New BassChat 8"Cab design

[Phil Starr]

You'd need to find the centre of gravity, I haven't got the cab here but I suspect it would be forward of the mid line. Then depending upon the tilt wanted you might need the support at the front. Guitar combos tend to be top heavy.

[Matt P]

13 minutes ago, Phil Starr said:

You'd need to find the centre of gravity, I haven't got the cab here but I suspect it would be forward of the mid line. Then depending upon the tilt wanted you might need the support at the front. Guitar combos tend to be top heavy.

 

very true! I'd forgotten that the 8" cab will be quite front heavy, my other thought was to make a simple folding stand with a v-shaped cutout to hold the amp, 3 bits of wood and a couple of hinges would probably do it, I might just have to experiment when the box is built.

 

Matt

[SamIAm]

2 hours ago, Phil Starr said:

You'd need to find the centre of gravity, I haven't got the cab here but I suspect it would be forward of the mid line. Then depending upon the tilt wanted you might need the support at the front. Guitar combos tend to be top heavy.

So a "bracket" on the bottom panel at the centre of the front edge.

If this is recessed into the cab, might it adversely affect the acoustics?

If it is a surface mount, it would protude ... but if one were to mount 4 rubber feet on the bottom this should give enough clearence for a mount; then a short length of doweling (with a rubber cap at the ground end) which push fits into the "bracket"?  One could have a coupld of slightly different lengths to allow for different angles.  If the cab is front heavy then gravity should hold the dowling in the bracket and so long as it is not sloppy loose hopefully it will not vibrate?

 

S'manth x

 

[Downunderwonder]

Also stows in bass case or gig bag.

[FirstBass]

So....

 

Just finished tuning the cab to 60hz using a frequency generator app and some rice....

 

With the 75mm blue aran port at "supplied" length we were tuned to about 57hz.

 

A quick snippy snip with the tin snips (superb for trimming plastic ports) and the rice stopped dancing on the cone at 60hz.

 

How does it sound? Sweet! Let's be realistic here. You're not going to tear faces off at the dog & duck with a single 8" cab, but for it's teeny tiny size it puts out a good chunk of thunk. I could definitely see two of these doing a pub gig with a tame drummer. 

 

Surprising amount of top end given there isn't a tweeter in sight. My old bass is well overdue a string change and it still chimed quite pleasantly.

 

I will just repeat THIS IS NOT PHILS DESIGN! 

 

I was an impatient s*d and wanted to crack on. 

 

Am I pleased? Yep. I will definitely carry on and finish this little beast off cosmetically.

 

There's some 9mm ply in the garage too 😉

 

Radio silence from me for a little while now as I don't want to tread on Phil's toes when his design gets uploaded. I feel as though I've posted too much already, but I had his blessing and wanted to get the old juices going out there in bass chat land...

 

If you're contemplating building one then go for it! It's good fun, pretty cheap and very rewarding 👍

 

 

[Phil Starr]

46 minutes ago, GlamBass74 said:

Just finished tuning the cab to 60hz using a frequency generator app and some rice....

 

With the 75mm blue aran port at "supplied" length we were tuned to about 57hz.

 

A quick snippy snip with the tin snips (superb for trimming plastic ports) and the rice stopped dancing on the cone at 60hz.

 

How does it sound? Sweet! Let's be realistic here. You're not going to tear faces off at the dog & duck with a single 8" cab, but for it's teeny tiny size it puts out a good chunk of thunk. I could definitely see two of these doing a pub gig with a tame drummer. 

 

Surprising amount of top end given there isn't a tweeter in sight. My old bass is well overdue a string change and it still chimed quite pleasantly.

Get some decent strings on that bass and give us a proper review

 

Seriously this is going to sound just about identical with our cab so anything you say about the sound is pretty much going to apply for anyone who builds my design, only the aesthetics will differ. The advantage of small speakers is that with lighter cones you tend to get an extended frequency range especially if the cone is designed to flex in a controlled way. If you look at the graph on p1 of this thread you'll see the Fane has a significant output up to 10kHz. It's not flat but the peak at 4kHz adds a bit of top end sparkle. As you'd expect from an 8" speaker the off axis response starts to drop at 500Hz but it holds it together up to 2kHz. It pretty much covers all the higher frequencies you'll get out of an electric bass. The top end was about as good as I could find out of an 8" speaker so I'm pleased you've commented on it. How do you like the bottom end? I was quite proud of how full that sounds if you don't expect to drown out Phil Collins' Gorilla on the drums. for our younger viewers

 

Go on I dare you to take it to rehearsal, back off the bass a little and shove the little fella into a corner turn the amp up and watch your bands faces

 

Seriously though well done and I'd love a longer review once you've got used to it.

Edited July 17, 2023 by Phil Starr

[FirstBass]

One more pic.... I has finished it.

 

Came out well... Apart from a router incident but I somehow managed to salvage it. 

 

7.2kg. 

 

Now off to give it a spanking 😁

 

 

Edited July 20, 2023 by GlamBass74

[Phil Starr]

That's a lovely job, really love the grille

[FirstBass]

its a really thin aluminium sheet I got from EBay for another cab I was building (that failed dismally - basslite 10 with corner ports - sounded awful)

 

Light as a feather, but man enough to protect the little fane.

 

Makes me laugh how the strap handle is almost as wide as the cab! 

 

Spend a good hour or two having a noodle through it yesterday. It's a little gem. 

 

[chyc]

I love it! At that price it's a very tempting proposition for a fool with his tools such as myself.

 

I'm looking forward to seeing the final design. If I have enough scrap wood to make it, I probably will. Failing that, I see that BnQ do some "nice" (for BnQ's definition of nice) 9mm exterior plywood at a reasonable price. I presume there won't be a tweeter option of this cab? Been having some interesting discussion with @GlamBass74 about port placement. I'd personally like to have a downward port, because I think ports are best heard not seen. He has managed to convince me it would affect the tuning frequency  but I'm not sure if I'd notice it enough.

 

All exciting stuff. My BC112mk3 building has hit an impasse with the lack of available components, sadly.

[SamIAm]

It is a beauty!

Once I'm back in my flat (Mid Sep) I am going to try to build one too!

S'manth x

[Phil Starr]

4 hours ago, chyc said:

I love it! At that price it's a very tempting proposition for a fool with his tools such as myself.

 

I'm looking forward to seeing the final design. If I have enough scrap wood to make it, I probably will. Failing that, I see that BnQ do some "nice" (for BnQ's definition of nice) 9mm exterior plywood at a reasonable price. I presume there won't be a tweeter option of this cab? Been having some interesting discussion with @GlamBass74 about port placement. I'd personally like to have a downward port, because I think ports are best heard not seen. He has managed to convince me it would affect the tuning frequency  but I'm not sure if I'd notice it enough.

 

All exciting stuff. My BC112mk3 building has hit an impasse with the lack of available components, sadly.

If I were building this for myself I'd rear mount the port, I'm not keen on downwards because it could potentially introduce a resistive element at the end of the port. I don't think that would be very significant but it would depend upon the length of the feet and possibly the surface underneath. It's been done successfully though. Rear mounting is convenient and it helps make a stronger baffle if you cut less of it away.

 

What's the problem with you BC112 mk3? We might be able to help.

[chyc]

 

Thanks Phil.

 

5 minutes ago, Phil Starr said:

If I were building this for myself I'd rear mount the port, I'm not keen on downwards because it could potentially introduce a resistive element at the end of the port.

I want downward port as an armchair expert for the following reasons.

1. It's out of sight
2. Usual design of cabinets it to get 'em tall, so that the moving parts are as close to the ear as possible. Why not take advantage of that so that your port can be as long and wide as possible, which would help with efficiency and chuffing minimization?
3. Too much low end? Put the cabinet on its side!

[tauzero]

23 minutes ago, Phil Starr said:

If I were building this for myself I'd rear mount the port, I'm not keen on downwards because it could potentially introduce a resistive element at the end of the port. I don't think that would be very significant but it would depend upon the length of the feet and possibly the surface underneath. It's been done successfully though. Rear mounting is convenient and it helps make a stronger baffle if you cut less of it away.

 

Does that mean you've revised the 8" to have a rear port, or is it remaining with the front port?

[Bill Fitzmaurice]

Bottom porting is perfectly feasible. It doesn't lower the tuning all that much, maybe by 3Hz. It acts more like a flare than an extension of the port. You just have to use cabinet feet at least 2.5cm high.

[Phil Starr]

8 hours ago, tauzero said:

 

Does that mean you've revised the 8" to have a rear port, or is it remaining with the front port?

I've kept the front port in the design I've sent off. When I write this up properly I'll just mention it as an option.

 

I want this to be as widely built as possible, as in all our designs, and people are just more comfortable with front ports. 

 

Equally I want to demystify cab building, partly because it is fun and partly so they can understand what they are buying from commercial builders. If @chyc wants a bottom port he should try it. I suspect it will make very little difference in practice to the sound though if he is going to use a bigger port he probably needs to think about making the cab bigger by the same volume so the air in the cab stays the same 20l

[Chienmortbb]

On 21/07/2023 at 15:20, chyc said:

 

Thanks Phil.

 

I want downward port as an armchair expert for the following reasons.

1. It's out of sight
2. Usual design of cabinets it to get 'em tall, so that the moving parts are as close to the ear as possible. Why not take advantage of that so that your port can be as long and wide as possible, which would help with efficiency and chuffing minimization?
3. Too much low end? Put the cabinet on its side!

When I modified the Ashdown After Eight, there was no room to put the port on the baffle or the back. So it is side ported. Thinking outside the box there. In fact, the port could go outside the box, but it would look as fugly as a Bose "sub on a stick" (joke).

[Bill Fitzmaurice]

Ports can go anywhere, as their radiation pattern is omnidirectional. But most players, let alone people in general, aren't aware of that, so they tend to avoid cabs that don't look conventional. Being well aware of this commercial cab manufacturers tend to avoid breaking out of the cookie cutter mold. What's the first comment you see about a new product? It's almost always about how it looks. Too bad we don't hear with our eyes. 🫢

[tauzero]

Is there a finalised design yet? I'm sure I'll be able to find a reason that I need this.

[Chienmortbb]

39 minutes ago, tauzero said:

Is there a finalised design yet? I'm sure I'll be able to find a reason that I need this.

I think the wheels are in motion and a proper drawing will be available soon.

 

Incidently, I put my Ashdown retroglide 800 through the original the other night. The other half was out, and the Neighbours are away. It can shift some air. It cannot compete with my LFSys Monaco, but would certainly do for many pub gigs and rehearsals.

[SamIAm]

1 hour ago, Chienmortbb said:

I think the wheels are in motion and a proper drawing will be available soon.

 

Incidently, I put my Ashdown retroglide 800 through the original the other night. The other half was out, and the Neighbours are away. It can shift some air. It cannot compete with my LFSys Monaco, but would certainly do for many pub gigs and rehearsals.

Oooh!  With a new job feeding my bank account a bit more and moving back into my own flat in a month or so I see making one of these looming in my future!  Tho I do need to figure out how to drive it using a battery powered amp ...

S'manth x

[Chienmortbb]

3 hours ago, Smanth said:

Tho I do need to figure out how to drive it using a battery powered amp ...

S'manth x

Firstly you need to decide what battery you want to use then what power you need from the amp to achieve the required volume /SPL. Then you can decide whether, like @Mottlefeeder, you want to use a car amp that combines the amp and a voltage multiplier. Alternately you can use a class D amp plus a separate voltage multiplier. Be aware that car amp makers exaggerate  even more than MI makers.
 

Next, do you need a preamp? What is the output of the modeller that you have designed?

 

It might be worth starting a new build thread to explore this further.

[Mottlefeeder]

25 minutes ago, Chienmortbb said:

...you can decide whether, like @Mottlefeeder, you want to use a car amp that combines the amp and a voltage multiplier. Alternately you can use a class D amp plus a separate voltage multiplier. Be aware that car amp makers exaggerate  even more than MI makers...

Most reputable car amp manufacturers specify Watts RMS into 4 ohms @ 1% distortion with a 14.4v in accordance with the 'Amplifier power standard CTA 2006' (I've also seen it written as CEA 2006). If in doubt, check the paperwork, not the silkscreen printing.

David

[Chienmortbb]

11 hours ago, Mottlefeeder said:

Most reputable car amp manufacturers specify Watts RMS into 4 ohms @ 1% distortion with a 14.4v in accordance with the 'Amplifier power standard CTA 2006' (I've also seen it written as CEA 2006). If in doubt, check the paperwork, not the silkscreen printing.

David

It's good to have your knowledge on this. My last dealings with car amps was a few decades ago. I was going to put some info here about non car audio amps, but will make an effort to declutter this thread and will start a new thread.

 

[JPJ]

On 22/07/2023 at 17:55, Chienmortbb said:

When I modified the Ashdown After Eight, there was no room to put the port on the baffle or the back. So it is side ported. Thinking outside the box there. In fact, the port could go outside the box, but it would look as fugly as a Bose "sub on a stick" (joke).

I find myself strangely attracted to the idea of external ports, in a sort of bass cab “Lloyds of London” building type way - very steam punk but not very practical for life on the road.
serious thought though, would top exiting ports help with hearing your bass when you’re crammed into the back corner of the “stage” at your local Dog & Duck?