stevie

Very good question. The answer is that you're quite likely to have impedance issues unless you know what you're doing. Here's an example of a commercial cab with serious problems in this area. It's not the first one I've seen either.

@Jolltax, .13mH will be OK.

I see Phil's answered your questions comprehensively. To save drilling holes (or using clamps) when you're assembling your cab, get yourself some self-drilling screws like those made by Reisser and others. Once the glue's dried, you can  unscrew them if they're a bit close to an outside edge or if you'd like to reuse them. A matchstick (with wood glue) is about the right size to fill the holes. Then dab on some wood filler and sand flat.

It doesn't get much cheesier than this.

2 hours ago, agedhorse said:

Ashdown DIDN’T get the volume so wrong. It was simply a design choice. 
 

By any chance was that tweeter ADDED to the cabinet in the existing port???

Interesting suggestion. If the cab originally had a port where the piezo currently is, that would explain a few things. Ashdown's literature says:

"Handmade in the UK, Ashdown introduces the ABM-NEO-210 Combo and NEO-115 combo and now a C110 1 x 10 combo, both the 210 and 115 are fitted with Ashdown high-frequency horns and custom Italian Sica Neodymium drivers..."

No mention of a tweeter on the 1x10. Unless they thought it best not to mention the piezo. The plot thickens. 

I can't find any photos of the cab with the grille off, but there are descriptions of the combo elsewhere on the internet that claim it has a horn. 

Mind you, that's all academic. Fitting a port to the cab will certainly improve its performance. And that's what matters to the OP.

I have to agree with the OP that cheap compressors are not up to much. I advanced from in-amp compression to a cheap Behringer then to a mid-priced Boss (forgotten the name) and didn't find either of them very useful. It was only when I got myself a Seymour Duncan Double Back VCA-based compressor that I was able to get the kind of 'thunk' I was looking for. 

I've been wondering why Ashdown got the cabinet volume so wrong. It looks to me like they specified the width of the cab to match the width of the amp, which is logical. I suppose they specified the depth of the cab so that the amp would fit in there too. Makes sense. And then they specified the height of the cab so that a 10- inch driver would fit with enough space for the grille surround.

 So that's how the professionals do it! 😁 (Present company excepted, of course).

The lack of a port remains a mystery. Especially as their published description claims it's ported.

I entered the Celestion Pulse 10 and the Sica driver into my modelling program and the Celestion performs marginally better in the 41-litre cab, but I'd persevere with the Sica rather than going out and buying a another driver. My software recommends a slightly longer port than @agedhorse. The standard length of the usual 100mm ports is 115mm. According to my software, that would tune your cab to around 52Hz, which would be fine. 

2 hours ago, JohnDaBass said:

What are the disadvantages of the port being too close to the corners?

Port midrange leakage, particularly of standing waves, is worst when you locate ports in the corner. They're OK for subs where you're not reproducing midrange frequencies. It's the same principle as locating your loudspeakers in the corner of a room. I avoid doing it. 

Looks like a 4" port will fit. It should make a big difference. Keep it as far away from the corner as you can. Was there any damping material in the box when you looked inside? Ashdown don't normally bother to fit any.  If not, it would be worth putting some in.

According to the Ashdown blurb, the C110H-400 combo is supposed to be ported. The Sica driver definitely belongs in a ported rather than a sealed box. Perhaps Ashdown forgot to put the port in the baffle.The only other explanation is that the tea boy designed the cab. 

The Sica driver is a decent budget driver and the Eminence would definitely be a downgrade. I think the OP's original idea was sensible. However, before anyone can advise on  porting, we really do need accurate internal measurements in order to work out the cabinet volume. I doubt that it's 55-60 litres. Is there space on the front baffle for a 4-inch port?

What make is the cab?

Angling and raising a cab does work if you want to hear yourself better, but it doesn't actually do what's needed, which is improving your cab's dispersion at mid and high frequencies so that you - and your audience - can hear those vital midrange frequencies clearly. When you point your cab at your ears, you only hear those midrange frequencies when you're standing right in front of the cab, because the cab's still beaming above 1kHz or so. As soon as you step to the side, you go back the muffled sound that everyone else - the rest of your band and your audience - is hearing.

The only solution is to have a cab with a decent power response. The only cabs I know of that deal with this issue properly are the Fearless 3-way designs - apart from the BCMkIII DIY design that @Chienmortbb referred to. Good quality PA cabs usually have a decent power response because their main job is reproducing midrange frequencies, although they have their own issues for bass guitar reproduction. 

As the OP said, this was originally mine. It's a tiny and powerful FRFR cab that's perfect for home and studio use but also works well as a high quality stage monitor. 

The crossover brings the level of the HF unit down to match the bass/mid driver and applies a high pass filter that matches the natural, upper rolloff of the bass driver. This is what virtually every bass cab manufacturer does. It's simple, it's easy and it's cheap.

Both the compression driver and horn are usable down to 2.5kHz, and that's where the system could be improved.

However, to get the two components to cross over at 2.5kHz, you'd need to filter the upper response of the bass driver, which means additional components. The circuit for the HF unit would also be more complex than it currently is. Chances are, you'd end up with three times as many components in the crossover, which  was not the aim of the project.

The Design Diary progressed from a Beyma SM212 on its own to a Beyma SM212 with a Celestion CDX1-1445 and P.Audio PH-170 horn - all ceramic magnets. The crossover for that system disappeared from Basschat when a particular  image hosting company closed down. Fortunately, chienmortbb has recently located the circuit in his files. So if anyone would like a copy - particularly @nekomatic - just ask.

We then went all-neo with a Faital Pro 12 and the Celestion CDX1-1425 -  again using the PH-170 horn.

Using any other components would mean a complete crossover redesign. The Celestion 1415 could in theory be substituted for the 1425, as they are quite similar. However, their sensitivity is different and you'd need to account for that in the crossover.

As far as inductors are concerned, there's an Ebay.uk seller who winds inductors to custom values in small quantities. The biggest European manufacturer of coils is a German company called Intertechnik, although I don't think they do custom values.

7 minutes ago, MOSCOWBASS said:

My experience with the GR AT210 compared directly with my 2x BFone10's shows the GR to be both louder and cleaner before breakup.

I don't doubt you in the slightest.

Man cannot live by in ears alone, grasshopper. 😁

If I were looking for a cab for slapping, I'd look very closely at the tweeter being used. Some makers - not very many - fit good quality tweeters to their cabs but most fit a generic cheapo Foster of P.Audio phenolic diagram bullet tweeter, which is awful and one of the reasons so many bass players turn them off.

Sad to say, no bass cab manufacturer fits a genuinely high quality HF unit. If you want one of those, you need to be looking at a PA cab.

When I lived in the north west, Salford was the place to avoid like the plague. Unless things have changed since the arrival of the BBC, that area probably accounts for the city's number one position.

38 minutes ago, mangotango said:

If you'd made that comment about someone from a different ethnic background, rather than a different regional background, it would rightly be regarded as racist.  It's no better for that.

 

You mean if he'd made a racist comment it would have been a racist comment. Too true. You seem to have missed the 'joke' bit. 😄

It will certainly be easier to hear yourself with the GR than what you currently have. So you may have found your solution. It'll be interesting to hear what you think anyway.

With a 10" Jensen and a bullet tweeter in the box, it's unlikely to be uncoloured either. A little puzzling indeed.

I can almost predict the way this thread will go.  I've been on Basschat too long. 😀

I have samples of both the Pulse 10 and the B10N-300X drivers. The Pulse has a bigger bottom end than the BN10 in this box but isn't quite as loud. Top end extension is about the same. Although there's a difference of 100W in the thermal power handling, the excursion capability (xmax) is fairly similar. So they should start to complain at about the same time.