Is there any benefit from woofers exceeding 5 inches, if matched with sub?

[detlev24]

[...] I checked my AVR specs. The filter characteristic says
Filter Characteristics
(fc=40/60/80/90/100/110/120/160/200 Hz)
H.P.F. (Front, Center, Surround, Surround Back).......12 dB/oct. L.P.F. (Subwoofer) .....................................................24 dB/oct.

So I should the above in minidsp right? This should be my task during Christmas break [...]

As I mentioned, the main issues in your system are 1) room acoustics and 2) subwoofers' integration.

The options of your AVR are a bit restricted but this just means that you have to experiment a little more to find the optimum tuning in your room.^^ It seems you only have five options to choose from within the range of interest; regarding crossover frequency (fc): 80 Hz, 90 Hz, 100 Hz, 110 Hz and 120 Hz. Values in-between seem not be available.(?) It would be perfect, if your room modes enabled the use of one of these - precisely.

The filters are most likely Linkwitz-Riley... there is no information about this, right? So, you would set the HPF [12 dB/octave] for the main loudspeakers on your AVR and the best fitting one as LPF [determined by in-room measurements; as 12 dB/octave HPF would unfortunately not add to an anechoically linear frequency response, unless LPF polarity is inverted, see some examples below] on the '2x4 HD' (this would allow further FIR filter application to linearise crossover). You would therefore disable LPF for the subwoofer channel(s) on your AVR. If not possible, set it at the highest frequency [= 200 Hz]. Especially at "only" 12 dB/octave filter settings, it is beneficial to crossover as closely to 120 Hz as possible [so the 8340A wouldn't have to reproduce much deeper notes].

If your optimum crossover frequency does not fit any of the 5 available options: just experiment with different combinations - take measurements - and choose the best one in the end. The results should be quite decent, if time-alignment to your main loudspeakers was done properly.

As I previously noted, you could then add further room EQ: automatically - or manually, to refine the full-range frequency response at your listening position(s).


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[Plcamp]

Just my opinion, not entirely fact based, but I do think I am right here...

The thing that matters is the product of cone area and excursion. Choose your weapon.

I use dual neodymium 15” woofers up to 700 hz just to be able to cross into an 8” fullrange so that fullrange doesn’t need large excursion ( less than 1 mm) ..and therefore has low distortion. Neodymium matters because you need a very powerful motor to control a big 15” cone at that high a frequency. I want to power my fullrange with a high quality first few watts, not burden it with bass frequencies that demand exponentially higher amp power and cone excursion. I think this is critically important for fullrangers.

I use a paradigm powered sub 50 hz down, dual OB 15” up to 700, and an 8” fullrange for the rest.

I don’t trust high excursion as a means to achieve spl. Many others argue pro-large-excursion. In subwoofers filling 50 hz and below I am ok with big excursion woofers. At stereo frequencies (above about 100 hz) I want low excursion.

I am filling a large room with up to ear damaging spl at low distortion. Your needs might be quite different? I am listening at a 15’ distance. I power my 15{s with a Hafler XL280 (a beast granting huge bass headroom) and biamp the fullrange using an Adcom 535II dual mono power amp.

I am thrilled every day. It really sounds great.

 

[SteveF]

Hi may be late to this party but two things to consider in the issue of smaller midwoofers is how much excursion a specific driver is capable of with low distortion as moving air determines spl and bass output and two, larger drivers with deeper cones can cause diffraction effects on vocals and other instruments that change tonality or color

Intermodulation issues can occur when larger drivers wander too far into the midrange