RS150 Sealed Unibox

[parodielin]

I read an old post saying RS150 sealed in a .25 PE box can generate a F3 at 80, Q=0.7.

I tried in the Unibox with minimal fill and minimal leakage. The best I can come up with is F3 = 87 Q=0.673. I used the new RS150 T/S parameters from PE.

Did I do anything wrong?

[cjd]

New (unshielded) drivers have different T/S parameters.

That said, I prefer a shade under .7 personally, and think these results look superb. Especially because Unibox doesn't remove box volume for driver assembly or crossover.

[parodielin]

New (unshielded) drivers have different T/S parameters.

That said, I prefer a shade under .7 personally, and think these results look superb. Especially because Unibox doesn't remove box volume for driver assembly or crossover.

So would this mean a no-no to put RS150 in a sealed .25 if I want to cross with the sub at 60-80Hz? (Assuming I didn't do anything wrong)

How big is the difference between F3=87 vs F3=80? If I change the parameter to heavily fill, the result will be F3=93.

[cjd]

Ahh, right. I see, F3 is what you noticed, and I noticed the Q.

It'll be fine. Q below .707 and an F3 that close to your target, you'll have MUCH worse issues from room nodes and the like, than a tiny ~1dB dip since F3 isn't exactly at 80Hz.

[parodielin]

Ahh, right. I see, F3 is what you noticed, and I noticed the Q.

It'll be fine. Q below .707 and an F3 that close to your target, you'll have MUCH worse issues from room nodes and the like, than a tiny ~1dB dip since F3 isn't exactly at 80Hz.

cjd - your approval means a lot to me... Great to know you think the new Q is better. I plugged the shielded version - the Q is higher and F3 is like 85 so not that much difference.

If I might add a few newbie thoughts, Unibox tells me the F3 at 87Hz, means at 87Hz, the SPL will be 3 db down from 87db, which is 84db at 87Hz.

But in the final system, the F3 might be different. For example, if the crossover uses full BSC and the final sensitivity is 83 db, the F3, which is 80db could be lower than 87Hz. (Like 75Hz)

So Unibox says RS150 in a .25 sealed box has an overall 87db, with 84 db at 87Hz. The final system could have a system sensitivity at 83db, with 80 db at 75Hz.

Am I off-base? ;x(

[cjd]

F3 is the -3dB point.

So if you lower overall sensitivity (take baffle step into account) or just turn the volume down, it's still -3dB at this point - but the actual dB level is different...

I think this is what you are saying.

[Ray_D]

Baffle step is the magic word(s)

What Chris said about baffle step may have slipped by; but, if you are worried about sensitivity you need to consider it.

People almost never consider baffle step when they use these simulations and expect to get certain sensitivities. You are going to lose 6 dB if you design the crossover for full compensation.

Check this out.

http://www.tolvan.com/edge/

Ray