Does Size Matter? Is 8” Big Enough?

[Chienmortbb]

Of course I am talking of woofer size on full range tops. Long post so take a rest or tea break at regular intervals. 
 

I started thinking about this a while ago when @Phil Starrand I were working on my 8” extension cab. This was to complement my modified Ashdown After Eight combo. 
 

To cut a long story short, I started thinking about this in earnest when my band borrowed @Phil Starr‘s RCF Art 310As. Now I already had a pair of Whatfedale Pro Titan 12s plus two aging JBL 15” Subs. All were active and worked well together. However the performance of the smaller 10s in the RCF and the 8” speakers in my cab (the inspiration for the Basschat Easybuild 8” Cabinet) made me think (insert snide comments here). 
 

I knew from the 8” cabinet that a good 8” driver could go low enough and flat enough to work down to the point where a sub woofer could take over the heavy lifting. Indeed recent active speaker models from RCF,  Wharfedale and others have offered extended frequency response and what RCF call FIRPhase Whatfedale call just FIR. They both aim to maintain phase alignment at the crossover point between the woofer and tweeter. They offer 127/128dB max SPL peak (122/123dB real life) and the response extends below the 100Hz area where most subs take over. 
  
As I said earlier, I had used the RCF 310As (MK2?) and was impressed, so my initial thought was a pair of RCF Art310A MK4. A they are discontinued, and RCF did not make a MK5  10”version, I ordered a pair from my neighbourhood German Music Store. Thomann had bought RCF’s  remaining stock of the MK4 but all was not well. One was DOA so they both went back and a refund was offered. 
 

So, I looked around and Whatfedale Pro had added FIR technology to their Typhon Range. Although Whatfedale are now Chinese owned, the UK Arm still seems to do the R&D and like RCF, they make their own drivers. I love my Titan 12s so after much discussion I bought the Typhon 8 AXF and first impressions are favourable. The sound is well balanced and at just over 10Kgs reassuringly heavy for an 8”. Testing is ongoing and I will update later. 

 

[Chienmortbb]

As a gentleman of a certain age, neither me or my car is interested in hernia inducing 15/18” subs. So my interest was piqued when @Happy Jack started his small, lightweight  sub quest. After receiving many recommendations, he found the Citronic Casa 10BA. Having sold my JBL subs, I had a few groats to spend and ended up being the owner of one. I was firmly bitten by GAS now and after hearing it, ordered a second.

 

I had a hernia operation on Sept 2nd so we had kept the diary clear and close to the end of my 6 week “ no heavy lifting” spell, I developed a rotator cuff injury to my shoulder so no real world resting, even in rehearsals. I will report back later when I have more. 
 

So earlier in the year, I had no intention of buying a new PA and a pair of 8” tops and 10” subs were not even considered. While they would not do a really big gig, for the  pubs clubs and parties we do, I am sure they will be more than enough. 

[Phil Starr]

I'm really interested in seeing how this turns out John. I've played with a couple of 8" tops with a decent sized sub when we did a spot at an open mic in Wokingham. I think the tops were a couple of Alto's. In a typical sized English pub they were appropriately loud, vocals were well handled and everythind sounded as it should. The house band sounded fantastic and this was with live drums, albeit a modest sized kit.

 

I see no reason why this sort of set up shouldn't match one of the modern 'stick' systems which often have a 12" or even 2x8" dedicated sub. The 8" tops will be more directional but that could mean that the sound is thrown further, so which works best would depend upon the venue.

 

You aren't too far from me so it would be good to come out and see how you get on.

[Bill Fitzmaurice]

An eight loaded top is sufficient for pub gigs, provided the woofer is of high quality. The same applies to eight loaded subs. The trick lies in knowing the quality of the woofer, as manufacturers are loathe to reveal what they're loaded with. 

Quote

The 8" tops will be more directional but that could mean that the sound is thrown further, so which works best would depend upon the venue.

Eight loaded tops are less directional, as the angle of dispersion is inversely proportional to the size of the cone/radiating plane . As to throw, the inverse square rule applies to all driver sizes. The advantage to 'stick' systems is they have very wide dispersion on the horizontal plane, due to the smaller driver sizes, along with narrow dispersion on the vertical plane, due to the taller radiating plane. That aims more sound into the audience, less at the floor and ceiling. The disadvantage is most use woofers too small to do the job, at an unjustifiable price. A very good arrangement is a 2x8 top, which can give output equal to a 1x12, with wider horizontal dispersion and narrower vertical dispersion. The same applies to 4x6.5 inch tops. But those are few and far in between, as their advantages are very much unknown to the average user.  

[Phil Starr]

2 hours ago, Bill Fitzmaurice said:

Eight loaded tops are less directional, as the angle of dispersion is inversely proportional to the size of the cone/radiating plane .

I''m surprised at you Bill. You'll be aware that the idea is to crossover to a horn which determines the radiating pattern in the midrange and not the woofer. Above the crossover area the size of the woofer is largely irrelevant. That is as opposed to the 2,3 or more rarely 4" speakers in the columns which as you say have a wide dispersion in the horizontal plane. I can't think that you really believe that those 2 mor three inch speakers in a column would outperform the horn in a point source speaker. 

 

Perhaps to make things a bit clearer I shgould clarify. John's speakers will have a similar output to many of the stick systems like the RCF J8 and similar speakers. The dispersion of these different design approaches are that the columns spread the sound widely in the horizontal plane and the point source speaker with subs will radiate over a narrower area, typically something like 90x60. In some rooms the advantage might be to the point source speaker and in others to the column. The horns in the Typhon are 100x80 so are pretty much designed for near field but still more directional than one of the 'sticks'.

[Bill Fitzmaurice]

I was referring to the dispersion of the woofer, not the high frequency element. One of the main shortcomings of many twelve and fifteen inch loaded PA tops is they tend to cross over to the HF element at too high a frequency, which should be no higher than 1.2kHz with fifteens, 2kHz with twelves. Those that do get it right tend to be in the upper price range.    

Edited 1 hour ago by Bill Fitzmaurice