My A7-500s. A journey

[Panomaniac]

"J'ai accord? l'enceinte comme un bass reflex, avec un ?vent laminaire de 6 cm de haut, 60 cm de large at 15,5 cm de profondeur (voir mesure d'imp?dance)."

Yes, looks like Dominique ended up with a BR tuning circa 33Hz

[VolvoHeretic]

Optimisation des ?vents d'une VOT

"J'ai accord? l'enceinte comme un bass reflex, avec un ?vent laminaire de 6 cm de haut, 60 cm de large at 15,5 cm de profondeur (voir mesure d'imp?dance)."

St?phane

Translation please.

[dominique-tanguy]

"I have tuned the port like a bass reflex, with a laminar vent 60 cm wide, 6cm height and 15.5 cm deep (See impedance measurement)".

This adjustment is of course valid for a given loudspeaker, but basic prinicple can be retained and surface as well. You will have to adjust the lenght of the port. You should also avoid very long "tunnel". It seems, for example, that a 416-8A would give a very different setting with a much longer port (and a lower F3).

Kind regards,

Dominique

[dominique-tanguy]

Dominique, could you tell me the dimensions of your bass port? I suppose it all depends on what drivers you are using and I still haven't wrapped my fingers around all of the Altec parts numbers. My A7-500 bought new in 1976 doesn't show up in any old literature. It is a plywood (3/4" plywood) enclosure with the small removable bass driver rear panel, the horn was installed in the front port, and it looks like your A7, except it has a routered out round cornered cloth covered port panel. It came with the 416-8A woofer, N501-8A crossover, I think 511B horn but since it is now enclosed in a sealed horn box and I can't see the horn driver, I will guess has the 802D compression driver. Make sence?

Dear Volvoheretic,
I strongly recommend that you try the "serie" Xover I mentionned before. Very easy to build and could improve a lot your system...
Regards,
Dominique

[Panomaniac]

Dominique. I"m going to have to try the hanging felt curtain trick. I can't remember if we used in in Hiraga's A5, but it was common in a lot of is other work. You seem to have gotten such good results it's worth try.

With my strange 0.44 Qts 416-8As, your 33Hz box tuning may give a 5dB hump at the bottom end. That could actually be a big help with my rig.

[VolvoHeretic]

So which woofer is this?

How come Photo Bucket's thumbnail sucks?

[Altec Best]

So which woofer is this?

How come Photo Bucket's thumbnail sucks?

It is a 416-A.

In photobucket copy the direct link second one down in the drop down menu and then click the insert image link in hostboard.Paste it in the box and uncheck the retrieve image link,insert image and your done.Like This !

[VolvoHeretic]

It is a 416-A.Could also be a 803B,does it have a red or black cloth surround.But Most likely a 416A though.

Thanks Altec Best. It has a black surround. I wonder why they would put a 16 ohm speaker in my A7's?

[Altec Best]

Thanks Altec Best. It has a black surround. I wonder why they would put a 16 ohm speaker in my A7's?

I had changed my post ,you must have quoted me before I could change it.The 803B was a hammertone green and not the flat green of your 416.So I was correcting my post when you quoted me.

For your question they wouldn't if it's an 8 ohm speaker.IME someone must have thrown a replacement in it not knowing to keep them all 8 ohm.It wouldn't have come that way from the factory unless, it a dual woofer con-fig cabinet, speakers wired in parallel to acheive an 8 ohm load.For your A7, who knows ? I would assume that it was just a replacement, albeit the wrong replacement.

[VolvoHeretic]

Both woofers are the same. These were bought brand new. Next weekend, I will verify exactly what crossover, horn and driver is also in these. Curious, That must be why I was abe to crank up the DC300A so high. What's it going to sound like when I hook these up in parallel with the 8 ohm Peavey T300s. I also wounder how I wire up the 8-8ohm Piezos.