Tannoy/Dayton 3 way...comments/suggestions?

[mpmarino]

Hi folks,

I intend to build a loudspeaker system for 2 channel and occasional movie watching. It needs to be musical and very dynamic...gee, thats a surprise huh I think I can do it, I'll be throwing a lot of hardware at it. I need guidance as to which way to throw said hardware. I've intended to start on this many times for the past year but amplifier projects kept working thier way to the top

I plan on using a Tannoy K3148 coincidental for the top and a Dayton Titanic 12 for the bottom. The speaker will be a single dual chamber 'chassis' with the sub built in. It will be completely active 24dB LR, with an Adcom 555MKII for the daytons. The amps for the tops will be whatever I have built at the time that I feel like hearing

Top chamber:

1 ft3 for the Tannoy K3148. This driver models terribly in 1ft3 as you can see in the red line on the pic. Now, I would like to try an aperiodic vent to lower the Q. I am thinking that since I really am not interested in bass extension I could lower it plenty and smooth it right over. Tannoy spl:woofer-~93dB / tweeter- ~103dB


Bottom chamber:

2 ft3 for the Dayton 12 MKIII. Front facing. I am in the usual quandary here. I am strongly leaning towards vented as I would like to keep the sensitivity of the 'sub' up closer to that of the Tannoy. I know I'll be giving it plenty of power but I'd like to use as little of it as I can. The green slope is that of the Dayton in a 2 ft3 box tuned to 23hz. Dayton SPL 88.6 dB 2.83V/1m.

Please guys, I could use constructive criticism.

Do you think this will work?
Do you see a fatal error?
What am I forgetting about?
Should the vent should face front or rear?

Thanks guys.......

edit: the Tannoy has a 12" woofer

[sreten]

Hi,

what red line ? with a 24dB/oct c/o Q probably doesn't matter.


/sreten.

[mpmarino]

Thanks for looking Sreten,

Yuo don't see a red curve in the graph which represents the Tannoy? ..or are you saying with 24dB it's irrelevant?

Any comments truly appreciated.

I will probably get only one chance at the build....

[sreten]

Hi,

sorry, I can see the faint red line.

Depending on your c/o frequency, if you want the tannoy roll
-off to be true 4th order L/R acoustic then you can build an
active crossover that electrically sums with the box alignment
to give the required acoustic response. That is a somewhat
overdamped 2nd order active filter + underdamped box 2nd
order roll-off = 24dB/oct 4th order L/R acoustic high pass.

edit : also with 2cuft for the Titanic III sealed box Q is 0.67
which is far too high for good quality reflexed bass, IMO you
should use the III sealed and let room gain bump up low bass.

/sreten.

[mpmarino]

Thanks,
sorry for all the questions. The last speak I built was 18 years ago

I understand what you mean for the Tannoy.
>Maybe planet 10 can comment on the aperiodic idea ???



For the Dayton you stated that in 2 ft3 sealed the Q of .67 is too high. Isn't the goal .707 which would be somewhere around 1.5 ft3 if I were to go sealed? Are you suggesting go somewhere around .5 Q for power handling reasons etc? This wouldn't be somewhat boomy?

I'm not arguing...just probing

Hey thanks...

[sreten]

Hi,

Sealed box Q of 0.67 is too high to reflex for good bass.

Target for a sealed box is generally Q = 0.6 to 0.8 depending on taste.

Q=0.5 is completely damped and would give very tight bass and
a very room friendly bass roll-off, but can need a much larger box
than say Q = 0.6 depending on the driver.
The lower the sealed Q the less boomy it is.

My target for your speakers would be sealed Q = ~ 0.65.

The aperiodic loading of the Tannoy is pointless due to the c/o.

Regards,

/sreten.

[mpmarino]

Thanks very much for the advice. I'm much closer now

[tinitus]

http://www.partsexpress.com/pe/pshow...46&rak=295-190

nah, maybe not

[mpmarino]

I wonder if it would be Sacrelidge if I tore apart a perfectly good set of Infinity RS4B (1980's) and used the shell for this project. They sound unimpressive to me and I think the parts are worth more than the sum. I love the appearance and would spend way too much time duplicating it. Is it a coincidence that internal volume is perfect...or is it destiny?