Help needed: newbie.

[LukeF]

Hi there,

I am in the process of trying to put together a pair of diy loudspeakers, these will be my 2nd pair ive done, although the first pair weren't that flash, using just basic drivers and a pre-made crossover.

Anyway to the subject, I've been wanting to make a 3-way loudspeaer using a Vifa XT25TG tweeter, Vifa D75MX mid and Peerless HDS 830884 woofer. I Choose these drivers because they are fairly easily found in my area and also because their spl seems to be similar with figures of 91.1 , 92 and 89.3 respectivly. By simply looking at the FR graphs i thought crossover points of around 700hz and 2khz would be roughly on the right track.

Now the question. Am i on the right track, my limited knowledge can only get me so far. I have know idea on how to design or make a crossover, (althought i am keen to do so). Ive been reading these forums for awhile now but am getting frustrated with the slow progress of my understanding on the matter.

Any help suggestions would be much appreciated. And yes box design as well

Cheers!

 

[sreten]

Hi,

You are not particualarly on the right track. A 91dB bass unit (due to
BSC) pans out at a midrange / overall sensitivity of 85 to 87 dB.

The Vifa 3" dome is old as the hills and has a poor reputation.

You could do a lot worse than building this :
http://www.rjbaudio.com/AlpheusMkII/alpheusmkii.html

If you prefer sensitivity over bass extension a 2.5 way is appropriate.

See : http://www.diyaudio.com/forums/showthread.php?s=&threadid=113361

/sreten.


http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/

http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/
http://www.rjbaudio.com/projects.html
http://www.zaphaudio.com/

 

[Shaun]

Hi LukeF

Where does one start? Perhaps you could try this link TrueAudio and read some more of other builders' projects Speakerbuilding.com and Elliot Sound Products (look here first). You could search for designs that use your drivers and try and learn from those projects what decisions the designers had made regarding the useability of the respective drivers.

You could also go over to Speakerworshop.com Speakerworshop.com and read through the speaker design tutorial there. I recommend SpeakerWorkshop (it's free!). You could buy or build a measurement microphone to use with your computer's sound card. This would enable you to do acoustic measurements and model a crossover to suit your project in the SpeakerWorkshop environment.

Sorry this info is so fragmented. Please feel free to ask specific questions.

 

[grantnsw]

Hi Luke,
Please read this thread:
http://www.diyaudio.com/forums/showthread.php?threadid=88567
Sreten helped me a great deal, he really knows his stuff , the only reason I haven't proceeded with 'my' design is lack of funds/time etc. Yes the D75 is 20 years old and awful, don't bother with it. 3-way speakers are very complex to design, as Sreten implies try a published design. grant

 

[Shaun]

Aha! Sreten posted while I was still writing..

Here is a project that uses the Vifa mid The Vifa X3 . However, if you can get hold of the Dayton RS52 mid, then go for it. It is very good. A poor performing driver can really ruin a project!