Rockford Fosgate Punch sub question

[audiomachines]

hello everyone,

I have two RF Punch rfz1412 sub and I want to build vented enclosure for it, problem is that the manufacturer suggested that it would be a 2 cu.ft. enclosure tune around 35Hz, but when i ran a WinISD simulation on it the plot tells me that there would be a +3dB hump on the 50Hz 60Hz area, WinISD suggest that it would be an 8cu.ft enclosure tune around 22Hz so that it will be flat down to 20Hz (to large for me). now I'm confused which one should I build? if I build the 2 cu.ft. enclosure and a Linkwitz transform ckt. can i achieve those 20Hz extension? comments and suggestion would be greatly appreciated thanks and a good day

regards,
audiomachines

[Big Kev !]

What the manufacturer recommends is only a suggestion, its not nessecarily what you have to build or would want to build. Most people putting subs in their car (especially from a brand such as RF) want loud punchy bass and arnt to concerned about SQ. As your doing, most people who care about it or know what they want will either model the sub and make something for their needs - or tell an installer/shop what they want and if they're any good thats probably what they'll do. (thats not to say all manufacture suggestions are bad though)

My brother built his DD sub based on their recommened designs and it has a very large peak and combined with his bass boost on his amp this peak is somewhat extreme. From a SQ perspective (or I suppose my perspective, what sounds good is in they eye of the beholder) its absolutely shocking. I've watched movies with it with some mates and we laughed because the bass at certain points was rediculously over the top it just sounded silly. For music, personaly, I didn't like it , but my brother loves it. If your into a lot of dance sort of music or really anything with a bass drum beat and you like to sit in your car and feel it pound in your back and not hear much else then yes its good, its a bit like clubbing in your car. Very good for impressing your mates and for 90% of people (who don't come on the internet to dicuss such things) its enough. I have to admit sometimes I like that whole feel but I'd prefer to have something a lot smooth and have the headroom to use the EQ to get the same effect, but obviously nothings for free

One question is this for your car or in your house? I've personally found getting SPL and getting nice extention to ~20Hz is a lot easy in your car because of cabin gain. Some of the subs I've been trying the last few days in my room and in my car, in the same enclosure sound very different.

[audiomachines]

hi,

thanks for the reply, it would be a home sub, it would serve as a sub for my KEF K120 which by the way has a very fast, tight bass 'really musical' to bad it only goes down around 65hz because of the 1st order higpass at the woofer crossover (to protect the woofer from bottoming just like the Genesis 1) and what else can you expect from a 6'' mid woofer , I had also a home built sub with 2 JBL 2226H but it wouldn't go down below 40hz. I want to my sub as flat as possible, I mostly listen to orchestral music.

regards,
audiomachine

[nunayafb]

I mostly listen to orchestral music.

This tells me you probably dont need it flat to 20hz, I would suggest targeting an f3 in the low to mid 30s.
I modeled it in 5ft^3 tuned to 24.12hz and the f3 was at 27hz with inaudible group delay(based on studies of audibility of GD at 20-30hz...). This f3 should make you quite happy and with some room gain should get you decent low end extension.

I have 2 RF woofers and both of them say it can go into some ridiculously small box, they cant. You have to multiply all of their box recomendations by 2-3 if you care about SQ at all, this seems to hold true for all of their woofers though technically I've only modeled 5 or 6

[audiomachines]

hello nunayfb,

Thanks for the reply. I can live with that 5 cu.ft. enclosure . so it would be two 5 cu.ft. enclosure for my RF subs. I'll be hacking my MDF's this coming weekend. By the way while your at it. I also have 2 RF SPP-188 18'er I had no info about its T/S parameter. Many thanks and have a nice day.

regards
audiomachine