Budget woofer system with Horn

[more10]

The Behringers are marginally better than the Ranes. But you can use them to find a filter curve for the horns. The horns are quite nonliear.

The vented boxes will output some midrange through the ports. Limiting this midrange (throuch damping material) will improve sound. Or you could rebuild the boxes with a 8-12 inch midrange in a dogbox replacing one 15 incher, creating a 3-way system.

[gwho]

fyi, I did not see any diaphragms on ebay from great plains for the 288-8k. I only saw ones from hong kong.

gwho

[more10]

Do you have measuring equipment? If not, a cheap solution is UMIK-1 from miniDSP. You will also need a PC and measuring software. REW, Holmimpulse or Arta, or all of them. These are all free/shareware, so they are not very intuitive.

You really need to start measuring now.

[more10]

fyi, I did not see any diaphragms on ebay from great plains for the 288-8k. I only saw ones from hong kong.

gwho

http://www.ebay.com/itm/Altec-Lansin...item35d03d7b87

Ok, I will read the manual for you and do the googling :-)

[gwho]

Thanks for the help more10. Will I have to EQ the horn since it is non-linear? Would the passive crossover that I have (1285-8b) have compensation for the horn?

regards,
gwho

[gwho]

The only thing I have is a radio shack meter. I have been using a receiver that has built in eq for low frequency using a microphone to the processor. I probably should try to get some of the measurement software.

gwho

[more10]

Thanks for the help more10. Will I have to EQ the horn since it is non-linear? Would the passive crossover that I have (1285-8b) have compensation for the horn?

regards,
gwho

You are welcome.

You will need to EQ the the horns since the horn/driver combination is non-linear. The horn is a kind of CD (Constant Directivity) horn. The frequency curve is falling (with frequency). CD-horn at wikipedia.

The spec for the crossover doesn't mention EQ, but it does mention your horn.

[gwho]

Thanks more10. This is all information that I do not know. I will try to read up on it. At least right now I would like to keep it as a two-way with a sub. I don't want to over complicate it. I will set the crossover at 500hz and add eq. to compensate for the non-linearity of the horn. I will also fill the box with some fiber fill, recap the crossover, and pick up a diaphragm for the dead driver. If it sounds significantly better than the horn that works I will also buy a diaphragm for that speaker.

gwho

[more10]

In case you want to go 3-way (excuding sub) I have found the Altec audio-nirvana midrange driver for you:

http://www.ebay.com/itm/MATCHED-PAIR...item27de4b13a6

/M

[gwho]

Have you tried this three way? I assume the smaller speaker goes up to a higher frequency. I thought the purpose of the two way was to eliminate a crossover over in the critical band for music. Doe the smaller speaker integrate better with the horn.

Thanks
gwho

[more10]

No I havn't tried any Altec drivers. I am a JBL-guy :-). First you try to put some damping material into the box. If you have problems with midrange output through the vents, you can try a threeway.

A threeway has a few advantages over a twoway:
1) No midrange through the ports
2) Smaller diameter cone will not beam as much as a large diameter cone and also it doesn't have breakup modes in midrange.

[gwho]

Thank more10! You had mentioned that the horn needs equalization. Could you name some reasonably priced equalizers that sound good. You had mentioned dbx, is this there analog equipment or digital devices. I've ordered the diaphragm from great plains. I will put stuffing in the 8256. Has anyone found any issues with the stock wire Altec used in the box? It is not the thickest wire. Also, I can't seem to find a schematic of the 1285-8B crossover. I'd like to change out the components (inductor and capacitors) related to only the 500Hz portion of the crossover to see how it sounds. The cap value is easy but I would like to know the inductor value (I don't have an lcr meter).

Regards,
gwho

[more10]

For testing you could go with a dbx 2231 or similar. I believe you will need about 18 dB span. Another interesting option is the miniDSP HD (digital crossover). There are also some analog active filters with CD compensation, but its a gamble to use them with your horn.

You don't have to replace the inductors in you filter. Unless you think they are made of too thin wire.

[gwho]

I pulled the driver off of the horn to see what the problem might be. The dome looks good but it appears that the wire from the diaphragm is broken. I took a couple pictures. Is this something that can be fixed or is it fatal?

Thanks
gwho

[Eaulive]

It can be fixed of course, but you have to have a good iron and a steady hand.... and work fast!