need some help picking some 3-ways

[adolphe]

I just realized, basically what I'm asking in my last post about driver configuration is, what would the difference be between the Veritas and the dayton 8 (if the vertias used 8's instead of 10's)?

[RobHance]

I would suggest taking a look at Dennis Murphy's Vifa Tower. It uses Vifa's 8" P21 woofer in a ported enclosure. I have not heard it myself but Dennis is a proven crossover wiz with an impressive amount of well-known designs (such as MBOW1 and Ellis Audio's 1801). Since it is a two-way design spending the extra money on Vifa drivers will still keep you in your budget.

[MtBiker]

Dennis Murphy's Vifa tower is a good choice if you want to do something simple and get guaranteed results. The P21 is a bit dated, although those Dayton 8" drivers are nothing special either. Now the new reference series Dayton 8" may be another story, but you will need a ridiculously steep crossover to use that in a 2 way.

If I were you would go with a high quality 5" or 6" mid in a 2 way and add a sub later. If you can still hear to 20kHz then you are probably young enough that you are going to eventually insist on realistic extension to 20Hz as well, in which case an 8" driver is going to be just as worthless as a smaller one.

[adolphe]

well I actually already have a sub, it's an 8" Energy that I use with my surround system. I was just thinking that it would be nice from a simplistic standpoint to not run one. if I find that the speakers that I build don't have enough low end, I can always just switch it on.

I think I still like the Dayton 8 project the best at this point, but I might just look into alternative drivers and way's of extending the lower frequency response more.

[morbo]

There are lots of kits available, the ones you've already mentioned are great, also check out:

www.creativesoundsolutions.ca
www.rawacoustics.ca

and the free designs at

www.murphyblaster.com
www.zaphaudio.com


and being that you're an engineer, for the real heavy duty stuff (for me at least), this site has a huge amount of info written in a very engineering oriented style:

http://www.linkwitzlab.com/

[tamosius]

adolphe,

Have you considered Eton 11.2 kit available from Madisound?
I'm in the process of picking some kit.. I was thinking about Thor TL vs. Eton 11.2.
They are quite different speakers... I expect Eton to have better bass, while Thor seems (from other people oppinions) very clean sounding speakers...

why does it have to be so difficult to decide?!

[Jay]

Originally posted by adolphe

One question that I've come up with is, what's a good relative db level in the low frequencies (sub-70Hz or so) when not using a sub? What I mean is, when you look at a SPL vs Freq graph from 20Hz-20kHz, and the SPL begins to trail off below 70Hz (for example, and where above 70Hz is flat at some db level), at what delta-db will you start to say "this needs a sub-woofer"? Or does that have a completely subjective answer?

You can design your box to get the type of roll-off you want. Basically you can create a slight 'bump' at roll-off if you want to boost the bass. Generally, the quality is better when the roll-off is smooth (or has a shallow, gradual roll-off) like that of TL design, but which one is better depends on taste and the capability of the woofer (with a little help from the box) to produce lows.

With small bookshelf without intention to use a sub, and with woofer having Fs around 60 Hz, it is IMO okay to boost the bass that way. But I don't know, when I look at designs out there, it seems the ones that are tuned to a too low frequency never have a better reputation.

The decision of using a sub or not, or the decision how to tune the box, or even to choose a woofer, is IMO should take into account the location of important instrument in the frequency band. IMO, there's a narrow band of frequency around 40-60Hz where lies important instrument sounds. I think the woofer need to have at least Fs=45 (and tuned to about 60 Hz) so that the subwoofer can be 'avoided' (or okay without it).

P13 has Fs=60. I have more than often heard dissapointment with the bass. The midrange is good, but this is IMO the critical situation where bass is more important than just sweet midrange.

[rcw]

Most popular rock and r&b recordings and live performances were based upon a 60Hz. punch peak with a roll off thereafter, and most mass market "popular", "hi fi" speakers are built to reproduce this. This allowed enough playing time to be fitted on vinyl records and allowed easily transported and affordable p.a. systems on the road, whilst giving sufficient physical sensation in the form of chest resonances.
Since the advent of cd and digital recording popular music has much more low bass content, and mobile p.a. systems that go down to 30 and even 20Hz. are quite common. I would say that for any music that has appreciable content below 60Hz, small speakers with 6-8inch woofers are inadequate and a subwoofer is indicated.