'Perceive' Contruction Diary

[Jim85IROC]

You may want to consider a TC Sounds TC2 or TC9 10" woofer. Those drivers have a great reputation for being very clean, accurate, low distortion woofers. They also have a high x-max and high power handling. The only potential drawback may be whether they have a clean response up to 500hz, and what kind of cone breakup there is. As long as the breakup can be managed and their bandwidth is suitable, I think they would be a great candidate for a LR transform.

[ShinOBIWAN]

Right update time.

After much time researching I've eventually settled on 6 x Sea's L22 RN4X/P. Not the most exotic choice considering the partnering drivers but after working through many variables including cost these are my final choices.

Three drivers per cabinet working in a sealed box of ~60ltr(after bracing and driver displacement. Front baffle will be 38mm thick.

I've taken up Scott on his advice and decided on some thing that will go low hence a Linkwitz transform for flat response to 20hz.

Have all the MDF so after I've run the drivers in and then tested them in SW, I'll tweak the box and LR circuit as nessecary.

So now all the major decision's have been made its just a case build, test and tweak.

Pictures will of the first stages of construction will be up very soon

Getting excited now!

[wigginjs]

You aren't the only one getting excited =).

[ShinOBIWAN]

Outline of the final enclosure design:



Total dimensions are(WxHxD): 30 x 110 x 51cm

[tiroth]

At the risk of sounding like a third grader: no fair cheating.

It's a little scary really.

[ShinOBIWAN]

Originally posted by tiroth
At the risk of sounding like a third grader: no fair cheating.

It's a little scary really.

You design good Tiroth

Seriously though I based my speakers on the Von Schweikert VR-4SR:



I'm not keen on the veneer so I'll probably get the cabinets into a spray shop for a real nice gloss black finish

[pinkmouse]

That's quite a steep slope on the mid-hi box. Have you checked the dispersion on the tweeter, ( I know the ATC will be fine )?

You might also have some crossover lobing issues if you are not careful...

[ShinOBIWAN]

Originally posted by pinkmouse
That's quite a steep slope on the mid-hi box. Have you checked the dispersion on the tweeter, ( I know the ATC will be fine )?

You might also have some crossover lobing issues if you are not careful...

Hi Pinkmouse,

The baffle angle from vertical is 16 degrees, so yes it is steep but that was the amount required to bring the drivers into time align.

Off-axis response on the Scan is average from my open baffle tests so far, though you wouldn't think it looking at the plots.

Hmm, what if I were to bring the top section of the sloping baffle back in to vertical just for the tweeter?

[pinkmouse]

You might be ok, build a test baffle first, and then do some measuring. I just don't want you to spend all that time and effort to get something that doesn't perform to the standard you should get from the quality components you bought .

[PHilgeman]

With RE to the bass alignment.

I have a HIGHLY absorbtive/diffusive, very large listening room, and about two months ago I finished a sealed box speaker with a Q of .7 and an F3 of about 51 Hz, I did this to properly match to my room. It indeed does match to my room and provides flat bass response well into the upper 20's. However, in a smaller, 'stiffer' room, this spekaer would probably be overpowering in the 50-100Hz range. I would be very careful about the speaker-room match, as proper leveling in this reigon can make or break a full-range speaker geared towards accurate response.

I would start by making a sealed box with a single L22 in it, and just measuring it nearfield and then placing it in several aproximate speaker locations for a reality check. Nearfield it should roll-off early and if your room is small and stiff, it will probably provide good flat bass down to the 30's or so would be my guess, but maybe with a broad-ish dip if it really starts to roll-off early nearfield.

-Paul