Driver/enclosure to complement Alpair 10.2 FR Pensil in a FAST system?

[OlavHaal]

Happy New Year all!
To all diy-er who has a helping hand or head: me and a friend ordered our Alp10.2 today and I have started building my cab. But my friend want to use it either as a part of his Jamo. His Jamo Concert VII has a subbass from 24-150 Hz and he want to keep that as a FAST! But if he swap the midrange and tweeter he will have a volum around 10-12 liter. I use 18-19 liter for mine ported.

But then 2 questions arises: Go for a ported or a closed box. Nr2: Run Alp10.2 Fullrange and with a filter for the Subbas(it`s a very good bass in that Jamo) - or with a crossover at 150 Hz so the Alpair is released for the heaviest bass?

Hope this was an easy case for someone who is more versed in this than 2 relatively newcomers in Norway.

Greetings to all.

Olav

[planet10]

FAST should work well. If you keep the A10.2 sealed you can just use the 2nd order roll-off as all, or part of, the high pass filer.

9.2 liter sealed gives a Q of 0.707 with an F3 of 71 Hz. If that is too low you can actively filter it (you don't want to use passive that low)

dave

[OlavHaal]

Yea - my friend say he will run them paralell! 7.2 in paralell w. 6 ohm gives me just under 4 ohm so that should be ok! And he have a crossover to the sub. So I think we try that for a while and then insert a filter on the Alp20.2 when and if the output from Alp10 will interfere with the subbass.

Time will tell - and the joy of trying is just ahead in the future.

Be back when our projects is more complete.

Ol

[bro]

Originally Posted by southernoise

I've just bought more polyfill for the cabinet. Stuffed it to the right prescribe amount 0.75 lb/ft3 which translate to around 0.81kg for the Pensil 10.2. Quite packed!

WOW, now the bass is tight and solid. Played Portishead - Dummy and I could actually "feel" the bass while the vocals and instruments remains clear and defined. I'm really impressed with Mark's Alpairs! I wasn't expecting this when I decided to go the full range way.

I'm happy.

Congrats to your beautiful pair of Alpairs!

Could you kindly share your sources of material for the cabinets? I want to be happy too!

I've been running Alpair 7 on 7 litre Mission 780 bookshelves (tweeter disconnected) and find the bass lacking. I've reworked the 780 baffle to fit the A7. Though I've tried to seal all possible leaks, my work is kinda shabby. So thinking of going for Pensil 7. I wonder if void free birch ply is expensive here.

Also, besides polyfill, did you use any foam directly behind the drivers?

Thanks! Cheers!

[norman bates]

I'd recommend a large box (.5-1ft3). That way the pressure in the box does not limit what the driver wants to do (similar to a lack of rear pressure on the cone when using an open baffle).

Foam or fill is tricky, usually I have to add, to add, then subtract to get it right.

Norman

[southernoise]

Hi Bro,

I got a contact from a carpenter at Sungei Kadut area that does speaker cabs for many shops here in Singapore, eg Leda/Martin. IMHO, he is kinda pricey but he sure knows what he is doing. I'm not sure if I'm allowed to post contacts here in the forum so drop me a pm if you want his contact.

If I were to do it all over again, I'd just get some precut marine ply and do it up at home. Pensils are not that complex to build maybe just the driver cutout.

Else you may want to check with Tony from Twin Audio, Hong Kong in this forum. His prebuilt solid wood cabs are pretty well made. Just received a CHR70 bass reflex kit from him.

I did not use any foam behind the drivers, just carefully stuff the polyfill so that it does not touch the drivers.

Cheers,

Edwin

Originally Posted by bro

Congrats to your beautiful pair of Alpairs!

Could you kindly share your sources of material for the cabinets? I want to be happy too!

I've been running Alpair 7 on 7 litre Mission 780 bookshelves (tweeter disconnected) and find the bass lacking. I've reworked the 780 baffle to fit the A7. Though I've tried to seal all possible leaks, my work is kinda shabby. So thinking of going for Pensil 7. I wonder if void free birch ply is expensive here.

Also, besides polyfill, did you use any foam directly behind the drivers?

Thanks! Cheers!

[bro]

Hi Norman,
Thanks for the tips. Any pointers on what i can do to achieve better soundstage?
(btw, your name is very familiar. Do you own a motel?)

Hi Edwin(Southernoise),
Thanks for the info. I'll pm you for the contact and check out Tony's postings.

Cheerios all!

[OlavHaal]

Hi all or someone who know!

Me and my friend got our 4 drivers today(Alp10.2 looks SO great) - but my friend wonder if he can use the Advance Acoustic Integrated - and split the pre so the Internal Power Amp(75Watt in 8ohm)in Advance runs the Alp10? And the other split signal from the pre is fed into an old Nikko Power Amp with 120Watt in 4 ohm - that will feed the Jamo Sub in his old Speaker?

I tell him there can be some trouble with unbalanced signal to 2 Power Amp. And he will not control the volume since they are so different in power/load.

Can he proceed with his project as he planned or as we first planned with the crossover (120 Hz) to the Jamo - and run Alp10.2 Fullrange in the old upper compartment of the Jamo Concerto( which will be made bigger)?

We will be VERY grateful for some good/sound advice on this case.

And we will display som good photos from our projects when it is more finished.

Greatings to all.

Olav

[planet10]

He'd need an XO between the pre & the amps. Does the AA already have a pre-poweramp loop?

dave

[OlavHaal]

Hi Dave!

Tnx for quick respons!
As I remember(while ago since I did see his combo) -
The Advance Acoustic only has a link from the pre to the power, so one can use the preout to another poweramplifier. And then he has to use a cabel and split the cabel towards two poweamps(the Advance Acoustics own and the other old Nikko)
And I think it will be difficult to control the volume and the symmetry between them. And I`m not shure if the 3 units can handle the unbalance?

Olav