Basschat 2x12

[Chienmortbb]

Well like @Phil Starr I have used both the Beyma SM212 and the Faital Pro PR320 and gigged extensively with both. The SM212 has more low end in the BC212 Mk3 cab and on the face of it is a better driver BUT in many venues the bass had to be turned down and in that cabinet the Faital Pro is probably the better bet. The faital Pro does have a weight advantage as well. Of course you can turn the bass down as I said. I suspect that the Beyma would work well as a sub in a 70-80 litre cabinet but I have not modeled it.

Edited July 25, 2022 by Chienmortbb

[RichardH]

51 minutes ago, stevie said:

Despite the weight, it is actually a neo driver, Richard.

Blimey!

[Stub Mandrel]

On 21/07/2022 at 23:03, Phil Starr said:

OK this is the frequency plot for 4 speakers. The Kappalite used by Barefaced (red) Beyma Sm212 (blue) Deltalite (purple) and the Faital 320 (green) all in the same cabinet 50litres. You know what the Deltalite's sound like so that gives you a starting point. They have a peak around 120Hz of about 2db which is colouring the bass and the bass rolls off slowly from there. The Beyma has a similar peak slightly les high than the Delta's but has the highest output at 40Hz of all the speakers. The FAital has the highest peak of all, around 3db and the highest output between 50-100Hz. the interesting one is the Kappalite with the most powerful magnet it has the flattest response down to 70Hz and then rolls off more quickly that the other speakers. Remember this is just the bass response up to 200Hz so not the whole picture.

 

Remember these are all in the same box, they can all be put in different boxes, the beyma would love a larger box and the Kappa would be better in a smaller box, or i can tune the boxes differently and shape the curves a little. Despite this I think it is fair to say the Beyma is going to have the deepest bass and the Kappa is going to be the most honest speaker with all the rest tending towards warm sounding.

 

Is this unported?

[Phil Starr]

all ported in 50litres and I think tuned to either 60 or 50Hz, my computer crashed and i didn't save the files.

 

I do a lot of this when selecting drivers. In the olden days I'd have standard cabs and just swap speakers now I usually start with a 50l cab for 12's and a 30l cab for 10's and computer modelling which lets you cover a lot of ground. you can tell pretty much from the T/S parameters what you expect but it's really easy to see the graphics. 

 

Once I've got a driver selected I'll tweak the cab volume and tuning but you can only move the envelope so far. 

[stevie]

7 hours ago, RichardH said:

Blimey!

Indeed. It would weigh over 10kg if it had a ferrite magnet.

Edited July 25, 2022 by stevie

[Phil Starr]

OK I've managed to grab a few minutes and I'm looking at the Faital 320 as the speaker to beat.

 

So I'm looking at tuning first I can shape the response by tuning the port to differing frequencies, in this case gold is tuned to 45Hz and the purple to 55Hz. Tuning higher gives the raised hump at 90Hz and the lower tuning gives an almost flat response. For me a 3dB hump is just too warm and woolly 1db is just noticeable so 2dB is kind of where I'd like it to sit. But, it isn't just the response that is affected. The software is adding the output from the port and the speaker itself and when th port is active it is damping the movement of the speaker. That in turn affects power handling.

 

 

So this graph shows the power handling. You can see the power handling is restored to the full 300W of the thermal limit where the ports are tuned at 45 and 55Hz in the different tunings. The dip above this is because the speaker excursion is beyond the limits the speaker can handle. What's going on here is the coil is moving outside the safety of the magnetic field. So at 70Hz the power handling is reduces to 120W at the lower tuning. I'm going to be looking at every aspect of the speakers behaviour even though I'm going to be talking about bass response most of the time. I might come up with a recommendation that looks sub optimal but in the background I'll be trading off gains in one are against a cost somewhere else. Speaker design is a bit like squeezing a balloon. Solve one problem and another one pops up elsewhere

 

[JPJ]

Fascinating stuff, thanks again Phil for taking the time to look at this for me.

[Owen]

I bought an ACME 1x12 a long time ago. The cab was appreciably bigger than the "standard" 1x12. For me, the box "breathed" all the way down to bottom B and it was joyful. Is there any milage in making a bigger box? While I am asking speaker questions, the RCF 745 cabs get a lot of love. I believe that they have the mother of all compression drivers and cross over at 600hz to a 15". Obviously, bi-amping is going to help and that turns it into a whole different thing. Would it be something which would work with a passive crossover? I have NO plans to do anything of the sort, it is just a question I have been pondering. 

[Chienmortbb]

4 hours ago, Owen said:

I bought an ACME 1x12 a long time ago. The cab was appreciably bigger than the "standard" 1x12. For me, the box "breathed" all the way down to bottom B and it was joyful. Is there any milage in making a bigger box? While I am asking speaker questions, the RCF 745 cabs get a lot of love. I believe that they have the mother of all compression drivers and cross over at 600hz to a 15". Obviously, bi-amping is going to help and that turns it into a whole different thing. Would it be something which would work with a passive crossover? I have NO plans to do anything of the sort, it is just a question I have been pondering. 

I happen to know that @Phil Starrhas just acquired a pair of RCF 745s, over to Phil...

[Phil Starr]

Outed

 

[Stub Mandrel]

Is there a Basschat 1x10? Struggling to choose a 4R driver.

[nekomatic]

14 hours ago, Stub Mandrel said:

Is there a Basschat 1x10?

There is

Edited July 30, 2022 by nekomatic

[Stub Mandrel]

7 hours ago, nekomatic said:

There is

 

Thanks  i thought so, but couldn't find it with the obvious searches.

[Phil Starr]

Last graph for a while

 

This one shows the Faital 320 in three different sized boxes. The pink is the 50l box, red is 85l and green is 35l. This time the boxes are tweaked to get the 'best' out of each box. What you see happening will be true of any speaker put in different box sizes in general terms. The larger box allows the best bass response in that it is flatter and goes down lower. 85l is about perfect for this speaker in that respect. -3db is well below 50 Hz  and -10db which is what most manufacturers quote is pretty close to the fundamental of bottom B on a fiver. Putting any speaker in  a smaller cab introduces the bass hump and the smaller the cab the higher the frequency at which it happens. It doesn't show well in this graph but the peak gets higher too.

 

The thing is that for a bass cab more bass isn't really a universally good thing. Our ears don't pick up sub100Hz very well but mics do so the vocal mics will amplify this bass even though we can't really hear it and the PA will quickly start to struggle. (use the 80Hz filters guys) If you are stuck in the corner those bass frequencies will be boosted and you might well start to excite room resonances. In listening tests we carried out with bass players most bassists thought the pink response was 'bassiest' not the red one. Only about one in three recognised the extra deep lows of the red response. That is bass players, most of humanity gets bass information from the second harmonic in the signal 80-160Hz.

 

So now the question. How big do you want the cab to be? Given the trade off. I can give you the Pink response in a 100litre 2x12 using this lightweight value for money driver. I can get an extended response in a smaller box by using a speaker with a bigger magnet. Or I can get the box size right down with the pink response with the right driver if I can find one. A 100l 2x12 isn't huge but it is substantial, a few years back it was around the norm but with cheap drivers and for me a bit too much of a warm sounding hump. If you leave me to it I'll design around the Faital 12PR320 and try and optimise size and response but I think physics will push me to an 80-100l cab. If you want something smaller I'll look for another driver, though the perfect driver can be hard to find.

 

 

 

 

 

[JPJ]

So regarding size, this is going to be a single cab solution to all my gig needs, therefore I am not looking for ultra small or lightweight. Playing around in Excel, I think its going to be really difficult to be below 100 litres and stick with a finished width of 520mm to accommodate a 19" rack head in rack case without overhang (my OCD can't do overhangs 🤣). So width is fixed, height is dependent upon getting two drivers plus port on the baffle and depth is going to be whatever it is without the whole thing being unstable.

[Phil Starr]

That's great, it means your cab is almost designed. the original Basschat Mk1 1x12 was designed for a 19" amp so basically you'll be getting two of those. If I remember it weighed about 11kg with ceramic speaker magnets. Yours should come in well under 20kg with the bigger cab but lighter drivers.

[JPJ]

3 hours ago, Phil Starr said:

That's great, it means your cab is almost designed. the original Basschat Mk1 1x12 was designed for a 19" amp so basically you'll be getting two of those. If I remember it weighed about 11kg with ceramic speaker magnets. Yours should come in well under 20kg with the bigger cab but lighter drivers.

Woohoo! I can cancel my gym subscription then 😂

[warwickhunt]

So you are going to build this... but 9cm wider?    

[JPJ]

Yes @warwickhuntbut with a difference, my speakers will be in a line as my OCD couldn’t take that either 🤣

[warwickhunt]

43 minutes ago, JPJ said:

Yes @warwickhuntbut with a difference, my speakers will be in a line as my OCD couldn’t take that either 🤣

 

That is the correct answer!  I've no idea why all of these vertical 2x12s have the speakers 'slightly' off-set; it has no aesthetic or acoustic advantage!  

[Chienmortbb]

1 hour ago, JPJ said:

So regarding size, this is going to be a single cab solution to all my gig needs, therefore I am not looking for ultra small or lightweight. Playing around in Excel, I think its going to be really difficult to be below 100 litres and stick with a finished width of 520mm to accommodate a 19" rack head in rack case without overhang (my OCD can't do overhangs 🤣). So width is fixed, height is dependent upon getting two drivers plus port on the baffle and depth is going to be whatever it is without the whole thing being unstable.

I had a size issue when I modded my Ashdown After 8. It needed a port but there was no space on the front baffle. The amp was taking up most of the back so I mounted the port on one side. Of course you have to be careful not to put the port next to a wall.

[Phil Starr]

It'll be a slot port as requested on the bottom of the cab.

 

I don't like narrow slots so the barefaced vertical port is not ideal IMO, even if it looks aesthetic. That makes this a tall cab and with the 19" top it more or less designs itself. I only need to find an hour or so to fiddle with volumes and tunings and the design work is essentially done.

 

Edited August 2, 2022 by Phil Starr

[Chienmortbb]

7 hours ago, Phil Starr said:

It'll be a slot port as requested on the bottom of the cab.

 

I don't like narrow slots so the barefaced vertical port is not ideal IMO, even if it looks aesthetic. That makes this a tall cab and with the 19" top it more or less designs itself. I only need to find an hour or so to fiddle with volumes and tunings and the design work is essentially done.

 

Ah yes I forgot about the slot port.

[Phil Starr]

OK we have a design, c100litres with a slot port at the base of the cab. Using two Faital 320's 83cm H, 51cm W and 36cm D. The port is 6cm high and 19cm long. i've tuned it to reduce the bass hump to just 1db and managed to extend the bass so -10db is 41hz. Coincidentally that is bottom E. Internally the dimensions are 80x48x30cm. Sensitivity is 98db/w and it should achieve a slightly scary 126db in real money. 

[GlamBass74]

@Phil Starr - Phil, can I ask how you determined the port length? 

 

Did you use something other than WINISD?

 

My last two shelf port attempts have been "interesting" with regards to port length

 

Cheers