New BassChat 8"Cab design

[Phil Starr]

I'm not familiar with this cab and frankly I don't believe some of the advertising nonsense about the resonator technology so I've kept away from offering too much advice. There is also good reason why most people don't use thin ply for cabs that live on the road and feet pulling out is something that really should not happen. I hope this was addressed in later versions.

 

Anyway you don't need to worry about covering the holes in an internal partition, the white damping material is more or less transparent to sound, some hifi cabs are completely filled with polyester wadding and even have it compressed they even use wool, mineral fibre or glass wool in cabs. 

 

Anyway from basic principles the wadding in the cab should either be fixed to panels or the cab should be stuffed in such a way that it stays in place. Loose wadding needs to be kept away from the ends of any ports where the hopefully trouser flapping volume will also flap loose wadding  If the wadding is meant to be fixed staples alon aren't really enough and I'd use some spray adhesive as well. Vent the cab after using the spray adhesive as the solvents might affect the speakers.

 

The pressure changes at the resonance of the cab can be quite high and it will find any weak spots and create a rattle or buzz. Buzzing is higher frequency than the fundamental of course. Buzzing could be any mating surfaces in the cab including the speaker drivers and the glue joints between panels. You can exagerate them with a 50hz signal (there are plenty of online signal generators) amplified to high volumes but they are hard to find because of course they have loud sound from the 50hz sinal to hide behind. Just because you have found one buzz it doesn't mean there aren't others.

 

That looks like a very standard switch on the back of the cab, you should be able to de-solder it and put in a new one or find a competent repair tech who can do it for you cheaper than a new panel.

 

Good luck

[rwillett]

On 13/10/2025 at 19:15, tauzero said:

After using the shitty house Orange 50W bass combo a couple of times at a local open mic (absolutely dreadful, the front end goes into clipping almost instantly even with the pad on), I thought I'd build one of these to pair either with a TC BAM200 or Tecamp Puma 900 to use there. Interestingly, a search on Ebay for the Fane Sovereign 225-8 gave various results with shipping costs being displayed but when I clicked on https://www.ebay.co.uk/itm/125957204831 it showed shipping as zero instead of a few quid, so that's the one. A trip to B&Q beckons - I think I'll eschew their free cutting service, the last time I took advantage of it didn't fill me with confidence. Looks like materials cost should come in at around £90 given that I have several speakers worth of drainpipe in the shed.

 

Just in case it helps, I'd be happy to print a port up for you to play with. This is a cross section of a 125mm port. The purple is the drain pipe (or whatever, it's simply there to show where it fits), the red is the flange that the pipe connects to.

 

It's all parameterised so I just made it 50mm as opposed to 125mm. It even has your name on it

 

I've added chamfers in but no idea if they help or not.

Rob

 

 

[Obrienp]

Thank you @Phil Starr for the advice.
 

Unfortunately, it looks like that DPDT switch (which, as you say is very standard) is attached to the PCB stuck on the back of the unit. I am not sure whether it will be within my capabilities to replace it. That PCB is mounted on a 50mm chunk of ply attached to the metal plate. Not sure why they did that. I assume it was to give it sufficient mass to resist vibration but it also protrudes a long way into the cabinet. I would have thought creating a long lever would make it amplify any movement in the plate.

 

One supplementary question: should there be any wadding in the back compartment of the cabinet; ie the space behind the internal baffle? Would it help reduce the resonance if I put some in? I would be careful not to block the port that is at the bottom of that compartment. At the moment the cabinet vibrates so much (when I hit Eb, E, F) that the amp starts to dance about on top.

 

Thank you for your forbearance. As must be obvious, this is far from my area of expertise.
 

 

[Pea Turgh]

Maybe some of the internal bracing was damaged when the foot incident occurred?  Sounds like more than a damping issue to me. Could send it to Alex for an assessment then claim on insurance?

[Obrienp]

9 minutes ago, Pea Turgh said:

Maybe some of the internal bracing was damaged when the foot incident occurred?  Sounds like more than a damping issue to me. Could send it to Alex for an assessment then claim on insurance?

Thank you for the suggestion. Fortunately, it was just a little damage to the ply where the feet were located: the two on the front side of the cab, so I was able to inspect it thoroughly when I removed the drivers. The only internal bracing is the internal baffle board assembly, as far as I could see. There is certainly nothing loose inside. I reinforced the area where the ply was damaged with some rectangles of 8mm ply, glued and stapled. I am pretty sure that is not moving and the buzzing is not coming from that area.
 

TBH this cab always vibrated a lot at volume. I guess that is what comes from the lightweight construction: 10mm ply throughout. I always put a non-slip mat on top when gigging it. The buzz is something I hadn’t noticed before but I haven’t used it for a while. I have been using my LFSys Monzas, which are made of thicker ply and don’t vibrate as much. Now I have heard the buzz, I can’t un-hear it. 
 

I probably do need to consult Alex but I wanted to get an impartial view first. Unfortunately, the cab isn’t insured and the incident with the feet happened a couple of years ago.

[tauzero]

2 hours ago, rwillett said:

 

Just in case it helps, I'd be happy to print a port up for you to play with. This is a cross section of a 125mm port. The purple is the drain pipe (or whatever, it's simply there to show where it fits), the red is the flange that the pipe connects to.

 

It's all parameterised so I just made it 50mm as opposed to 125mm. It even has your name on it

 

I've added chamfers in but no idea if they help or not.

Rob

 

 

 

Thanks, but I've used the drainpipe successfully in three speakers so far and I know my hole saw does the job for it. Oh, and it's Tau not Tao!

[Phil Starr]

4 hours ago, rwillett said:

 

Just in case it helps, I'd be happy to print a port up for you to play with. This is a cross section of a 125mm port. The purple is the drain pipe (or whatever, it's simply there to show where it fits), the red is the flange that the pipe connects to.

 

It's all parameterised so I just made it 50mm as opposed to 125mm. It even has your name on it

 

I've added chamfers in but no idea if they help or not.

Rob

 

 

That looks like something a lot of home builders would want, probably not something you would want to print in huge numbers though. I've often wondered what it would cost to produce a batch of these to fit drainpipe and soil pipe, the most common material used for making ports. They would certainly tidy up a lot of wonky hole cutting

[rwillett]

3 minutes ago, Phil Starr said:

That looks like something a lot of home builders would want, probably not something you would want to print in huge numbers though. I've often wondered what it would cost to produce a batch of these to fit drainpipe and soil pipe, the most common material used for making ports. They would certainly tidy up a lot of wonky hole cutting

Phil

 

It's relatively easy now as I parameterised everything, so it's a case of plugging the right numbers into it and its automatically updated. So if the wall thickness of the pipe goes from 2.5mm to 3mm, I change a singe parameter and thats it.

 

In some respects every print I ever do is bespoke. Printing 5,000 of these on a 3d printer would not be cost effective as you could tool up to do this using better methods. Printing a few dozen identical ones probably would be cost effective as there are no tooling setup costs. Printing individual ones would certainly be cost effective as the design is done and it's just plugging numbers in and then sending them to print. No need to tool up.

 

I wouldn't print all of the port, just the flange as it's cheaper to buy piping. However if you wanted a hex port or an elliptical one or a triangular one, that's very simple to do as the methodology is the same.

 

If you want a one off, let me know. I'll do it for nothing, your speaker shoot out was great and this is one way to pay for that  

Rob

[Phil Starr]

3 hours ago, Obrienp said:

Thank you for the suggestion. Fortunately, it was just a little damage to the ply where the feet were located: the two on the front side of the cab, so I was able to inspect it thoroughly when I removed the drivers. The only internal bracing is the internal baffle board assembly, as far as I could see. There is certainly nothing loose inside. I reinforced the area where the ply was damaged with some rectangles of 8mm ply, glued and stapled. I am pretty sure that is not moving and the buzzing is not coming from that area.
 

TBH this cab always vibrated a lot at volume. I guess that is what comes from the lightweight construction: 10mm ply throughout. I always put a non-slip mat on top when gigging it. The buzz is something I hadn’t noticed before but I haven’t used it for a while. I have been using my LFSys Monzas, which are made of thicker ply and don’t vibrate as much. Now I have heard the buzz, I can’t un-hear it. 
 

I probably do need to consult Alex but I wanted to get an impartial view first. Unfortunately, the cab isn’t insured and the incident with the feet happened a couple of years ago.

I wouldn't add wadding to someone else's design other than to try it out. It's ok to try something and listen for a difference and decide which you prefer if it's easy to return to it's original form, but without a good reason to think it was 'wrong' in the first place I'm not sure I'd expect to get an improvement. 

 

I dont think wadding of any sort is going to fix buzzing which is caused by one thing vibrating against another. Something is loose that shouldn't be. The '50mm chunk of ply sounds like a bodge and could be the source of your problem. I'm picturing the PCB as a ruler being twanged against the ply. I'd want the PCB mounted properly, bolted to the plate with insulated stand offs https://uk.farnell.com/c/fasteners-mechanical/fasteners-fixings/spacers-feet/standoffs

 

[Phil Starr]

1 minute ago, rwillett said:

Phil

 

It's relatively easy now as I parameterised everything, so it's a case of plugging the right numbers into it and its automatically updated. So if the wall thickness of the pipe goes from 2.5mm to 3mm, I change a singe parameter and thats it.

 

In some respects every print I ever do is bespoke. Printing 5,000 of these on a 3d printer would not be cost effective as you could tool up to do this using better methods. Printing a few dozen identical ones probably would be cost effective as there are no tooling setup costs. Printing individual ones would certainly be cost effective as the design is done and it's just plugging numbers in and then sending them to print. No need to tool up.

 

I wouldn't print all of the port, just the flange as it's cheaper to buy piping. However if you wanted a hex port or an elliptical one or a triangular one, that's very simple to do as the methodology is the same.

 

If you want a one off, let me know. I'll do it for nothing, your speaker shoot out was great and this is one way to pay for that  

Rob

Thanks Rob, it was good to meet you. I've been following your printed bass builds for years and the biggest regret at the bash was not taking time to see one in the flesh. I've had a lot of pleasure from quietly watching your exploits and I'd love to have a go at 3d printing, but I don't need another hobby yet  Your thread has already paid back anything I was able to offer you in return.

 

Thanks for the offer but somone has printed me off a similar flange already. The plan was to take it across to @stevie to see if it made a reduction in port noise possible. I haven't got around to using that one yet so it would probbly be wasted on me to print a new one. 

[Obrienp]

9 minutes ago, Phil Starr said:

I wouldn't add wadding to someone else's design other than to try it out. It's ok to try something and listen for a difference and decide which you prefer if it's easy to return to it's original form, but without a good reason to think it was 'wrong' in the first place I'm not sure I'd expect to get an improvement. 

 

I dont think wadding of any sort is going to fix buzzing which is caused by one thing vibrating against another. Something is loose that shouldn't be. The '50mm chunk of ply sounds like a bodge and could be the source of your problem. I'm picturing the PCB as a ruler being twanged against the ply. I'd want the PCB mounted properly, bolted to the plate with insulated stand offs https://uk.farnell.com/c/fasteners-mechanical/fasteners-fixings/spacers-feet/standoffs

 

Thank you again for the advice. 
 

I’m pretty sure the switch is Barefaced OEM. I found a video of Alex demonstrating the procedure for opening up a Two10S and the switch assembly looked the same. It was meant to be a demo of installing a switch kit but he used a Two10S and just discussed how to install the kit, rather than actually doing it. I don’t think I would have found that too helpful, if I was about to try to do it. However, he did mention that the coil and magnet assembly tie-wrapped to one of the speaker frames should be removed. It’s still there in my cab, so it’s obviously a conversion that wasn’t executed perfectly. I’ve been searching for written instructions on their website but very few of the technical links seem to work anymore. An email to Alex is in order.

[Chienmortbb]

5 hours ago, rwillett said:

I've added chamfers in but no idea if they help or not.

I think they will help, especially the inner chamfer. However of all the black arts in cabinet design, flared ports is the darkest. Whether there would be much improvement in copying say a precision ports design I don’t know. While flare reduce port noise, this really masks the port’s limitations caused by its small diameter. Of course I could be talking complete tosh. 
 

[rwillett]

12 minutes ago, Phil Starr said:

I've been following your printed bass builds for years and the biggest regret at the bash was not taking time to see one in the flesh. I've had a lot of pleasure from quietly watching your exploits and I'd love to have a go at 3d printing, but I don't need another hobby yet  Your thread has already paid back anything I was able to offer you in return.

 

Thanks for the offer but somone has printed me off a similar flange already. The plan was to take it across to @stevie to see if it made a reduction in port noise possible. I haven't got around to using that one yet so it would probbly be wasted on me to print a new one. 

Phil,

 

Get another hobby, what can possibly go wrong  

 

The offer is there if you wish to take it up. The design is done, so its easy to change as needed. The printing time is dependent on the size but it's not excessive TBH. I tend to print in terms of 8-14 hours, so a few hours here or there is nothing, so if you want to test out different configurations, very happy to help. e,g, Put a straight chamfer on the inside of the pipe vs a rounded edge (bull nose) or having the output bigger than the pipe (no idea why you'd do that but it can be done).

 

Very happy to help as one day I may manage to find the time to build a speaker 

 

Rob

[rwillett]

6 minutes ago, Chienmortbb said:

I think they will help, especially the inner chamfer. However of all the black arts in cabinet design, flared ports is the darkest. Whether there would be much improvement in copying say a precision ports design I don’t know. While flare reduce port noise, this really masks the port’s limitations caused by its small diameter. Of course I could be talking complete tosh. 
 

This is when 3d printing can help. My knowledge of flared ports is even less than my knowledge of unflared ports. However it costs very little to print different versions out and try them and see. I've been playing with different ways to construct guitars and testing out options. TBH, they didn't work, but I now know they don't work. 

 

I can print up to 220mm in external diameter, the actual port would be somewhat less (190mm+), but I suspect that's a massive port.

 

Thanks

Rob