2225H in inproperly tuned cabinet?

[Steve Racey]

While I have all the technical specs on this driver, in its current cabinet, the driver sounds flat with very little bass. The cabinet is properly sealed, with no rattles even driven loud.

This custom made cabinet Vb is 4.301 cu ft. V(total) 4.541 cu.ft. Two 4 inch diameter ports measured from the rear of port which is flush to the baffle 5.25 inches. The Fs of the 2225H is 40Hz.

Any suggestions??

Thanks,

Steve

[Zilch]

Your 39.7 Hz tuning (black) has a bit better bass (useable to ~34 Hz) than BB6P's suggested extended bass tuning (red).

I'm afraid that's it for 2225H unless you want to get radical with a bandpass or active assisted alignment.

You can get a couple of Hz lower by extending the ports to 8", but you lose power handling capacity at the low end.

Put it against the wall or in a corner for some boundary reinforcement.... :dont-know

[4313B]

While I have all the technical specs on this driver, in its current cabinet, the driver sounds flat with very little bass. The cabinet is properly sealed, with no rattles even driven loud.

This custom made cabinet Vb is 4.301 cu ft. V(total) 4.541 cu.ft. Two 4 inch diameter ports measured from the rear of port which is flush to the baffle 5.25 inches. The Fs of the 2225H is 40Hz.

Any suggestions??How did you measure the tuning frequency of the box?

[Steve Racey]

Thanks for the reply. At least I know the original box was tuned to the driver. As these are vintage speakers I am going to keep them for home theatre use in a new custom cabinets rather than DJ use. I have purchased cheaper non JBL speakers that have an Fs of 35 Hz in the same box. Do the port tubes need to be re- adjusted?

A friend of mine made some calculations from bass box pro.

Their is a wealth of very talented people on this forum and your help to
newcomers like myself is much appreciated!!!

[Zilch]

Fs is a driver characteristic, not a box parameter.

Ask your friend to run that other driver in Bass Box for you. That'll tell whether it will work well in the same sized box, and revised port dimensions for optimum performance.

2225H doesn't do extended bass well, but what it does deliver is "punch." Some users like that better.... :thmbsup:

[4313B]

Do the port tubes need to be re- adjusted?You need to establish the actual tuning frequency of your box.

[Zilch]

You need to establish the actual tuning frequency of your box.Do you know how to do that, Steve, and do you have the means?

The numbers I'm stating are theoretical, based upon the dimensions you provided. They reveal nothing about how your box is actually performing....

[4313B]

They reveal nothing about how your box is actually performing....Now we're talking.

One needs to baseline what they have. Once they do that they will know what their real effective volume and tuning are and can use the software packages to extrapolate from there.

In this instance I would suspect that the net effective volume is larger than expected and the tuning frequency is lower than desired, but I could be wrong. It could also be the typical balance issue between midband efficiency and low end response or due to room acoustics. It could be a combination of all these factors. I'm quite familiar with the 2225H (imagine that) and it's really only "missing" the bottom octave and some change.

[jbl]

I can supply the 'real world' listening experience rather than how the driver responds in different boxes since I've been using the 2225H in a 4507 cabinet for over 20 years.
If you have the right box tuning and box size, the 2225H produces a great bass as well as 'slam'. Try to base your cabinet on the 4507. This is what JBL used in their 4647/4671 system. That's a 5 ft3 cabinet tuned to 40 Hz.
I have that system and can say that the bass is fine. If you're looking for a sub, that it won't do. You'll get good bass to around 32 Hz along with a very realistic sounding mid. The slam on drums is unreal!
Hope this helps.

Ron

[4313B]

Yep.

And once again here is the link for those who want tried and true:

JBL Professional Enclosure Guide (http://www.jblpro.com/pub/manuals/enclgde.pdf)

[Steve Racey]

Thanks for all the help, again. The JBL Enclosure is exactly what I am looking for!!!

Steve