On the fence

[mikey15]

Hey guys Im debating on what to build. I want to use the Seas Reed cone mids and the Seas 27TBFCG tweet. I want a MTMWW The dilema is do I go with 8's or 10's. I am planning a Guys Room and it will have a false wall. The problem is I can only go about 2.5' out. If I use 10's will that put the back of the speker too close to the back wall. Oh yeah I plan to put the front speakrs behind the wall with a perfed screen. Also I want to match the center as close as possible. I am leaning towards the Emotiva XPA-5 so I will have around 200 watts a channel. Eventually I will also get the XPA-2 so it will go up to 250 watts for the L/R. Thanks for your input
Mike

[Hdale85]

Are you going to use a sub?

[ThomasW]

The 5" or 7" Seas Reed Paper driver?

Given this is a completely new speaker, we assume you're knowledgeable regarding loudspeaker measurement/testing, and know how to properly design a crossover?

[mikey15]

yes on the sub(an llt) no on the crossover. Half of the fun for me is learning. I'm currently reading the loudspeaker cook book. I know I'm in for a lot of trial and error

[ThomasW]

Best to start out having measurements taken with the drivers mounted in the baffle you intend to use...

[Jed]

Hey guys Im debating on what to build. I want to use the Seas Reed cone mids and the Seas 27TBFCG tweet. I want a MTMWW The dilema is do I go with 8's or 10's. I am planning a Guys Room and it will have a false wall. The problem is I can only go about 2.5' out. If I use 10's will that put the back of the speker too close to the back wall. Oh yeah I plan to put the front speakrs behind the wall with a perfed screen. Also I want to match the center as close as possible. I am leaning towards the Emotiva XPA-5 so I will have around 200 watts a channel. Eventually I will also get the XPA-2 so it will go up to 250 watts for the L/R. Thanks for your input
Mike

Hey Mike,

Welcome to the forum. :T The Seas Reed cone drivers are very nice. Since you've never designed a speaker, I'd recommend going with a 2 way for your first design. That said, IMO, you should build a proven design first to get some experience first. I'd take a look at zaphaudio.com for some ideas or check out my website to see what is involved with building a speaker from start to scratch. Then, when you have some more specific questions let us know so we can guide you in the build process.

[Dave Bullet]

Hi Mike,

As Jed said, you've picked some good drivers, but simply using textbook crossover formulas will be a hit and miss result. The two main reasons for that is:
1. Textbook formulas assume a constant resistance from all drivers across all frequencies. This is never the case (look at the varying impedance curves of the drivers you are looking at)

2. Textbook formulas do not take into account your baffle dimensions, which affect ripple (the peaks and troughs) and baffle step (the upto 6dB rise when frequencies increase such as the baffle becomes effective at reflecting the wavefront).

The Loudspeaker design cookbook in my opinion grossly overlooks the above two points and implies you can design a really good crossover just by using formulas.

If you really want to use that driver combination, try to use an existing design. Jay Kim has designed a ER18 / 27TDFC combination, which you could probably replace the 27TDFC with a 27TBFC/G if you pad down 1dB more. Here is his design:

http://www.geocities.com/woove99/Spkrbldg/ER18RNX_MTM_2Way.htm

Otherwise, I'd strongly recommend you build an existing design meeting the same goals (sounds like good dynamics / higher SPL is your aim). Many of the Dayton RS based designs posted here (Missions accomplished) will meet that (and more). You will still learn alot - even if it is building an existing design. You can then invest in a measurement setup (which doesn't have to be much) and do your own designs down the track.

Cheers,
David.

[peter_m]

Mikey15,
what you are planning to embark on is a really rough and bumpy road that goes uphill most of the way. If that doesn;t scare you, look in to these drivers:

Peerless 830882 (mids)
Seas 22TAFG (highs)

They both offer better off-axis dispersion and in the case of the Peerless, it has lower distortion then the Seas ER-15. If you are keeping in the larger 7" mids, look into the Vifa XG18, even lower distortion then the Peerless and the Seas.

Good luck,
Peter

[mikey15]

I think we have established I'm embarking on a very rough road but I'm up for it. I'm one of those that says "hey I can do that" and wind up teaching mysef through trial and error. I've done lots of construction so I'm not worried about building the cabinets. I've run all the electrical in our old basement build"lots of trial and error there but it passed inspection. I can solder from my r/c car days. I even have a Hako soldering station. I just need to learn this crossover stuff. When you say mount the speakers in the baffle then take measurements. Do you mean model the enclosure an build it then take measurements. Or just build the baffle and do initial measurements. Sorry if that sounds like a dumb question
thanks
Mike

[Jed]

http://www.claudionegro.com/

This website will help you get started with measurements.

As well as www.rjbaudio.com

Jed