12" Cab Diary Continued

[Stub Mandrel]

11 hours ago, ezbass said:

 

 

 

AIEEE!!!

[GlamBass74]

Clamps! 

 

Batteries! 

 

Mess! 

 

PROGRESS! 😁

 

Omni 15 tallboy wood collected today.

 

I think I have an addiction

[GlamBass74]

Me again

 

Bit more done

 

Cut the pipe with my band saw. Lifted the blade guide up as high as it would go and then gently rolled the tube round making sure I was hitting my 150mm markings

 

Came out a treat. 

 

Roughed the plastic surface up with sandpaper and then used a cheap n nasty spray in very fine coats. Came out fine. 

 

Stapled wadding in place

 

Have also fitted base, but no picture. 

 

Next up is some routing of the edges

 

Crossover headache is looming. I'll crack it, but its my least fave part

 

So far so good

 

One point to make. The top panel brace has a notch out of it as per the plans. I glued this to the top panel before i'd built the cab up

 

The brace that goes inside the notch is not on the centre line of the baffle. So, my notch was not quite in the right place

 

I enlarged the notch so its fine now, but it might be worth leaving the brace off until you can see where it needs to be 

 

hope that makes some kind of sense

 

This post was brought to you in association with Varta Batteries.....

[RichardH]

17 hours ago, GlamBass74 said:

Me again

 

Bit more done

 

Cut the pipe with my band saw. Lifted the blade guide up as high as it would go and then gently rolled the tube round making sure I was hitting my 150mm markings

 

Came out a treat. 

 

Roughed the plastic surface up with sandpaper and then used a cheap n nasty spray in very fine coats. Came out fine. 

 

Stapled wadding in place

 

One point to make. The top panel brace has a notch out of it as per the plans. I glued this to the top panel before i'd built the cab up

 

The brace that goes inside the notch is not on the centre line of the baffle. So, my notch was not quite in the right place

 

I enlarged the notch so its fine now, but it might be worth leaving the brace off until you can see where it needs to be 

 

hope that makes some kind of sense

 

 

Hi, thanks for that - I have adjusted the drawings to take account of this - I'll pop Stevie a revised version he can upload to the thread - does this look better?

 

[GlamBass74]

Hi

 

I just got ahead of myself really and should've fitted this just before I fitted the top panel 😊

 

 

[BlueMoon]

Zombie thread alert!!

 

Having ready through this great thread and the similar ones related to cabinet building, I'm about ready (I know - late to the party again) to start sourcing materials to build two single 12" cabinets.

 

Ongoing stocks of some of the components is proving a bit of a challenge over here, as well as rampant inflation, but I am confident that I'll be able to make-do-and-mend if forced to........or wait for resupply, like everybody else.

 

I am looking to build the cabs based on the Faital Pro12PR320 neo drivers and the Celestion CDX1-1425 compression mid range, together with the  P Audio P-170 horn. From necessity, my builds will be from first principle, as I am too late for the flat-pack bus and Brexit has got in the way of sourcing a crossover kit. I am fairly competent with woodwork, having made kitchen cabinets and a few bass cabinets in the distant past. I am also fine with soldering and testing etc.; although by no means an electronics expert! I have a Vanderkey LNT212 as a point of reference.

 

I wanted first to thank those who have invested a lot of sweat-equity in seeing this project though, with obviously sucessful results. I also want to double check that the crossover diagrams now in the first post of this thread relate to to the build with the Faital/Celestion drivers? I plan to souce most of the non-woodwork materials from Europe Audio in Rotterdam.

 

From those who have already been down this road can I kindly look to you to give some helpful advice and stimulation as I set forth?

 

[stevie]

The diagrams are all still valid as long as you use the specified drivers and horn.

 

There are quite a few builders on here who will be happy to advise you if you get stuck. Don't worry.

 

The LNT12 is a fine cab and ideal as a reference.

[Phil Starr]

It was always our hope that these designs would last for many years so it is great that you are building this we hope that it will stimulate others to do the same. 

[BlueMoon]

On 19/12/2021 at 18:15, GlamBass74 said:

Crossover headache is looming. I'll crack it, but its my least fave part

@GlamBass74 : How did this work out for you? Before I start, I just wanted to gauge how this part went. Did you build it from scratch using independently sourced components and the crossover plan? One potential headache I see is being able to obtain crossover components that are close in specification, but not exact, and then not fully appreciating the impact any differences may have. 

[GlamBass74]

Hi Bluemoon

 

Well.... err......umm......errr...

 

Let's just say it's a work in progress

 

I have finished all the woodwork, painted the cab and I have all the components... I just haven't attempted the crossover yet

 

They're definitely my weak point. 

 

I really must pull my finger out and crack on with it as i'm sure it'll be a great cab!

[BlueMoon]

Totally understand.......I have a few projects in that phase!!

 

Grateful you continue to post the highs and lows of your journey! Very helpful for those who are following.

 

In the meantime, I'm busy sourcing components. That's another story, in current times. 

[osborne900]

I built one of these last year which turned out really great. The original horn and flare were not available so I ended up using RCF parts. I used a B&C crossover I had to hand which seems to work fine. I don't have any way to measure response so I'm not suggesting it's going to be properly FRFR but I've had plenty of favourable comments from others about how it sounds. I came across the Convair crossovers that Blue Aran sell which might be a decent starting place and are affordable. 

[Hacksawbob]

I've often wondered if there is such a thing as a variable passive crossover much like a tone control. But instead of rolling off the highs it rolls off the lows to a tweeter. I realise I'm showing my ignorance here, but I'm curious, wouldn't this give you far more leeway when designing a cabinet? There seems to be a lack of off the shelf availability which would suggest there's a good reason why this isn't more common, although you do seem to find variable passive tweeter filters on a few hifi speakers and some bass cabinets I believe. 

[paul_5]

Technically yes. 
 

You’d need some serious power rated components to do it, but in theory it’s more than possible.

[LukeFRC]

58 minutes ago, Hacksawbob said:

I've often wondered if there is such a thing as a variable passive crossover much like a tone control. But instead of rolling off the highs it rolls off the lows to a tweeter. I realise I'm showing my ignorance here, but I'm curious, wouldn't this give you far more leeway when designing a cabinet? There seems to be a lack of off the shelf availability which would suggest there's a good reason why this isn't more common, although you do seem to find variable passive tweeter filters on a few hifi speakers and some bass cabinets I believe. 

But these days a two channel amp and digital crossover would probably be cheaper. 

[Hacksawbob]

If you don't have an amp already it might be. 

[nekomatic]

On 28/07/2022 at 16:50, Hacksawbob said:

I've often wondered if there is such a thing as a variable passive crossover much like a tone control. But instead of rolling off the highs it rolls off the lows to a tweeter. I realise I'm showing my ignorance here, but I'm curious, wouldn't this give you far more leeway when designing a cabinet? There seems to be a lack of off the shelf availability which would suggest there's a good reason why this isn't more common, although you do seem to find variable passive tweeter filters on a few hifi speakers and some bass cabinets I believe. 

 

I don't think it'd be remotely practical to have variable components of the values you'd need for a crossover. Variable capacitors you can buy are in the 100 pF order of magnitude, and you need ones about 10 000 to 100 000 times bigger than that! You can simply attenuate a tweeter with a variable resistor, but you'll be changing the load that the crossover sees and that will change its frequency behaviour too…

 

…on which note, I asked about bi-amping rather than using a passive crossover in my own cab thread, and (I think it was) @stevie said it was certainly an option, but the interaction between the carefully developed crossover design and the dynamic behaviour of the speakers forms part of how the system behaves and therefore how the cab sounds. It'd definitely be interesting to try out the passive crossover versus bi-amping with the same enclosure and drive units - if anyone has the inclination and (ideally) the test gear…

 

@GlamBass74 which aspect of building the crossover are you apprehensive about? Can you solder ok?

Edited July 29, 2022 by nekomatic

[GlamBass74]

@nekomatic yep I can solder.

I love the woodwork, but crossovers hurt my brain 😁

 

This is the current state of my project

[nekomatic]

That’s looking good! Well worth finishing properly. 
 

I built the LF side of my crossover with terminal blocks and the HF side on matrix board, just soldering the component legs together. Get hold of the bits and start trying out layouts and it’ll make sense. 

[funkydoug]

4 hours ago, GlamBass74 said:

@nekomatic yep I can solder.

I love the woodwork, but crossovers hurt my brain 😁

 

This is the current state of my project

Wow that looks fantastic! Great work 👍

[GlamBass74]

Oooo an update! 

 

Thanks to the amazing generosity of LukeFRC, I've managed to progress with the bass chat cab. 

 

It's all together and ready for a test! 

 

Next stop is a grille and fit the badges and stickers that Luke also kindly sent me.

 

What is the next free serial number? 😁

 

I'll report my findings soon. 

[GlamBass74]

Me again.

 

I just played my "girlfriend test track" through the cab (street spirit fade out - Radiohead). I used a little shuttle 3.0 and an I pod.  

Once through the BC cab and once through a very new, expensive and very well regarded cab.

Yep.... Bass chat cab won.

More "even and full range" were her words.

I must say -it does sound great.

If you're sat on the fence about building one TRY IT.

I'm very impressed so far.

I'll update once the grille is completed and I've played a couple of gigs with it.

 

 

 

 

[Bassybert]

That looks so good, what a great job - It's definitely inspiring me to make a couple 😁

 

It's probably not even worth asking but would they function the same if I built 2 and stacked them one on top of each other laying horizontally instead of upright like this?

[Phil Starr]

11 hours ago, Bassybert said:

That looks so good, what a great job - It's definitely inspiring me to make a couple 😁

 

It's probably not even worth asking but would they function the same if I built 2 and stacked them one on top of each other laying horizontally instead of upright like this?

Would you need two? I've never taken two along to a gig and never needed to. The Faital 320 is a really nice driver, there are a few high end speakers using the Faital 300 and one or two using the 320. It has a really good excursion capability as well as a well-controlled frequency response. It can handle a lot of bass. On top of this the BC Mk3 uses a much higher quality Celestion horn driver than almost all other bass cabs and a sophisticated crossover so the mids are smoother, accuracy where you need it and no tizz. This is a top of the range cab

 

There are a few issues with stacking any 2 way bass cab. This one has been designed to cut down beaming caused by interference between widely spaced drivers. As soon as you introduce extra drivers you get interference between them called comb filtering. You can reduce that by getting the horns as close together as possible so vertically You'd have the top cab upside down. Stacked horizontally you'd have the horns vertically aligned. That would reduce the problems but not entirely eliminate them. 

 

These cabs have been engineered to help you hear all the frequencies equally well even when close to the cab. To avoid that experience you get live of it being very loud but you still can't hear what you are playing. Comb filtering would remove some of those frequencies so wouldn't help your experience as the bassist. It would of course be louder for the audience. 

 

Are you coming to the South West Bass Bash? You can try one of the Mk3's there.

[Chienmortbb]

@Phil Starr beat me to to it. When I built  the MK3, Iplanned to build a second cab. However after gigging the MK3 as a single cabinet, I realised that it was enough for me. It never really gets out of first gear. 
 

When I auditioned for my current band, I took the MK3 in and was asked “where is the rest”. They were obviously conditioned into thinking a bassist needed a stack. It has not been mentioned since. The real benefit if a stack is that you hear yourself better BUT the vertically aligned horn ensures that you can hear yourself even with the cab on the floor. Just as importantly, the dispersion of the horn will also help your band mates hear you better. 
 

As Phil says, come along to the Bash a week on Sunday and hear for yourself. @Phil Starris doing a cabinet shootout.