Questions

[service_guy]

Hi All.
I found my way here from the Home Theater Shack DIY Subwoofer forum and CSS.

I am looking into full range speakers as an option for me to build.
What I like about the concept is, no crossover to fuss with and tweak, driver placement issues on the baffle, and all the other bother with a 2 way or three way system.
I am no stranger to building speakers (did a house brand back when I worked at an audio store) so box construction and driver fitting is a no brainer for me.

My question is:
What kind of output levels can be expected with these drivers (Alpair 7, ALPAIR10FR and ALPAIR12)?

My listening room is 15x19x8 (carpet on the floor) partly open to the rest of the house.

My current system is:
Linn LP12
Cambridge Audio CD 6
B&K Pro 10 MC
Harman/Kardon Citation 16 (Solid State 150 watts rms in to 8 ohm's)
Paradigm Studio 60's V3 Rosenut Finish (bought at dealer cost, good deal)
Tara Labs Space and Time Power cable (Pre-amp)
Tara Labs Reference Gen 2 bi-wire Speaker Cable
Vampire Cable Power Cord (CD Player)
Vampire Cable Silver Interconnects CD-Pre Amp-Power Amp.

Low bass and subwoofer duty is well looked after (see my threads at the Shack)
I am only in need of 100 hz and up, so either and active crossover or good passive to the Mark Audio's.

I know the H/K is to much power, but has good current and is a good sounding amp for it's age (34 years old) but I don't want to kill the little full range'ers trying to get good listening levels (I know that is subjective, but levels that makes carrying on a normal conversation difficult) in a room the size I have.

So if anyone can help me out, I will pick drivers and be on my way.
Thanks in advance.
Dave.

[service_guy]

Nobody have answer's to my questions?
Lots of views, but no takers.
Dave.

[planet10]

Hi Dave,

If you want loud you want the bigger driver. A12 is rated as 89 dB/1m. And demand in the bass will be minimal, so you likely have no need to worry about running into xMax.

C16 outputs 150 w (but doesn't overload all that gracefully from my recollection), lets say 160W (makes the math easier). Say you want to reserve 10 dB headroom, then you have average 16 W. Lets guess that in your smallish room level at 2 m is about what you get as "ambient" thruout the room, then you have 99 dB average levels. No sane person is going to listen at those levels. Give yourself 20 dB headroom and at 89 dB it would still be REAL loud.

In my much bigger room i'd be perfectly happy with a good 10 w tube amp with good overload recovery,

You can do the math for the other drivers.

At 100 Hz or so you want to put the XO before the amplifier.

dave

[markaudio]

Hi Dave (Service Guy),
Following on from Dave's (Planet 10) comments, I'd suggest the Alpair 12 to take care of lower mids and up. The output from this driver will be more than enough for your set up.

Just one thought regarding your Citation 16. It's knocking on in years:

harman/kardon ƒXƒeƒŒƒIƒpƒ��[ƒAƒ“ƒvCitation16‚ÌŽd—l ƒn�[ƒ}ƒ“ƒJ�[ƒhƒ“

Have you done any work to it? I'd be tempted to check it over. The transformers are likely to be bomb proof but other components maybe a different matter. I'm a devotee of older solid state (Sansui 900 series & Sony Taf-333EX all Japan units) but nothing lasts forever. Both my beloved amps are in dry dock undergoing maintenance. Tony's stepped in and lent me a very nice 300B.

The cones on the Alp12's are quite micro-resonance sensitive so a clean signal feed is desirable.

Cheers

Mark.

[service_guy]

Hi Mark.
Thanks for the response.
No I have not done anything to the H/K and yes it is getting on in years.
I am in the process of getting my Golden Tube Audio SE-85 corrected so that it will not send the EL-34's off like flash bulbs when trying to listen to it (long story).
If it can be corrected to work properly I will use that amp, if not I am going to look at another tube amp.
The H/K will be retired if I can find a tube amp that suits my needs and does not cost a mint.

I'd suggest the Alpair 12 to take care of lower mids and up. The output from this driver will be more than enough for your set up.

That is what I was looking for.
When the time comes I will be purchasing from CSS.
Mark, am I better to use an electronic crossover or a high quality cap to high pass the Alpair 12?
I used to do that in car audio if the customer did not want to spend money on an x-over, I would cap the positive lead for high pass.

Thanks Again.
Dave.

[markaudio]

Hi Dave (Service guy),
Yep, EL34 should do nicely.

If it were me, I think I'd try a small (ish) sealed box for the Alp12's. Possibly something around 12 litres might get you a natural roll-off around 100 to 150Hz. Thus reducing (or eliminating) the need for control on the Alps. Sorry I've no time to do calcs but its worth exploring this idea as there's a good chance it could simplify your build.

As a general guide, its usually best to use no active or passive control on Full Range drivers, rather to rely on optimised driver-cabinet combos to do the work. A cap can be added later is you need more frequency space for the woof.

It's not always possible to be so "purist" but trying to keep a set-up simple is usually a recipe for success.

Cheers

Mark.

[service_guy]

Hi Mark.
That was fast............
That 12l box sounds real easy to do.
So your are saying that...........

Possibly something around 12 litres might get you a natural roll-off around 100 to 150Hz. Thus reducing (or eliminating) the need for control on the Alps.

Sorry for the questions but I am new to the whole full range idea, so over excursion is not a problem when using the small sealed box?

Sorry I've no time to do calcs but its worth exploring this idea as there's a good chance it could simplify your build.

No need to do that, I can play with box sizes (I have lots of MDF and tools)
I am guessing that a narrow as possible baffle and rounded over is the best way to go?

Thanks again Mark for the fast response........... Customer service in action.
I do it everyday (I am a parts dept. manager at a large marine and powersport dealer).
Dave.

[planet10]

Attached is the FR sim of:
6 L Q ~0.707 (butterworth)
10.5 L Q ~ 0.577 (bessel)
16.5 L Q ~ 0.5

Once you decide on box size, it would be well worth the investment in good many-ply plywood. The resolution of the A12 is sufficient that MDF will bury the lowest level detail.

dave

[service_guy]

Hi.
Thanks Planet.
The MDF is cheap to work with, and you are correct that a good plywood is the way to go once I have decided on a box.
I am also guessing that these speakers are very cable dependant?

Thanks.
Dave.

[planet10]

Cables, speakers, amps are a system. The drivers are very high resolution so anything upstream & the synergy will play a role.

dave