Building Two Way Bookshelf (AVI EL-130 Vifa XT25TG30-04)

[sutantoroy]

Hello Guys.

I am thinking to build a two way bookshelf speaker using AVI EL-130 midbass driver and Vifa XT-25-TG30 tweeter.

I dont know how to design speakers. So i hope that i can learn step by step here.

AFAIK the steps to build speaker:
1. Chosing driver
2. Designing box
3. Designing XO
4. Building box
5. Testing and fixing the XO design
6. Finishing

I choose those two driver because those two have adequate frequency range to complement each other.

Next step is to calculate the speaker box. Here i am confused. AFAIK calculating the box volume is based only on the midbass driver parameter right? Is tweeter also have influence to the box volume? Should there any special chamber for the tweeter inside the box?

Thanks before.

[PeteMcK]

re: 'those two have adequate frequency range to complement each other' there is no freq response graph for the mid-bass driver on the link so that is unknown
re:'calculating the box volume is based only on the midbass driver parameter right?' - yes
re:'Is tweeter also have influence to the box volume? Should there any special chamber for the tweeter inside the box?' - no & no.

[sutantoroy]

Thanks for the response Pete, i am assuming that the frequency response from the default XO cutting point should be ok (i have the original passive XO from the set speaker of this EL-130, it cutted -18dB at 3kHz).

Now about the box. Every box speaker calculator i see always need Fs parameter, which i dont find in this EL-130 data spec's. It's only write Fo, how can i know the Fs value?

About the enclosure type which one is better, sealed or vented? I prefer the tone quality (tight bass) over more bass quantity. Big physic wont be a problem, but prefer the compact if can .

[PeteMcK]

Fo appears to be Fs
If you have the original xover for this driver, I'd use the LP section, but the HP section for the tweeter will need to be designed from scratch
The box – to get any bass out of this driver you’ll need a ported EBS design
This is where the box is tuned below the Fs; it gives bass lower down than a normal QB3 alignment, but that bass will be a couple of dB below the mids in level.
(You can raise the level with your bass tone control)
Approx 4.5L tuned to 47Hz looks about right.

Sealed would require much more Eq. ‘tight bass’ doesn’t depend on whether the box is sealed or vented, but for a ported box, on how well it is damped.

[sutantoroy]

Pete,

just curious, will a sealed enclosure isobaric configuration midbass produce good and deep bass with adequate SPL? (Let say, down to 40Hz with quite flat respon on low frequency, tolerance about one dB beyond the upper frequencies)

I read that a vented box will more sensitive on speaker placement, affecting the bass response (especially the back ported one), is it true? Its also say that building a good vented speaker is much harder than the sealed one, how is your experiences?

[PeteMcK]

Isobaric doesn't add any advantage except for smaller box size, which you don't need with your drivers

Re:'building a good vented speaker is much harder than the sealed one' no, it's only a matter of getting port tuning and internal damping right

re:'a vented box will more sensitive on speaker placement' - not at all for bass frequencies