What subwoofer to mate to VOTT A5?

[Alberto86]

Hello all,

I’m putting together a A5 system. So far I got a pair of 515-8G currently at GPA for re coning and a pair of 288-8L. I’ll most likely send those to GPA for general restoration As well.

For the cabinets I’m looking for a pair of 828 and as for the horn a pair of 1505B.

i hear that the 828 cabinets are a great cab above 100hz but really lack the low end. As I’m working on this project, I may consider to add one or two subwoofers. I looked into vintage altec cabinets as split 210, 816 etc but it looks like nothing from that era will give me what I’m looking for , 25hz to 100ish hz solid bass.

As per amplification I have a McIntosh MX110Z feeding a mc225 for the A5 speakers. For the subwoofer(s) the MX110Z has a mono output that I can use to feed a solid state mc250.

anybody has any idea in what direction I should be looking towards? I’d prefer to stick to altec cabs and drivers if possible to match the tone of the main speakers.

thanks a lot in advance.

AB

 

[bowtie427ss]

i hear that the 828 cabinets are a great cab above 100hz but really lack the low end.

50-55hz is a more realistic cutoff.

I’d prefer to stick to altec cabs and drivers if possible to match the tone of the main speakers.

Altec(under EV) made 1 woofer/system that fits your bill, 8182. They made a few hundred of them in total. I haven't seen even the raw driver for sale in several years. But, i don't actively search for them anymore either.

An honest 20hz subwoofer.

https://www.hifido.co.jp/sold/15-88753-55949-00.html?LNG=E

I'd probably be looking at 18 inch cinema subwoofers from Just Big and Loud, they made at least 1 model every year for the last 3 decades, and a couple will actually go down into the 20's without processing and kilowatts.

 

[kwkshift]

For a large and ultra-high output subwoofer to go with those speakers, I'd consider an offering from Danley, JTR or Bill Fitzmaurice but with the aesthetics and veneer to match the VOTT speakers. Bill Fitzmaurice sells the designs which you can give to a professional cabinet maker for completion in your choice of finish. The Danley and JTR products would probably have to be custom ordered to get the finish you desire. There may be other options out there, but those are just the ones I thought of first.

 

[Tom Brennan]

When I had A5s I used a pair of JBL Pro 4648 movie bass bins, each with a pair of 2226 woofers. With the 6db of boost at 30hz from a Parts Express plate amp and wall placement they were flat to 25hz and tracked the dynamics of the Altecs. Yeah, I know you're not supposed to EQ vented systems below resonance but the JBLs took it in stride. I see used 4648s selling for quite reasonable prices.

 

[seamas]

JBL 4645

 

[EarlK]

So now that I had output, I set off to trim it out. I've settled on 53Hz. The volume is about 8.5 of 10. At that level I can't 'hear' the subs when they're on, but the bottom drops out when they're off. That's the way I want it. Like adding salt to my soup. I want to bring out the flavor, but I don't want to taste the salt.

The blend is uncanny. My old KLH gave up some sub sonics, but it sounded dry and monotone. More of a vibration than a musical note. These sound sweet and smooth and very musical. I really can't tell where my Altecs end and these begin...until I turn off the Crown. Then..."oh, where'd all that nice deep bass go?" When I turn it back on, I can't really hear the bass come back...until I turn it off again. Nice.

I have always appreciated and enjoyed AlanCohen (s) posts and his threads about his journeys to achieve Altec nirvana.

These journeys are chronicled over at Altec Users Board ( HUB ).

Here's the relevant thread called Subwoofer to Support Your Altecs

He's running A5's.

I would follow his lead for a subwoofer project.

It's a good idea to read all his threads to understand how he got to where he's currently at.

 

[Pete B]

When I had A5s I used a pair of JBL Pro 4648 movie bass bins, each with a pair of 2226 woofers. With the 6db of boost at 30hz from a Parts Express plate amp and wall placement they were flat to 25hz and tracked the dynamics of the Altecs. Yeah, I know you're not supposed to EQ vented systems below resonance but the JBLs took it in stride. I see used 4648s selling for quite reasonable prices.
View attachment 2874815

It is completely valid to EQ a vented system with the peak at the box tuning frequency because
cone displacement is at a minimum and the system will take a lot of boost. If the system is
about 9dB down at box tuning then +6dB of boost will make it 3 dB down and you'll probably
be pretty close to a Thiel B6 alignment. Best is to use a peaked high pass filter so that you
reject LF content below tuning where excursion goes back up.
If the box tuning is significantly higher it would be best to drop the box tuning to where you want the boost.

 

[twiiii]

Professional 5628 JBL's using dual 18 inch long throw woofers. There are other for sure if you don't use the full potential of the A5 and which woofers are in the 825 bass enclosure. Altec/EV also made their own dual 18 inch subs for use when Discos were popular. I think they used 3182 woofers rated around 600 watts RMS long term. We use to power them with QCS amps with built in limiting to prevent clipping.

 

[billyz]

Sorry, I laughed. When I first heard a set of A7's in a friends home we never knew they needed a Sub Woofer. And Never missed one. Of course I don't think they were even invented yet.

 

[analog addict]

I'm with Tom, more or less. I use 2 JBL 4685s each loaded with a pair of JBL 2225Hs. Each is run by an Ashly FTX 2000 series amp, good for 800 watts bridged into one channel. Signal is off a center channel output on the preamp, which then is run through an active crossover, courtesy of Mr. Brennan.

Untitled by analog addict, on Flickr

Untitled by analog addict, on Flickr