Celestion Pulse XL 10.40 Cab

[David Morison]

You're welcome.
Those generalisations are broadly right for the frequencies, but a lot of it is dependant on individual playing styles etc.
There will certainly be some content above 5kHz in say, a bright modern slap sound, but I think that's quite different to what you said you were into.
Indeed, for players using much drive/grit etc, lots of extension at the top end can actually sound unpleasant - it can end up sounding artificially "fizzy" for want of a better, subjective description.
(How many times have you heard: "I wish that Ampeg 810 had a tweeter in it!".... Yeah, me neither ) *
If rocky, drive based sounds are what you're going for, be prepared to play with the pad control to tame it a bit.

As for power handling/risk of damage, letting the tweeter play lower frequencies by using a higher value of capacitor increases its risk by two mechanisms: 1; by asking it to cover a wider bandwith, it's simply doing more work, so its average share of the power will be higher and 2:, the lower in frequency we require any driver to play the more its diaphragm has to move forwards & backwards, and tweeters in particular can't move far at all.

In your application (only paired with one, fairly low efficiency 10"), it'll probably be pretty hard for you to blow the tweeter - it will hopefully have been made with the whole gamut of bass guitar rig applications in mind, maybe even on up to retrofitting fridges, so you shouldn't have to get too concerned with how much level you can afford to give it for any given cap value.

* Yeah, I know there have been some 810's with tweets, but I'm willing to bet they're a small minority overall.

PS, Any Englishperson cognizant of their need for regular apologies is obviously one of the more enlightened few of that species, therefore alright by me.
Sincerely,
Your friendly neighbourhood Scotsman.

 

[LeighOnSea]

You're welcome.
Those generalisations are broadly right for the frequencies, but a lot of it is dependant on individual playing styles etc.
There will certainly be some content above 5kHz in say, a bright modern slap sound, but I think that's quite different to what you said you were into.
Indeed, for players using much drive/grit etc, lots of extension at the top end can actually sound unpleasant - it can end up sounding artificially "fizzy" for want of a better, subjective description.
(How many times have you heard: "I wish that Ampeg 810 had a tweeter in it!".... Yeah, me neither ) *
If rocky, drive based sounds are what you're going for, be prepared to play with the pad control to tame it a bit.

As for power handling/risk of damage, letting the tweeter play lower frequencies by using a higher value of capacitor increases its risk by two mechanisms: 1; by asking it to cover a wider bandwith, it's simply doing more work, so its average share of the power will be higher and 2:, the lower in frequency we require any driver to play the more its diaphragm has to move forwards & backwards, and tweeters in particular can't move far at all.

In your application (only paired with one, fairly low efficiency 10"), it'll probably be pretty hard for you to blow the tweeter - it will hopefully have been made with the whole gamut of bass guitar rig applications in mind, maybe even on up to retrofitting fridges, so you shouldn't have to get too concerned with how much level you can afford to give it for any given cap value.

* Yeah, I know there have been some 810's with tweets, but I'm willing to bet they're a small minority overall.

PS, Any Englishperson cognizant of their need for regular apologies is obviously one of the more enlightened few of that species, therefore alright by me.
Sincerely,
Your friendly neighbourhood Scotsman.

Thanks again for the very clear explanation
I'll play with the Pad setting but I suspect it will end up being set low

PS I am genetically quite North of the Border, being a Sutherland, and even, as a boy anyway before it started turning white, making Ron Weasley look merely Sandy. One day I'll get up there, its No 1 on my bucket list, but Poruguese Wife says 'No!'

 

[6thplanet]

Yes, as David described. Even using the 3uF cap will be fine.
From positive of woofer or input jack to the cap, out of cap to input of L-pad. Output of L-pad to tweeter positive. Negitive of tweet to common on L- pad also connected to negitive of woofer or input jack. Tweeter could also need to be connected reverse phase, but again without measuring equipment, Try it either way, let your ears decide.

 

[LeighOnSea]

Yes, as David described. Even using the 3uF cap will be fine.
From positive of woofer or input jack to the cap, out of cap to input of L-pad. Output of L-pad to tweeter positive. Negitive of tweet to common on L- pad also connected to negitive of woofer or input jack. Tweeter could also need to be connected reverse phase, but again without measuring equipment, Try it either way, let your ears decide.

Thanks!

I will start with the 2 uF cap
Possibility of tweeter needing reverse phase is simply swap plus and minus as I understand it (I am not scared of stupid questions, obviously )

So, after some research, in terms of the connectors on the physical L-Pad, like this?
EDIT: I am going to start using the word 'Configulation'!

(https://www.madisoundspeakerstore.com/images/ft17h-config.gif)

Where any numbers on the L-Pad contacts read 3, 2, 1 from left to right in the diagram above (I read that numbers on components are in order when viewed from rear as that's normally how you put them in)

Numbering seems to agree with photo here (remembering that L-Pad is other way up in this photo):
https://www.talkbass.com/threads/wiring-this-l-pad.1203690/

I am thinking of moving the input jack from the side at the front to the back (I did it like that to enable the cab to sit flush against wall, but this is now not required) to the back. Actually, rather than removing the front one and filling hole I think I would rather just wire in a second jack in parallel. I can see no reason not to, but would just like to check. OK or NO OK?

I might have scavenged a real bass head to drive this thing from a mate

 

[LeighOnSea]

Yes, as David described. Even using the 3uF cap will be fine.
From positive of woofer or input jack to the cap, out of cap to input of L-pad. Output of L-pad to tweeter positive. Negitive of tweet to common on L- pad also connected to negitive of woofer or input jack. Tweeter could also need to be connected reverse phase, but again without measuring equipment, Try it either way, let your ears decide.

And your phase inversion comment got me thinking.
All the below are just my thoughts, I could be and am usually completely wrong, I'm just asking if its like this to satisfy my burning curiosity and to learn.
I presume this is due to the cap?
Link Removed
1/4 phase shift because current is 1/4 phase behind Voltage? (Sailor's Analogy: Tidal Height = Voltage, Tidal Stream (current) = Electrical Current, so max current when voltage increasing at max rate, min current at high or low tide 'dead' water)
But that is for a simple cap on its own, not with L-Pad
Link above says phase increased by decreasing frequency &/or increasing capacitance, cant do anything about frequencies (of which there are many, so presumably the phase shift is different for highs and lows?) but can keep cap low to give less phase change?
Or maybe, for this specific case of a specific type of case here, its best to increase the unavoidable phase shift to get it to half phase and then nullify it by swapping polarity?
Impractical / difficult to try to work out which approach to take, Hence the 'stick the thing in and see how it sounds' advice? Which is what I will do, I'm just curious

 

[6thplanet]

Yes, you diagram above is the way you'd connect the cap/L-pad.

As for polarity, yes the cap does induce a phase shift, but it also has to do with relative phase of the woofer and tweeter as they interact around the crossover frequency region. Also, yes, reverse phase or polarity is just swapping the connection to the tweeter.

 

[agedhorse]

Don’t get too deep into the weeds worrying about the phase shift due to the cap. There’s plenty of other things to worry about that are less trivial. The cap is only one small aspect of the introduction of phase shift between the elements.

 

[LeighOnSea]

Don’t get too deep into the weeds worrying about the phase shift due to the cap. There’s plenty of other things to worry about that are less trivial. The cap is only one small aspect of the introduction of phase shift between the elements.

Thanks! Sensible advice

the grill, corner protectors and handle came today.

I decided to leave off the corners, since routing would have got complicated without relocating screws, and its easier and I like the simple look more.

Similarly with handle, but also my markbass wont sit on top nicely with that on.

I didnt have any black screws for the grill and thought I would change them later, but I quite like it with the silver ones. And path of least resistance and all that

Photos below unclude two 'mock ups) with corners and handle which I decided not to pursue.

Tweeter etc arriving end this week. I just need an 80 mm hole saw (not really space to use router at corner of cab and hole saw good enough there I think as hole edges hidden).

 

[LeighOnSea]

Don’t get too deep into the weeds worrying about the phase shift due to the cap. There’s plenty of other things to worry about that are less trivial. The cap is only one small aspect of the introduction of phase shift between the elements.

Thanks! Sensible advice

the grill, corner protectors and handle came today.

I decided to leave off the corners, since routing would have got complicated without relocating screws, and its easier and I like the simple look more.

Similarly with handle, but also my markbass wont sit on top nicely with that on.

I didnt have any black screws for the grill and thought I would change them later, but I quite like it with the silver ones. And path of least resistance and all that

Photos below unclude two 'mock ups) with corners and handle which I decided not to pursue.

Tweeter etc arriving end this week. I just need an 80 mm hole saw (not really space to use router at corner of cab and hole saw good enough there I think as hole edges hidden)

 

[LeighOnSea]

I could only get a hole saw of 83 mm for the tweeter cut out (data sheet says 80 mm diameter), which I think must be OK, 1.5 mm (just under 1/16") each side cant make much difference can it?
Sorry for double post above, was on my mobile / cell phone

I think I'm going to rout the edges and put those corners on, bugger it!

 

[David Morison]

You might get away with that larger hole saw, but the best thing would be to wait till you have the tweeter in your hands and measure it before committing.
That way you can check that there will still be enough overlap between the front flange of the tweeter and the baffle to make a good seal, and that your cutout doesn't get too close to the mounting holes.

 

[LeighOnSea]

Doesnt look like it will be a problem
But I ordered an 80 mm hole saw anyway.

 

[agedhorse]

It’s another non-problem.

 

[LeighOnSea]

Edges routed. Needs a repaint now and then corners fixing on. I think tweeter just arrived

The L-pad and capacitor are much bigger than I expected

 

[agedhorse]

You have the corner on backwards.

 

[LeighOnSea]

Intentional mistake to keep everyone on their toes.
I will screw them on proper.

 

[LeighOnSea]

 

[LeighOnSea]

Just waiting for tweeter to arrive now

 

[LeighOnSea]

Intentional mistake to keep everyone on their toes.
I will screw them on proper.

I joke, but thanks for the advice, I did wonder initially

 

[David Morison]

Looking Good!