How does a back-loaded horn enclosure affect frequency response?

[fairy25]

Below is a rough comparison of a driver in a reflex vs a larger BLH - I hope it isn't completely confusing.

Thank you a lot, Fred. The picture you provided has very useful information. Now I can see that:

1. The BLH enclosure amplifies different bands of frequencies,not just a single peak like the simple bass reflex one. From my understanding of your picture, the BLH is less flat compared to the simple bass-reflex. Is that true?

2. The longer the horn is, the lower the bass gets.

3. There's no way for an enclosure to beat the response of the driver in free-air, is there?

All of you guys are great and very helpful!

 

[Scottmoose]

Thank you a lot, Fred. The picture you provided has very useful information. Now I can see that:

1. The BLH enclosure amplifies different bands of frequencies,not just a single peak like the simple bass reflex one.

To a point, although it depends how you define (and tune) a vented box; a chambered back-horn is in essence an [the most] extreme version of the vented box, so it's a matter of degree.

From my understanding of your picture, the BLH is less flat compared to the simple bass-reflex. Is that true?

No. It can be true. It depends on the specifics of the design and how heavily compromised the expansion etc. is.

2. The longer the horn is, the lower the bass gets.

In a sense, yes. The longer the horn, the lower its quarter-wave tuning frequency is. Whether it will produce any reasonable gain (aka 'output') though is another matter: again, that depends on how heavily compromised the expansion is relative to the ideal. You could, for instance, bolt a 20ft long horn to the back of a Fostex FE206NV, but if that horn only has a throat CSA of 1in^2 and a terminus area of 6in^2, it's not going to give you a great deal of useful output.

3. There's no way for an enclosure to beat the response of the driver in free-air, is there?

That rather depends what you mean by 'beat the response' (?).