I think based on your $$$ discussion already the current design will meet your current needs.
I think its unfair to you for others to trivialize the need for proper bass and I just want to make sure you are aware of the potential issues that is all.
I think its unfair to you for others to trivialize the need for proper bass and I just want to make sure you are aware of the potential issues that is all.
Hi Doug,
Now why the retreat?
You have been banging on endlessly abut how the system will completely suck if not done your way.
Leo ASKS YOU for your way and you post this!?
You could at least suggest some cheap Sub-Projects that will add serious bottom end to the Peaveys, plus buying an inexpensive passive cooled Pro-Amp and adding analog bass management in the receivers Tape loop (if it has such.
Come on self proclaimed expert, suggest something that makes sense to Leo (if you don't, I will, as a possible next stage), surely you can be at least THAT constructive, given how much electronic ink you spilled in this thread!
Ciao T
Now why the retreat?
You have been banging on endlessly abut how the system will completely suck if not done your way.
Leo ASKS YOU for your way and you post this!?
You could at least suggest some cheap Sub-Projects that will add serious bottom end to the Peaveys, plus buying an inexpensive passive cooled Pro-Amp and adding analog bass management in the receivers Tape loop (if it has such.
Come on self proclaimed expert, suggest something that makes sense to Leo (if you don't, I will, as a possible next stage), surely you can be at least THAT constructive, given how much electronic ink you spilled in this thread!
Ciao T
I never once posted I was an expert and I not sure how this is a retreat.
He already posted he does not have the money to get an AVR with bass management right now. That means he does not have $200 to add to the project so how is suggesting adding more drivers going to help either?
Im just posting to make sure he realizes some of the compromises with the current design.
He already posted he does not have the money to get an AVR with bass management right now. That means he does not have $200 to add to the project so how is suggesting adding more drivers going to help either?
Im just posting to make sure he realizes some of the compromises with the current design.
Hi,
That is a different question. A whole track contains more than Kick Drum.
I spend enough during sound checks staring at the 3rd octave RTA while adjusting the drumkit channels on the mixer to know which bands "wriggle". And it sure ain't 50Hz. I doubt even classical Kettle Drums (which are much larger than kick drums) have that low a fundamental resonance.
Let me prepare a few samples of recordings of only the drums, then you can see what frequencies ping up on the RTA.
Now for a whole track including E-Bass and Syth Bass for pop-music I agree with the 50-80Hz.
22...24" Kick Drums for (hard) rock. Arguably most drummers there tend to have the skins quite tight, which shifts up the resonance. Jazz would actually be lower.
But we are talking about real drums, not synthesized drums.
Actually, a stereo pair of speakers with music (which is usually mixed mono compatible, so much of the signal is correlated) will produce around 98dB with 1Watt RMS per speakers at 1m.
In an open field we find as we double our distance we loose 6dB SPL, unless we use highly directional (so called "long throw") systems. In a room it is not as easy. An easy rule of the thumb is to add an extra 2dB to the freefield.
So, with 4m listening distance (I'm more at 3m) we have around 10dB attenuation. So we get around 88dB SPL at the listening position for around 1 Watt per channel.
I have spend the occasional concert with a SPL Meter where I normally sit (sad, I know, but I wanted to know. In the 3rd to 5th row average SPL's for large orchestral works rarely exceeded these 88db. The crest factor was never more than 14dB. But I always design my tube amp's to tolerate 6dB
Oh, BTW, are you using your ears to listen? If you do, just be aware that the actual acoustic system in the ear produces around 30% THD at 92dB at the diaphragm. The few % from my speakers and tube Amp pales next to that. Which is probably why they remain inaudible.
30% Distortion - of course you have ears so you are okay with that.
Dear Doug - there are more things between heaven & earth than written about in harman technical papers.
Reality is a wee bit more complex than the two dimensional logic these and similar things employ.
In fact, having a fair bit of distortion of the right kind may be a "good thing" that you are missing 😛.
Ciao T
That is a different question. A whole track contains more than Kick Drum.
I spend enough during sound checks staring at the 3rd octave RTA while adjusting the drumkit channels on the mixer to know which bands "wriggle". And it sure ain't 50Hz. I doubt even classical Kettle Drums (which are much larger than kick drums) have that low a fundamental resonance.
Let me prepare a few samples of recordings of only the drums, then you can see what frequencies ping up on the RTA.
Now for a whole track including E-Bass and Syth Bass for pop-music I agree with the 50-80Hz.
22...24" Kick Drums for (hard) rock. Arguably most drummers there tend to have the skins quite tight, which shifts up the resonance. Jazz would actually be lower.
But we are talking about real drums, not synthesized drums.
Actually, a stereo pair of speakers with music (which is usually mixed mono compatible, so much of the signal is correlated) will produce around 98dB with 1Watt RMS per speakers at 1m.
In an open field we find as we double our distance we loose 6dB SPL, unless we use highly directional (so called "long throw") systems. In a room it is not as easy. An easy rule of the thumb is to add an extra 2dB to the freefield.
So, with 4m listening distance (I'm more at 3m) we have around 10dB attenuation. So we get around 88dB SPL at the listening position for around 1 Watt per channel.
I have spend the occasional concert with a SPL Meter where I normally sit (sad, I know, but I wanted to know. In the 3rd to 5th row average SPL's for large orchestral works rarely exceeded these 88db. The crest factor was never more than 14dB. But I always design my tube amp's to tolerate 6dB
Oh, BTW, are you using your ears to listen? If you do, just be aware that the actual acoustic system in the ear produces around 30% THD at 92dB at the diaphragm. The few % from my speakers and tube Amp pales next to that. Which is probably why they remain inaudible.
30% Distortion - of course you have ears so you are okay with that.
Dear Doug - there are more things between heaven & earth than written about in harman technical papers.
Reality is a wee bit more complex than the two dimensional logic these and similar things employ.
In fact, having a fair bit of distortion of the right kind may be a "good thing" that you are missing 😛.
Ciao T
Ok, again please lets not start fighting. Doug thanks for being honest and not trying to sell something just to try to prove your point.
Like Thorsten says, if you want we can also talk about possible ways to improve the setup in the future with the least amount of money because I will mostly sure do it. ( I dont know when tough)
Talking aboout that, I was checking the speakers that I have right now that I bought at least 14 years ago from a guy I knew ( he made the boxes himself so go figure), and I see that the main woofers are actually subwoofers ( JBL GT102D ) so even though for what I see the response of those speakers doesnt go lower than 34 Hzor so in a vented enclosure as per JBL "recommended" in their literature, could they be used to make a better Subwoofer alternative than the Audiosource PSW-100 I have? I have 2 so maybe with the right amp I can make them work?
Of course that in the near future...
Leo
Like Thorsten says, if you want we can also talk about possible ways to improve the setup in the future with the least amount of money because I will mostly sure do it. ( I dont know when tough)
Talking aboout that, I was checking the speakers that I have right now that I bought at least 14 years ago from a guy I knew ( he made the boxes himself so go figure), and I see that the main woofers are actually subwoofers ( JBL GT102D ) so even though for what I see the response of those speakers doesnt go lower than 34 Hzor so in a vented enclosure as per JBL "recommended" in their literature, could they be used to make a better Subwoofer alternative than the Audiosource PSW-100 I have? I have 2 so maybe with the right amp I can make them work?
Of course that in the near future...
Leo
Hi,
You keep telling everyone they are doing it wrong. Now the OP asks YOU to tell him how to do it right and what the difference will be. He seems prepared to save up some if you convince him that it is worth the extra outlay.
And you say "I guess what the others tell you is okay enough, but be aware there are compromises involved" (BTW, I think i stated clearly what the tradeoffs are, in each of my suggestions).
So, please tell the OP how to achieve a system that attains your approval on a tight budget. Or do I need to do that for you?
He posted:
That was Leo's question to YOU. Do I need to answer it because you cannot?
Ciao T
You keep telling everyone they are doing it wrong. Now the OP asks YOU to tell him how to do it right and what the difference will be. He seems prepared to save up some if you convince him that it is worth the extra outlay.
And you say "I guess what the others tell you is okay enough, but be aware there are compromises involved" (BTW, I think i stated clearly what the tradeoffs are, in each of my suggestions).
So, please tell the OP how to achieve a system that attains your approval on a tight budget. Or do I need to do that for you?
He posted:
Lambo240z said:
That was Leo's question to YOU. Do I need to answer it because you cannot?
Ciao T
I never posted you are doing it main speaker build wrong.....the only discussion we have a different opinion on is the bass discussions. I have no opinion on the main XOs Im pretty sure they are going to be great.
btw, if you want to answer his questions then do it, why does it matter who answer....the goal is to help him not stroke any ego.
There is a lot of meat in the build already and I have not followed everything so its kind of foolish to give any direction to the actual build.
My only point all along is to have LFE and a proper subwoofer, bass management setup. Other then that, He should try to go as low as possible.
If he now is considering LFE then a lot more details are needed.
btw, if you want to answer his questions then do it, why does it matter who answer....the goal is to help him not stroke any ego.
There is a lot of meat in the build already and I have not followed everything so its kind of foolish to give any direction to the actual build.
My only point all along is to have LFE and a proper subwoofer, bass management setup. Other then that, He should try to go as low as possible.
If he now is considering LFE then a lot more details are needed.
Hi,
I think there may be some more mileage in them. But I always believe the Subwoofer should be a number or two bigger than a Woofer.
So for your 15" Woofers, have a look at 21" and 24" Subs. See if you can find a nice working single unit from someone who has blown the second one up. I used to frequent 2nd pro-audio shops looking for such to make subwoofers for friends (I mean serious subs, with a long throw 18" or larger driver), there are often surprising bargains to be had.
You could build a marble topped Sofa Table with the woofer in the bottom, or a Sonotube "column" to stand in a corner. There are quite a few interesting "hiding" options.
You can also look if your existing receiver has a tape loop or pre-out / power-in option. If so, you may be able to apply a simple DIY option (even passive line level) to offer some analogue bass management and even a summing system to redirect all low bass to the Sub.
All that can be done at fairly low cost, however, lets finish you two main speakers first. And make sure they can play for themselves for now. Then we can push the envelope.
I just finished putting together the speakers for a new Kit I'm developing.
These use the same 10" Woofers I use at home with 35 Tube Watts. For that kit they are driven with a lot more power (~ 400W) from a fairly budget Subwoofer Class D Amplifier. I tried them in our 1700ft^2 warehouse. Nice.
I still think your Peaveys plus the rest will do more than okay in your current situation, unless you want Insanely LOW and Insanely LOUD. Adding a serious sub can help getting closer, but may not be essential (unless your Doug).
Ciao T
I think there may be some more mileage in them. But I always believe the Subwoofer should be a number or two bigger than a Woofer.
So for your 15" Woofers, have a look at 21" and 24" Subs. See if you can find a nice working single unit from someone who has blown the second one up. I used to frequent 2nd pro-audio shops looking for such to make subwoofers for friends (I mean serious subs, with a long throw 18" or larger driver), there are often surprising bargains to be had.
You could build a marble topped Sofa Table with the woofer in the bottom, or a Sonotube "column" to stand in a corner. There are quite a few interesting "hiding" options.
You can also look if your existing receiver has a tape loop or pre-out / power-in option. If so, you may be able to apply a simple DIY option (even passive line level) to offer some analogue bass management and even a summing system to redirect all low bass to the Sub.
All that can be done at fairly low cost, however, lets finish you two main speakers first. And make sure they can play for themselves for now. Then we can push the envelope.
I just finished putting together the speakers for a new Kit I'm developing.
These use the same 10" Woofers I use at home with 35 Tube Watts. For that kit they are driven with a lot more power (~ 400W) from a fairly budget Subwoofer Class D Amplifier. I tried them in our 1700ft^2 warehouse. Nice.
I still think your Peaveys plus the rest will do more than okay in your current situation, unless you want Insanely LOW and Insanely LOUD. Adding a serious sub can help getting closer, but may not be essential (unless your Doug).
Ciao T
Yes, I will make these speakers and see if they seem to need a better sub that the one I have, if thats the case I will cross that bridge when needed.
I think Loren was doing some measurements of the Audax you needed right?
Also, I know you guys said that it is a little better to be sure and do the cabinets with the golden ratio, but I was looking around the size and didnt like it too much 🙁
What I mean is, I have been thinking about designing a really cool cabinet that could not be seen as huge boxes.
So I know that as far as I keep the internal volume, the golden ratio can be broken with not many audible differences ( as I understood ) but here go some other questions:
I know that I should keep the other drivers at the same distance to the listener ( horizontal) but is there a requirement to the vertical distance between them? ( I dont mean huge distance)
Also I understand that the size of the cabinet for the woofer combined with the size of the vent or vents determines the lower frequency that driver will be able to achieve.
So if I make the cabinet smaller, the lower frequency will be raised right? If the size gets smaller but not too much, can it be compensated by more vents or bigger ones for example?
Thanks.
Leo
I think Loren was doing some measurements of the Audax you needed right?
Also, I know you guys said that it is a little better to be sure and do the cabinets with the golden ratio, but I was looking around the size and didnt like it too much 🙁
What I mean is, I have been thinking about designing a really cool cabinet that could not be seen as huge boxes.
So I know that as far as I keep the internal volume, the golden ratio can be broken with not many audible differences ( as I understood ) but here go some other questions:
I know that I should keep the other drivers at the same distance to the listener ( horizontal) but is there a requirement to the vertical distance between them? ( I dont mean huge distance)
Also I understand that the size of the cabinet for the woofer combined with the size of the vent or vents determines the lower frequency that driver will be able to achieve.
So if I make the cabinet smaller, the lower frequency will be raised right? If the size gets smaller but not too much, can it be compensated by more vents or bigger ones for example?
Thanks.
Leo
There are rules for ideal distances between drivers, as you probably have guessed.
The general rule is that the spacing between drivers should be no greater than one wavelength at the crossover frequency.
For a crossover at 2,500 Hz you should have a center to center distance no greater than 5.4".
With the Audax mid this is almost impossible. Indeed, I had to cut a curved section out of my tweeter's mounting flange to meet that requirement. See HERE:
For the woofer and mid it is not so bad. One wavelength at 500 Hz is just a bit over 27". That is easy to do.
Why do you want the tight spacing?
When multiple sources are used to produce sound, the two sources can interfere with each other at the overlap frequencies. You can illustrate this if you drop two pebbles into a still water and watch the waves combine.
For audio, the combination can produce comb filtering effects where some frequencies are reinforced and others create a null. Move your listening position and the effect changes to different frequencies.
The best solution is to have all three speakers at the same point. Obviously, three drivers can not occupy the same time-space coordinates, so the next best thing is a tight vertical alignment with the woofer at the bottom and the tweeter at the top, and that is exactly the way I designed my cabinet.
Now, there are other things that you might want to consider when doing your layout of the baffle. It is good practice to place your drivers off center of the baffle to reduce diffraction.
Perhaps a better solution is to round over the front edges of the cabinet with a radius of 2" or more. It would be good practice to round over the back edges of the cabinet, too, but less important than the front edges.
All drivers should be flush mounted to the baffle so that the driver flange and baffle are flush to each other.
Ports can be on any surface. Front mounting the ports is marginally better than the rear, but the acoustic distance between the woofer cone and the ports on the back of the cabinet is small compared to the wavelengths that they operate at.
Ideally, I prefer the ports being forward firing to avoid firing into corners and walls, which is where the back of cabinets are usually facing. The draw back is that it is a little harder to measure near-field frequency response of the drivers and ports due to cross contamination. That hangup is really not something you should really worry about.
The front face of my cabinet has the sides adjacent to the mid and tweeter folded back at about 30°. This was done to ease refraction. Measurements to date seem to support that tactic. The drawback is that the construction of the cabinet is complex and requires complex angles cut into each panel with precision.
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Yes, there are mathematical relationships between the tuned point (Vb) of a vented cabinet and the volume of the cabinet and the port size.
Changing any one variable will impact the the Vb of the system. For instance, enlarging the port size will actually require the length to be increased substantially to keep Vb constant.
The best solution for you would be to design the cabinet shell as big as you can (closest to ideal internal volume), then rerun the box simulation and tune the ports for the new shell.
You must also compensate that internal volume for the volume taken up by the port tubes, driver, cross braces, and crossover. This is the net internal volume.
Hi Leo,
Something like this. I hope I can spend some time this WE to run the sims for your speaker.
I have been kinda busy, among other things I assembled (including documenting the build for the Kit manual) this:
600Hz first order crossover for the tops, appx. 60hz for the Sub to the tops.
I'm thinking of making a "grown up" version of this for my own use, with full cardiode radiation down to sub levels, so I can play 1812 without upsetting neighbours (living in a semi-detached).
That is okay. You can turn it to the side (though wide baffles sound/image better if done right), as I did in the above.
The golden ratio was good enough for Archimedis, Frank LLoyd Wright and Buckminster Fuller. But you do not HAVE TO use it. It just confers some advantages. Whatever you do, try avoiding dimensions that are integer multiples of each other.
We all try. With limited success. A 150 Liter box is a 150 liter box. 150 liters are not small....
As it happens, the design I propose uses the Audax to cover most of the audible range, with the rest handed off. Within reason (say 50cm) you can separate the Peavey Woofer and Audax. The Audax and Fostex should be mounted as close as possible, but the crossover is so high, the distance problem is defused by the fact that hearing acuity goes to hell in a handbasket above 4...5KHz for most people.
To a degree. Just find and download either winisd Alpha or if this is too difficult my own "Xlbox" spreadsheet, which has the advantage of including some (not all) of the room effects. I designed it primarily for quick "feasibility study" of drivers and boxes. It gets you into the ballpark.
No, it does not work like that.
Think of vented boxes as weight/spring system. They need to combine in the right way.
Ciao T
Something like this. I hope I can spend some time this WE to run the sims for your speaker.
I have been kinda busy, among other things I assembled (including documenting the build for the Kit manual) this:
An externally hosted image should be here but it was not working when we last tested it.
600Hz first order crossover for the tops, appx. 60hz for the Sub to the tops.
I'm thinking of making a "grown up" version of this for my own use, with full cardiode radiation down to sub levels, so I can play 1812 without upsetting neighbours (living in a semi-detached).
That is okay. You can turn it to the side (though wide baffles sound/image better if done right), as I did in the above.
The golden ratio was good enough for Archimedis, Frank LLoyd Wright and Buckminster Fuller. But you do not HAVE TO use it. It just confers some advantages. Whatever you do, try avoiding dimensions that are integer multiples of each other.
We all try. With limited success. A 150 Liter box is a 150 liter box. 150 liters are not small....
As it happens, the design I propose uses the Audax to cover most of the audible range, with the rest handed off. Within reason (say 50cm) you can separate the Peavey Woofer and Audax. The Audax and Fostex should be mounted as close as possible, but the crossover is so high, the distance problem is defused by the fact that hearing acuity goes to hell in a handbasket above 4...5KHz for most people.
To a degree. Just find and download either winisd Alpha or if this is too difficult my own "Xlbox" spreadsheet, which has the advantage of including some (not all) of the room effects. I designed it primarily for quick "feasibility study" of drivers and boxes. It gets you into the ballpark.
No, it does not work like that.
Think of vented boxes as weight/spring system. They need to combine in the right way.
Ciao T
Thanks a lot Loren! That has been highly informative 🙂
Now I can start designing the cabinet with that in mind and see where I can get.
The distance of the Mid to Tweeter in my case will be more troublesome or smaller since I think Thorsten said the crossover will be at 8KHz. That means the distance shoud be 1.8" only!
Well I guess that means I have to put it as close as possible 🙂
Another thing, you said the distance has to be NO MORE THAN... if it is shorter than that, it doesnt make any problems right? Is there a distance that is Golden also?
Leo
Now I can start designing the cabinet with that in mind and see where I can get.
The distance of the Mid to Tweeter in my case will be more troublesome or smaller since I think Thorsten said the crossover will be at 8KHz. That means the distance shoud be 1.8" only!
Well I guess that means I have to put it as close as possible 🙂
Another thing, you said the distance has to be NO MORE THAN... if it is shorter than that, it doesnt make any problems right? Is there a distance that is Golden also?
Leo
Thanks Thorsten, now I have some more information to design the cabinets. Hopefully I can come up with something that will meet the requirements and still look cool.
Leo
Leo
Just make the mid and tweeter as close as you can. The woofer has a little more latitude, so you don't need to jam them together.
The optimum distance for all drivers is a single point in space. After that, the closer is generally better.
As ThorstenL pointed out, the tweeter crossover point is way beyond the point of possibility, so just butt them up together.
ThorstenL, I should have that data for you tomorrow. I have to make a jig to hold the drivers to get the Audax impedance and T/S data for you. I am installing Woofer Tester 2 on my laptop right now.
Shame I don't have that Peavey laying around, too. I have a Peavey BW Low Rider in the attic, but that is a much different animal than the 1502-8.
Ok, I have been using WinISD and finally was able to add the Peavey Black Widow with the parameters. It seems that you can only add so few parameters and not everything or it will give you an error. Also on Windows 7 the Help doesnt work 🙁
Anyway, if I input a 100 liter box with the vent of 16 cms by 10 cms by 17 cms deep, the tuning frequency goes form the original 40 Hz ( with the original setup suggested here )to 41.7 Hz.
Can you guys run this on Bassbox to make sure the difference is actually that small and if the F3 doesnt shift too much (or any other important parameter for that matter) and see if it is feasable?
Because that size cabinet would be much nicer than the 150 liter one 🙂
Thanks.
Leo
Anyway, if I input a 100 liter box with the vent of 16 cms by 10 cms by 17 cms deep, the tuning frequency goes form the original 40 Hz ( with the original setup suggested here )to 41.7 Hz.
Can you guys run this on Bassbox to make sure the difference is actually that small and if the F3 doesnt shift too much (or any other important parameter for that matter) and see if it is feasable?
Because that size cabinet would be much nicer than the 150 liter one 🙂
Thanks.
Leo
Your calculations are pretty close to what I got in LEAP. The exact tuning length seems to depend on the amount of fill used inside the cabinet. I ended up with 50% fill because there is a nasty resonance at about 550 Hz that causes a sharp dip followed by a spike.
The other drawback is the lower end suffers when you go with a smaller box. You should be able to model this yourself to see the effect. Given you are bass starved with the Peavey already I would tend to live with the larger box to try to recapture as much bass as possible.
Here is the 100 liter box tuned to 41.7 Hz:
An externally hosted image should be here but it was not working when we last tested it.
Compare that with a 150 liter box tuned to 40 Hz:
An externally hosted image should be here but it was not working when we last tested it.
That is a pretty huge difference and I would seriously consider your poison. 😀
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Loren42, let me ask, if you know, (for when modeling/sim) what kind of measurement was done on the Peavey (open baffle, closed box, size) for the FRD's (and in the case if you make new one/s)?😱
All I have is the model that is in the LEAP5 library. I can't be sure how good it really models the real thing, but everything I have been able to read about the models tells me that it should be pretty damn close to the real deal. At least close enough to get a very good idea of what to expect.
There are a series of plots that LinearX did to demonstrate the fit between the model and the real driver in the modeled cabinet. They do a very good job of getting it right. At least that is the marketing hype.
The modeling technique LEAP uses is unique (proprietary) and depends on the impedance curve of the drive, the mechanical/physical properties of the magnet pole, it's gap, and the voice coil. Given those parameters LEAP5 generates the driver model, which should closely match the actual driver's performance.
If someone would care to donate a Peavey 1502-8 and some petty cash I would be happy to an actual comparison. 😀
I just checked the library for this driver and it is the TSL model. The TSL model is supposed to be the most accurate model they have. My understanding is the library set they have was predominantly measured by Vance Dickason. If you have read his books you just may notice that he mentions LEAP maybe one or twice in the course of the book. 🙂
Lastly, I am new to this software and I believe that I am doing things correctly, but I can't proclaim I am an expert.
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Too bad I am not in Miami anymore, I could have given you the Speaker 🙁
Anyway here is a comparison of both in 1 drawing.
So the area between 30 and 60 Hz is the big deal, I see, it gets to be up to 4 dB higher and that is pretty noticeable right?
Ok I will try to see another possibility, and bug you 1 more time to model it. If it doesn't show that I can go smaller without compromising the quality at low frequencies, then I will have to start designing something with the 150 Liter one.
Thanks Loren.
Leo
Anyway here is a comparison of both in 1 drawing.
So the area between 30 and 60 Hz is the big deal, I see, it gets to be up to 4 dB higher and that is pretty noticeable right?
Ok I will try to see another possibility, and bug you 1 more time to model it. If it doesn't show that I can go smaller without compromising the quality at low frequencies, then I will have to start designing something with the 150 Liter one.
Thanks Loren.
Leo
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