form. One set of drivers have arrived and just might be enough. I will wall mount these over the sub. Giving them complementary clean hard edges and real wood veneer as well
I hope Erica.C's 150wrms+150wrms FFA001 amp module is not too much amp for them as they only have a 40wrms rating. The sub driver is DVC and the amp for it is the FFA002 with 300wrms+300wrms
Only the sub driver and another set of FR drivers are left to arrive. All the MDF, biax fibreglass, epoxy, fumed silica, real wood veneers and finish I keep on hand
So, through the course of this thread, it's been determined that the cab is a bad TL and even worse BR. Is it worth perusing in this form, or are there better drivers available for 20hz in that space limit?
The sub box in the pics above can also be built from ply or foam sandwich. I am doing it in MDF as I have some that I would like to use up. All the panel size and locations are in the FreeCAD files for the sub, although if it is as bad as has been declared, why would anyone want to build it. It will fit drivers up to 6.5" if you have one that can go low and need a very narrow box
The FR drivers on the other hand, I have prior experience with them, and they are sweet and easy to listen to at moderate volumes and really composed when pushed hard. The sound is similar to low efficiency bookshelf speakers from UK. The driver in question is the ZXI-354 and since they are directed at sound quality competition tuners, they come with full specs unlike usual car drivers
https://ds18.com/cdn/shop/files/ZXI...0-99d4-cd1e8370cefa.pdf?v=9834824496749707254
The cab (Cub) that I designed for foam sandwich is sealed, but the design is flexible and based on my universal template. The height can adjust up or down even after initial assembly, thereby changing the internal volume. It can be turned in a ported or TL, again even after assembly. Any similar or smaller drivers can be fitted using a printed adaptor to fit the designed driver cutout. The FreeCAD file can be used to print, CNC or hand cut the materials. The complete can also be printed to various degrees. All the resources to this and more are in the files
I am making both FreeCAD files available via PM to the forum in appreciation of all the help getting here and enabling me to go further. Support for these CAD files and the build process will be in a build thread once it's been determined if such an animal is worth creating. To be honest, I don't yet have what it takes to make that call and relying on further guidance here
There is a second option. I can do a 6-fold tapered TL for this driver to fit on that shelf too. This box will allow tunnel lengths and SD to be increased or decreased after initial build. This does not have an attached HR file, as I do not know how to sim this. All I have done is simmed a 3 segment in HR and then turned 3 long segments into shorter ones by folding each in half. If any HR buffs would like to have a go, then hit me up for the numbers. Should I ditch the MDF BR box and do a 6 segment TL instead?
Thanks and regards
Randy
Here is the Thing redone to 900mm width. The design is apparently all the worst that can be put together:
MDF cab material
Box aspect ratio and the length of the port as well as the volumes make it look and model like a bad 2 stepped segments TL. Hornresp file attached
Bad frequency response in HR
Inefficient driver
Pipe resonances
Chuffing
Am I missing anything? On the positive side:
Tiny drivers with tremendous power handling and xmax
Winisd frequency response looks awesome with some EQ down to 20hz. File attached
Guys, please help me learn this a bit with a commentary on the Winisd graphs. To me, they look good but I really am not qualified to claim that. This is with 10db boost at 30hz. What is Winisd saying about this, can the driver take that boost? Is the amp power enough to apply that boost?
This is the Thing as laid out by an online calculator to available shelf area and Winisd
Ready to be cut in MDF. To avoid too much work and keep it to the calculators dimensions, I am keeping it plain. The plan is to give it a look based on sharp, clean edges. Veneered in real birch with some printed trims and an ebony front panel
Pointless having a sub playing by itself, so I have prepared a foam sandwich design for the FR drivers in satellite form. One set of drivers have arrived and just might be enough. I will wall mount these over the sub. Giving them complementary clean hard edges and real wood veneer as well
I hope Erica.C's 150wrms+150wrms FFA001 amp module is not too much amp for them as they only have a 40wrms rating. The sub driver is DVC and the amp for it is the FFA002 with 300wrms+300wrms
Only the sub driver and another set of FR drivers are left to arrive. All the MDF, biax fibreglass, epoxy, fumed silica, real wood veneers and finish I keep on hand
So, through the course of this thread, it's been determined that the cab is a bad TL and even worse BR. Is it worth perusing in this form, or are there better drivers available for 20hz in that space limit?
The sub box in the pics above can also be built from ply or foam sandwich. I am doing it in MDF as I have some that I would like to use up. All the panel size and locations are in the FreeCAD files for the sub, although if it is as bad as has been declared, why would anyone want to build it. It will fit drivers up to 6.5" if you have one that can go low and need a very narrow box
The FR drivers on the other hand, I have prior experience with them, and they are sweet and easy to listen to at moderate volumes and really composed when pushed hard. The sound is similar to low efficiency bookshelf speakers from UK. The driver in question is the ZXI-354 and since they are directed at sound quality competition tuners, they come with full specs unlike usual car drivers
https://ds18.com/cdn/shop/files/ZXI...0-99d4-cd1e8370cefa.pdf?v=9834824496749707254
The cab (Cub) that I designed for foam sandwich is sealed, but the design is flexible and based on my universal template. The height can adjust up or down even after initial assembly, thereby changing the internal volume. It can be turned in a ported or TL, again even after assembly. Any similar or smaller drivers can be fitted using a printed adaptor to fit the designed driver cutout. The FreeCAD file can be used to print, CNC or hand cut the materials. The complete can also be printed to various degrees. All the resources to this and more are in the files
I am making both FreeCAD files available via PM to the forum in appreciation of all the help getting here and enabling me to go further. Support for these CAD files and the build process will be in a build thread once it's been determined if such an animal is worth creating. To be honest, I don't yet have what it takes to make that call and relying on further guidance here
There is a second option. I can do a 6-fold tapered TL for this driver to fit on that shelf too. This box will allow tunnel lengths and SD to be increased or decreased after initial build. This does not have an attached HR file, as I do not know how to sim this. All I have done is simmed a 3 segment in HR and then turned 3 long segments into shorter ones by folding each in half. If any HR buffs would like to have a go, then hit me up for the numbers. Should I ditch the MDF BR box and do a 6 segment TL instead?
Thanks and regards
Randy
I did, and research is still ongoing:
https://www.diyaudio.com/community/...-port-resonance-absorbers.388264/post-7522296
Hornresp is a Microsoft Visual Basic 6.0 program, and VB6 does not have in-built support for scrolling using a mouse wheel.
An external Add-in can be loaded to allow mouse wheel scrolling, but this is a complication that I would rather avoid.
Box is ready to cut once my new table saw arrives. Not much else can be done with this one until the rest of the drivers arrive. Another use that I want to put this driver to is a 40hz ported box. There is already a thread about this. I got distracted with wanting to watch all the seasons of SG-1 so had been looking at the soundbar option. I'll sort out a box for that too and get it all ready for cutting
I would really appreciate some help in interpreting what Winisd is saying in the file that I attached. Thanks guys
I would really appreciate some help in interpreting what Winisd is saying in the file that I attached. Thanks guys
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Hi,
Re your WinISD model, a couple of sweeping generalisations:
1: Those are really unusual parameters for any driver - though I can see at least one typo already (Cms simply can't be that high). Are you absolutely sure the rest are all correct? Please post a copy of the datasheet for verification. Also, when inputting parameters, it's best to follow the recommended order of input in the HelpFile to make the model as accurate as possible.
2: Assuming the TS parameters are all correct, you are reeeeeaaallly stretching that driver way beyond what it seems optimised to do. In general, tuning a little bit below Fs isn't normally a massive problem, but here you're trying to stretch over an octave below - that's just too optimistic IMO. Choose a more suitable driver if you're serious about getting any remotely useful output that low.
2a: as a consequence of the above, your underlying, unprocessed response has a significant peak (around 5dB relative to the minimum in-band level) around tuning. That is likely to have audible consequences even when EQ'd. This Thread shows how responses that have more peaking also have more "ringing" or overhang of the output relative to the input, which is a large part of why many people characterise responses that rely on this kind of resonance as "slow" or muddy sounding.
3: Unfortunately, WinISD doesn't update the "driver input power" fields on the Signal tab to take account of the filters. This means that while you thought you were modelling at 600W input, you're actually modelling the response at 600W PLUS the 10dB of gain from your EQ (again, assuming correct TSPs to start with). That means you're effectively modelling at 6000W, which will certainly not be practical. Realistically, this driver just can't be made to do what you're trying to do. Again, choose a driver that's more suitable for your actual goals rather than trying to stretch this one so far from what it's optimised for.
HTH,
David.
Re your WinISD model, a couple of sweeping generalisations:
1: Those are really unusual parameters for any driver - though I can see at least one typo already (Cms simply can't be that high). Are you absolutely sure the rest are all correct? Please post a copy of the datasheet for verification. Also, when inputting parameters, it's best to follow the recommended order of input in the HelpFile to make the model as accurate as possible.
2: Assuming the TS parameters are all correct, you are reeeeeaaallly stretching that driver way beyond what it seems optimised to do. In general, tuning a little bit below Fs isn't normally a massive problem, but here you're trying to stretch over an octave below - that's just too optimistic IMO. Choose a more suitable driver if you're serious about getting any remotely useful output that low.
2a: as a consequence of the above, your underlying, unprocessed response has a significant peak (around 5dB relative to the minimum in-band level) around tuning. That is likely to have audible consequences even when EQ'd. This Thread shows how responses that have more peaking also have more "ringing" or overhang of the output relative to the input, which is a large part of why many people characterise responses that rely on this kind of resonance as "slow" or muddy sounding.
3: Unfortunately, WinISD doesn't update the "driver input power" fields on the Signal tab to take account of the filters. This means that while you thought you were modelling at 600W input, you're actually modelling the response at 600W PLUS the 10dB of gain from your EQ (again, assuming correct TSPs to start with). That means you're effectively modelling at 6000W, which will certainly not be practical. Realistically, this driver just can't be made to do what you're trying to do. Again, choose a driver that's more suitable for your actual goals rather than trying to stretch this one so far from what it's optimised for.
HTH,
David.
OK, and another thing, I just opened your HornResp record to see if the driver parameters there made any more sense, and several are completely different - eg BL is twice the value, Mmd is higher than the Mms in WinISD (it should be the other way round), Le is obviously another huge typo of some kind. On the model side you've also input L34 in mm instead of cm.
The thing is you've got to make sure you're actually modelling with the right data otherwise the modelling, and all the help people are trying to give you, is wasted.
So, please take this as a reinforcement of my earlier request for the Datasheet for the driver?
Cheers,
D.
Edit PS - just so I don't sound too bitchy, there is a potential upside to finding out the parameters might be wrong - if I cherry pick the ones that seem to go together best, the driver is quite a bit more efficient than in your 1st WinISD model, so might be able to get up to 8dB louder while staying at about 600W, instead of "needing" 10x that amount of power.
The thing is you've got to make sure you're actually modelling with the right data otherwise the modelling, and all the help people are trying to give you, is wasted.
So, please take this as a reinforcement of my earlier request for the Datasheet for the driver?
Cheers,
D.
Edit PS - just so I don't sound too bitchy, there is a potential upside to finding out the parameters might be wrong - if I cherry pick the ones that seem to go together best, the driver is quite a bit more efficient than in your 1st WinISD model, so might be able to get up to 8dB louder while staying at about 600W, instead of "needing" 10x that amount of power.
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