Alpair 7.3's in BIB's

[Kenny Brant]

Curiosity got the best of me so I ordered a pair of 7.3 gold's from Madisound to see what they were like. I used the same BIB's that I originally had my 40-1354's in and then built a baffle and changed them out for a pair of Fostex F120A's. The BIB's are patterned off the original article from Terry Cain.

The opening for the 7.3's are 4 1/16 inch and the F120A's are 4 1/8 so the hole was close enough that I didn't have to make a new baffle.

I have about 110 hours on them and they do sound great. They have about the same bass as the F120A's do which is solid down to 40HZ and I think good to 35HZ, my test CD goes from 40HZ to 31.5HZ. The 31.5HZ signal is there but way down in volume just as it is with the F120A's.

The highs are there in spades, it goes higher than the F120A's, but the F120A's are still not bad. The 7.3's highs sound more integrated to the rest of the music than what the F120A's do. Both the 7.3's and the F120A's have good clear mids and lower mid bass.

What gets me is how the 7.3's draw you into the music. They don't sound metallic at all, just natural. They are very musical and honest sounding.

I tried all my usual receivers, preamps and amps with them. They all sound good but some better than others. I settled on tube preamp, tube amp combo. But my little Miniwatt N3 didn't have enough grunt to do the 7.3's justice (the Miniwatt did work OK on the F120A's). The amp that sounded really good with the 7.3's was my Magnavox 6BQ5 push pull. This amp didn't sound good to me with the F120A's. The 7.3's could tell me which 6EU7's sounded best in the Maggie which was the RCA's and not the Mullard's. Funny but with other speakers the Mullard's sound better. Go figure.

I was going to put the F120A's back in but I am just enjoying the 7.3's too much. I think they are great for the money. It is hard to go wrong buying them. Like any other small driver they have there limits volume wise but they still pump out quite a bit of volume. They image good also. Both the F120A's and the 7.3's sound good at low volume when you just want to lay back and relax when listening to music.

I've been so happy with both the F120A's and now the 7.3's in these cabinets I am about ready to sell all the rest of my speakers and just keep these. I just can't believe the sound stage, highs and lows these single drivers have. And a midrange to die for. And the word on the 7.3's are right, they do have good detail, not the best I've ever heard but right up there.

Get them, for the money you can't go wrong.

Kenny

[Kenny Brant]

Just to let everybody know I didn't just decide to throw the 7.3 Alpair into this BIB cabinet, I saw the Quali-Fi's Bach and decided to try it.

A bass reflex ported cabinet can be forced to reproduce lower frequencies by tuning the resonance lower and with a bigger cabinet, I did it years ago from a Speaker Builder article. It lowers the power rating of the driver and doesn't have the transient response of a smaller cabinet with higher tuned cabinet. It will cause a slump in response of the upper bass lower midrange. It is a trade off you have to accept to get lower frequency response. The BIB has the same trade offs.

I also figured that by putting this cabinet driver combination in a smaller room and in the corners and setting closer to the speakers will rise the bass and hopefully take care of the slump in response. It seemed to work well.
Everything is a compromise, I decided to compromise a little transient response and power handling and accept a little slump in lower mid range upper bass response to force this driver in this cabinet to a lower frequency response.

The cabinet is 7"x14"x70", the classic Terry Cain original cabinet.
People will tell me to use a sealed cabinet, or bass reflex or open baffle, but all these suggestions will force a woofer to be used which I didn't want to do, so this is why I decided to use the BIB's.

I am just experimenting. I don't play head banging music with this set up as it definitely has it's limits. You can hear it hit its limits in volume as you try to crank it, it starts to cone cry or distort, but is still pretty loud. If I used a woofer and crossed over the 7.3 I could get a lot more volume and go lower in frequency response.

Tell me what you think and what I might have missed, I am open to suggestions.

Kenny

[Godzilla]

>>> The opening for the 7.3's are 4 1/16 inch and the F120A's are 4 1/8 so the hole was close enough that I didn't have to make a new baffle.

That's good.

They are selling the BIB as a commercial design? I see they mention Scottmose...

I've swapped drivers in BIBs with good results. Some drivers will overwhelm in the bass but then i move them away from the corners. They are a flexible design.

BIBs are great when you don't want to use or have room for a subwoofer and love full range drivers. You won't get ultimate bass performance like you may with a powered sub but you will get about all the performance available from your full range driver all by itself.

I see you love tubes but have you tried any of the T-amps?

Zilla

[loninappleton]

This a good post since I've been wanting to try some new things with my BIB's.

Thanks for the detailed writeup. I have to measure my cutout and depth again but this looks like the order I've wanted to place.

One one BIB I started to recut for one of the most expensive Alpairs. It was a router experiment. Bit if I can use my good BIB with just a drop in it'll be a fresh project.

[Kenny Brant]

I see you love tubes but have you tried any of the T-amps?

Zilla

No, I haven't tried any T-amps, I know very little about them. Say Zilla what T-amps do you recommend?

Kenny

[Kenny Brant]

One BIB I started to re-cut for one of the most expensive Alpairs. It was a router experiment. But if I can use my good BIB with just a drop in it'll be a fresh project.

I built these BIB's for a RS 40-1354A and the opening was too big for the Fostex F120A's so I built a baffle for them. You can experiment with almost any driver that will fit just by building a new baffle. I figure a driver with similar size, fs, Qts and Vas should work in these enclosures.

Kenny

[planet10]

Originally Posted by Godzilla

They are selling the BIB as a commercial design? I see they mention Scottmose...

Kurt Neilson. The BIB is their own work. They have other designs licenced from Scott & some based on my stuff.

Cabinets made of bamboo.

dave

[Godzilla]

I like the Dayton T-amps (both the cheapie and more expensive metal cased one). I ordered the Lepai and sent it back because the knobs were so cheap.

Many of them look cool but I'm on a budget.

I'd love a bamboo cabinet! I want to buy a bamboo skateboard too.

Zilla

[Kenny Brant]

Originally Posted by Godzilla

I like the Dayton T-amps (both the cheapie and more expensive metal cased one). I ordered the Lepai and sent it back because the knobs were so cheap.

Many of them look cool but I'm on a budget.


Zilla

I am going to look into the Dayton T-amps (the cheapie one) and see what they are like. Curiosity always gets the best of me to at least try one.

Kenny

[Bob Brines]

I just got a Topping t-60. Haven't had much time to play with it, but it is quite a bit better than the Dayton DTA-100. The bass is deeper and clearer -- it uses good input caps -- and I think that the sound stage is wider, but I need more time.

Bob