Where to put ports?

[altec10]

Hi guys,
I posted some weeks ago of my intension to build a new pair of enclosures loaded with 604-HPLN's. I recieved an email from Richard Clark suggesting that I add a second driver. This is what I have come up with, the total volume of my bins will be 12 cuft split into two chambers. I'm thinking on 4 cuft for the 604's and 8 cuft for the second driver. The 604's I'll be using are Urei modified units with the blue horn and I was thinking of tuning them to 60 hz. The second driver I am looking at using is the new Eminence Magnum 18-LF 18" driver as this driver from what I can see will go down to 30 hz -3 db in the 8 cuft chamber. I would like to place the ports at the rear of the enclosures for asthetics reasons but my question is will the ports be better placed in the front baffle ?. Any advice on this would be greatly apreciated. A second question I have is does anyone have the T/S parameters for the 604-HPLN drivers and some crossover info that may help in connecting these drivers. I wish to run passive networks for a start with the abillity to bi-amp the system down the track. Thanks in advance.
Mike C.

[billfort]

I put the ports in my 604 cabinets on the bottom sides - I didn't want them in the front panel for ascetic reasons and because in the old cabinets you could get you ear close to the front port and hear midrange energy coming through. I think one of the advantages of the 604 is the point source design and having this second midrange source seemed best avoided. Not sure if this really made a difference but the cabinets sound very nice with this arrangement and the bass is incredible. I'm curious - have you heard the 604s on their own? Do you really feel the need for an 18 woofer? Maybe it's just me or my small room but I sure don't find these speakers lacking in the bass.

Billfortmy 604 cabinets

[Steve Burger]

Jim D is collaborating with Jerry Hubbard on improvement in the 604 crossover. Stay posted and we will let you know when it is available.

[jmarkwart]

Mike,
If you place the boxes fairly close to a rear wall, or in corners like Bill did, port location on the box makes little difference.
Jeff

[altec10]

Thanks for the replys guys, Billfort no I have not heard the 604-HPLN's yet but I have listened to a pair of 604-8g's in 620 cabs. I loved the sound of these but thought they were a little light in the bottomend. My last two systems have had JBL 2241-H's ( 18" ) and I just love the impact of these large drivers. I would love to use Altec 3182's but I'm not sure if they would work in 8 cuft bins.
Mike C .

[billfort]

Ah Mike! Your last system had 2 JBL 2241?s ? now I understand completely. Just so you know where I?m coming from, I progressed up to the 604s by originally liking Lowhters/SET (no bass), mini-monitors/SET (not much bass and mushy), 604-8Gs in rectangular boxes (yes!) and then the boxes I show on my webpage. Maybe it?s the corner placement, venting, baffle width, box construction, whatever, but I love the sound of these now and can?t imagine wanting more bass ? at times I think there might actually be too much (probably a room node problem).

Billfort