Porting Altec Santiago's (878B)

[wlk]

I recently aquired a pair of Altec Lansing Santiago's (878B) circa 1974 / 75 with the following components:

HF Drivers 806-8B
Horns 811B
LF Drivers 411-8A (Recently refoamed)
Xovers N801-8A
HF Attenuators 30904

Is it possible to increase the bass output and quicken the bass response by porting the cabinet?

If it is possible, where should the port be located (front or back) and what are the correct port dimensions?

What do you think the ported cabinet would sound like?

Could a JBL LF driver such as a 2231 or 2235 be used to replace the Altec 411-8A?

What would be the difference in sound between the Altec and JBL LF drivers?

[spkrman57]

And the 2235 requires a minimum of 4 cu ft for reflex use.

What is wrong with the 411 driver? It is a good driver for the purpose intended.


You could use a 2226 driver ported for plenty of midbass punch, but bottom octave response is not as low as using the 411's!

Just my 2 cents worth here!

Ron

[Don McRitchie]

The Santiago has roughly the same interior volume as the L300 and may even be a bit larger. As a former Santiago owner, I think I know what wlk is getting at. The 411 bass driver always struck me as underdamped with a somewhat bloated character. It definitely played lower than the similar 416 based Valencia. However, in my opinion it did not have anywhere near the same level of bass articulation and definition.

I have been told that porting the 411 does not work well due to the underdamped suspension, but I am not aware of anyone that tried it. Replacing the 411 with a 2235 would be an interesting experiment. They are very close in sensitivity such that the 801 cross-over could likely still be used. You would have to calculate the exact interior volume (making sure you subtract the fairly substantial horn/driver volume) and then design an appropriate tuning and port design. I would port it out the back just in case you decided you wanted to resell the system at some point with the original components. It would be cosmetically easier to fix in the back.

[edgewound]

I'm not familiar with the Santiago and how much damping material is in the enclosure...but maybe try this. Before porting the cabinet and changing the driver, add more stuffing to the cabinet to dampen the woofer suspension. A sealed enclosure usually calls for a driver with a Qts of greater than .5, so altering the acoustic compliance of the air spring in the enclosure might yield satisfactory results for you. It's probably worth a try....fiberglass or dacron batting is cheap and you won't alter the cosmetics of the box. Don't be afraid to stuff it full....you can always take it out. Two things you'll notice when you try it. The woofer will seem less compliant...or tighter if you will....and the virtual volume of the box will increase up to 20% resulting in lower bass extension. Of course....you might not like it....lol.

You might also want to try a different amp...one that has a damping factor of greater than 500 with lots of power reserve...it's quite ear opening...that is if you haven't already tried that.

Thanks,

Edgewound

[Lancer]

I'm not going to quote anyone. Instead I'm going to be REALLY lazy and let Wayne explain his perspective with respect to damping

http://www.audioroundtable.com/PiSpe...ages/2062.html










BTW we need to get some better parameters on some of these drivers...

[wlk]

Thanks to everybody for all the excellent information and suggestions.

Please keep the information and suggestions coming.

My desire to improve the bass output and speed of the Altecs is based upon comparissons with several pairs of JBL's that I own including L220s, L100Ts and L112s. The comparrison may be a bit unfair but the Altecs have a magical midrange and I would like to improve them.

Last night after my post I thought I would take a closer look at the Altecs and see if I could spot any potential areas to upgrade in order to improve the bass. These were some of the things that I noticed:

The two inductors in the Xover are ferrite core and use small wire.
All capacitors are original and in questionable condition.
The internal wiring is original and small gauge.
The seal around the LF driver is questionable.
There is no seal around the HF horn.
All drivers look great.
LF drivers have been refoamed - job is excellent

Another thing that I notice was when I played the Altecs with the Xover connected but unscrewed from the cabinet (sitting on top the cabinet) the bass became extremely unfocused and flabby. Granted the opening for the Xover is not a tuned port but it may give some indication of how the LF driver would sound in a ported cabinet. Maybe the 411-8A cannot be used in a ported cabinet.

To answer the question regarding the amp that I am using, it is a JBL MPX 300 (made by QSC) which is rated at 200 watts at 8 ohms with a damping factor of greater than 200.

Thanks
WLK

[wlk]

I started this thread about a week ago because I had purchased a pair of Altec Santiagos and I requested help in porting the cabinets because I was not satisfied with the amount or quality of the bass produced by the 411-8A LF driver. I got numerous responses providing excellent informations and suggestions. Thanks to all.

I have been playing the Santiagos for about twelve hours a day for the past week at medium volumes and the sound of the spekers have changed significantly. They now sound wonderful. The high frequencies are clearer and more articulated and the low frequencies are louder and more controlled. I know that this is not a figment of my imagination because I have a set of JBL L100Ts in the same room connected to an identical amp, connected to the same preamp and same DVD / CD player and I am able to do direct before, during and after comparisons. A week ago the Santiagos had less bass and the highs were less lively than the L100Ts. Now the reverse is true.

The Santiagos had sat in storage for a very long time with the previous owner.

Is the difference in sound due to the spiders and suspensions losening up?

Is the difference in sound due to the capacitors reforming?

Is there any type of reforming that may have occurred with the inductors?

Is there a lesson to be learned here for all of us who like vintage speakers?

Regards
WLK

[speakerdave]

Is the difference in sound due to the spiders and suspensions losening up?

Maybe it's because the spiders have been LEAVING.

David

[Lancer]

Maybe it's because the spiders have been LEAVING.

David

That's exactly what I was thinking.

[speakerdave]

"Geesh! Doesn't this guy have any quiet records? I'm outa here!"