Dayton DA175-8 and Seas 27 TBC/G

[golo]

Sorry about my english.

Hi. This is the first time I write in this greate forum and the first time that I do a home audio. I always made car audio projects.

I have read some posts in this forum and the zaphaudio page. I am from Brazil so it is a little hard for me to understand english.

My project is a MTM.
I want to use the Seas 27 TVC/G and the dayton DA 175-8 mid ou Dayton RS180S-8.

The crossover point I don´t know were to cross. I was thinking 2500 Hz, but is this too high?
I wont use a L-pad to low the tweeter, I will use the gain in the amplifier.

What box shoud I use for the mid? LT, TQWT, Horn or bass reflex?


P.S I have searched, but i did not found where to cross.

Thank you.

[rjb]

Although PE say "frequency range 35Hz to 10Khz" if you look at the frequency curve they supply there is a big dip starting at about 1.5k, and cone breakup peak at 5.5K and above.
I think you would need to cross below 2K, which probably won't suit your tweeter. (Very rough rule of thumb-cross over below one third of first breakup frequency).
Designs I have seen usually incorporate a mid range as well, ( as I am doing). or use a 3 inch "full range". See MarkMck early post, (thread 30737) or his website for examples. (His cross-over is about 350 Hz from memory.
Perhaps an Aura NS3 ot HiVi BS3?

[rjb]

BTW, PE have both sealed and reflex designs on their web site. I have also modeled good results with ML-TL and tapered TL for the DA175, using MJK's mathcad work sheets. It depends on your preferences, and the size you want to make the box which is best.

[golo]

Thank you for your reply.

If I use the Dayton RS180S-8, will I can I cross it at 2500 Hz or higher?
If i use a Zobel if the dayton DA 175-8, will it correct the dip around 1.5kh?
Which is the lesser I can cross this tweeter?

[rjb]

Sorry- I cannot answer your questions as I have not used either the RS180 or your tweeter. I suggest you look for other peoples designs using only one of these drivers. See where they choose to crossover, and then see if the two can be made to match. You will probably find helpful comments as well.
Personally I am not in favour of compensation networks of more than one or two db in a driver circuit, and the dip in the DA175 seems more than I would want to try to correct.

[hongrn]

I'm doing the same design with the RS180 and the Seas H1212 in a MTM configuration, but adding a RSHF 10" sub and 12" DVC passive radiator to the tower. The H1212, according to people who have used it before, can be crossed at 1,800Hz. Mine will also be a 4th order LR at 1,800.

Hong

[golo]

Thank you for replying.

I am going to use seas H1212. 4 order crossover is too much. The price of a cross like this it too high.
I will have to use this mid bass: Dayton Da135
or this
Silver Flute
Because they are light. It is very expensive to bring products from U.S. to Brazil.
Silverflute data

I´m thinking on crossing the tweeter at 2500 hz 2 order.

[golo]

I have decided that i am goig to use a midbass that you already know.
I will use The vifa P17http://www.partsexpress.com/pe/showd..._ID=7856&DID=7.

The will be 2 vifa and 1 tweeter.
I am going to use it in a LT ou TQWT.

Now I have some questions:
A - Should i worry with Diffraction Loss in a Lt or tqwt?
B - Why use a 4r order crossover instead a 2 order? 4 order have a lot of phase problem don´t it?
C - If I use a 2 order should i use a notch filter? Does this take some quality of the sound?

[golo]

Help me