Mixing Folded & Ported Subs

[Rob_H]

 

Hi All,

 

I have added more gear over the last while and would like some input on mixing folded subs and ported subs; I went with 2 Peavey FHBX and 2 SP218BX as well. I have only done one show so far mixing them together with SP118BX's I already had; I clustered the 2-118 & 2-FB center on the floor and the room layout allowed me to run one 218 on either side of the stage on the floor coupled out against the side walls. In this particular venue it was a good combo with 2 SP6BX per side on stage and 1 SP3BX per side out with the 218's. I did set it up using the aux sub ideas discussed in the thread a while ago.

The room is a fair size conference room at a large hotel and would hold probably a max of about 600 people although there were only about 450 at the show. It was fully carpeted except for maybe a 40 x 40 temporary hardwood dance floor. They have a fabric wall covering as well so the room takes a lot of bass to get a good balanced sound. There was only one spot where the sound was a little off for balance but it was managable as it was in an area where the walkways where setup so only minimal "ear" time spent there by the audience.

I guess where I am more looking for input is on setups where this would not be a good mix and also where it is more practical to do it. I am also concerned a little about the efficiency difference and if it might cause some hair-pulling EQ spots, the FB are 108 db vs the 99 db of the 218/98 db of the 118. Everything is powered with Crest CPX 3800's, I ended up getting more of these as well.

As always, appreciate any feedback....I have heard they may not be offering the FB much longer in the same config so am considering getting a few more for down the road but would like to hear about any pitfalls first.

Thanks,

Rob

[agedhorse]

Mixing folded and front loaded ported subs is a poor idea in general. The phase response is totally different as is the delay (and group delay). Much better performance overall would be had with wither all one type or another.

Your comment about the folded horn sub being 108dB/1W/1M is patheticly laughable (not your comment, but the 108dB/1W/1M part) because if you look a the spec sheet you will laugh with me. This is a sub, it's intended to be used from say 100Hz or 90Hz on down, so looking at the spec sheet it shows a PEAK sensitivity of about 105dB at between 90 & 100Hz. Now look at 1 octave down or 50Hz, and you will see that the sensitivity is 99dB/1W/1/M. IF I was designing a DSP algorithem for this sub in conjunction with a suitable top, the first thing I would do is normalize the response between say 60Hz and 100hz pulling that peak down to ~100dB/1W/1M and bumping  the 40-60Hz response up a dB or so. The AVERAGE sensitivity over the sub band of say 40Hz - 100Hz is really about 100.5W/1W/1M.  But doesn't 108dB/1W/1M sound better to the marketing folks? Guess who won this aregument

http://assets.peavey.com/literature/specs/118016_14289.pdf

[Rob_H]

Thanks Andy,

Are there venues that lend themselves better to one design over the other? I grew up with folded, mostly W bins as that was the high tech of the time and any ported designs were very limited in both availability and performance. Prior to running everything together last weekend, I had only run them as seperate sub systems and the folded/SP3 combo works well but there are only 2 regular places I run that I can get away with something that small (they are also a lot easier to move around than the 118's). I found them a little easier to get to sound better than the ported but that may also be in my head just due to feeling "home" with the folded ones.

Thanks