Converting A7 cabinets into MLTL

**kwingylee** · March 2nd, 2016, 07:37 PM

After experience my buddy's A5s, I am now in the process of building my own. I will be using 1005B/288-16G and 825 or 828 cabinets. I want to explore the possibility of adding Electrovoice T350 tweeters to the mix and build the Hiraga A5X crossovers. Reading through the great designs, projects and associated comments from a number of you, including those for MLTLs with 416 and 604 series drivers, I am wondering if the 825/828 cabinets can be retrofited into one of GM's MLTL for 515 and 416-8A series drivers for my "A5" project? That would have the dual benefit of adding mass and bracing, as well producing additional lower octave of bass.

Hoping for expert advice from this group before I start this in the spring. Thanks in advance.

**Altec Best** · March 2nd, 2016, 09:48 PM

To technically call it a A5 you would need to use the 515 woofer with the rest of your components. I like the EV-T350 tweeters.You will need some kind of super tweeter to fill in above 15,000-16,000 Hz. IMHO. You can even use an 802 or 902.Cross it at around 7000 Hz.You should have a very nice sounding system with the components you plan on using..Those old 825,828 cabinets tend to be flimsy and need to be braced more thoroughly..Once GM sees the thread I'm sure he will chime in...

BTW- Welcome to the board ! I see you have joined along time ago but these are your first posts so have a look around !

GM · March 3rd, 2016, 02:16 AM

Not envisioning what you want, but the cab already is a MLTL except crudely expanding like a horn [I call them ML-horns, others, ML-TQWT] and if you remove the baffle boards it's a short BLH, so if you want it to play lower, just tune it lower same as me and some others have done and recommend as a standard tweak for HIFI/HT apps, though Per Hasling is the only one with a webpage that promotes the low tuning AFAIK: Hasling Audio Systems Denmark

I also recommend you use a 416 unless planning to drive it with a matching impedance amp or at least one with variable DF tone controls. Of course one can passively or digitally EQ it too, just that these old designs sound best overall when driven by the period correct electronics they were voiced with.

For something a bit different, search this forum for my posts on blocking off the back of the driver and using the rest of the cab for a 411 sealed 'sub' that I did to my old pair when it first came out in '71?, but were long since NLA when I posted it as a response to a request similar to yours, so folks used the JBL 2245 with all but one AFAIK being very pleased with the results. IIRC, the one who didn't had vented it, but had already sold them before I found out about it, so who knows? He might have liked it sealed. Unfortunately, the 2245 is NLA, so would have to do a bit of 'digging' to find a suitable replacement.

GM

**mah** · March 3rd, 2016, 03:56 AM

Kwingylee,

Here is something I posted when I had second thoughts about the Small Vott: http://www.hostboard.com/forums/f700...?highlight=mah

Follow the links in the original(first) post.

I hope it is useful.

Cheers, Marshall.

**kwingylee** · March 3rd, 2016, 08:53 AM

Originally Posted by Altec Best

To technically call it a A5 you would need to use the 515 woofer with the rest of your components. I like the EV-T350 tweeters.You will need some kind of super tweeter to fill in above 15,000-16,000 Hz. IMHO. You can even use an 802 or 902.Cross it at around 7000 Hz.You should have a very nice sounding system with the components you plan on using..Those old 825,828 cabinets tend to be flimsy and need to be braced more thoroughly..Once GM sees the thread I'm sure he will chime in...

BTW- Welcome to the board ! I see you have joined along time ago but these are your first posts so have a look around !

Thanks, I have been hanging out and the Lansing and audiokarma sites in the past. I have had my share of Altec gear, including M19s, Valencias, Flamencos and three sets of A7s. I want to convert one of my A7s into A5s by replacing the 511B/902-8B with the 1005B/288-16G. The said A7 came out of the Milwaukee Center for Performing Arts and are loaded with 515 woofers. maybe one of you can enlighten me on this but prior to acquiring these, I was under the impression that all A7s were 416/803 based, although I have seen them loaded with the 421s as well (1204Bs come to mind). I wasnt aware that A7s coming with 515s.

For the T350s, I have a few pairs laying around, I am thinking of laying them on top of the 828 cabinets and align them with the 288s, or should I mount them on a baffle somehow?

- - - Updated - - -

Originally Posted by GM

Not envisioning what you want, but the cab already is a MLTL except crudely expanding like a horn [I call them ML-horns, others, ML-TQWT] and if you remove the baffle boards it's a short BLH, so if you want it to play lower, just tune it lower same as me and some others have done and recommend as a standard tweak for HIFI/HT apps, though Per Hasling is the only one with a webpage that promotes the low tuning AFAIK: Hasling Audio Systems Denmark

I also recommend you use a 416 unless planning to drive it with a matching impedance amp or at least one with variable DF tone controls. Of course one can passively or digitally EQ it too, just that these old designs sound best overall when driven by the period correct electronics they were voiced with.

For something a bit different, search this forum for my posts on blocking off the back of the driver and using the rest of the cab for a 411 sealed 'sub' that I did to my old pair when it first came out in '71?, but were long since NLA when I posted it as a response to a request similar to yours, so folks used the JBL 2245 with all but one AFAIK being very pleased with the results. IIRC, the one who didn't had vented it, but had already sold them before I found out about it, so who knows? He might have liked it sealed. Unfortunately, the 2245 is NLA, so would have to do a bit of 'digging' to find a suitable replacement.

GM

GM are you referring to the thread by westend9 http://www.hostboard.com/forums/f700...ht=MLTL+416-8b ? A MLTL that consumed 12.5^3 feet of volume? I really like what he did, but I prefer to use the 515 for the A5 build. I can certainly use the 416-8A from my Flamencos to do what you have suggested with my 825 cabinets, but would like some help to partition the bracing to achieve similar results.

As far as adding a sub via the "leftover volume" wouldn't there be a huge sensitivity mismatch with a sealed sub? I reckon nowadays, a 15" woofer for a seal sub would be very hard to find, not to mention $$$$ expensive.

- - - Updated - - -

Originally Posted by mah

Kwingylee,

Here is something I posted when I had second thoughts about the Small Vott: http://www.hostboard.com/forums/f700...?highlight=mah

Follow the links in the original(first) post.

I hope it is useful.

Cheers, Marshall.

Marshall:
Great links, real useful. Clarification on a number of points that I wasnt aware of... such as the differences in internal volumes between the 825 and 828... come to think of it I dont know what I have now :-) Thanks.
I note that your last update was in 2012....any further developments since? Any additional upgrades? Any pictures?

GM · March 3rd, 2016, 06:43 PM

GM are you referring to the thread by westend9 http://www.hostboard.com/forums/f700...ht=MLTL+416-8b ? A MLTL that consumed 12.5^3 feet of volume? I really like what he did, but I prefer to use the 515 for the A5 build. I can certainly use the 416-8A from my Flamencos to do what you have suggested with my 825 cabinets, but would like some help to partition the bracing to achieve similar results.

As far as adding a sub via the "leftover volume" wouldn't there be a huge sensitivity mismatch with a sealed sub? I reckon nowadays, a 15" woofer for a seal sub would be very hard to find, not to mention $$$$ expensive.

No, a totally different [series of, as it turns out] thread[s] from many years ago where I 'stuffed' a 411 'sub' in a pair of DIY A7-500 [825] cabs. Didn't have any luck last night in a search, but today, no problem except it appears that I started it on another forum, but didn't say which and don't recall doing it.

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700/176025-a7s-subs.html?highlight=2245

Port thread: http://www.hostboard.com/forums/f700...highlight=2245

OK, use the 515 and either add a sub system or some form of EQ to get it to make any usable bass if tuned low, which usually will basically boil down to lowering speaker efficiency quite a bit. .

Yes, major mis-match even if you use GPA 411s, but then that's what bi-amping + high power handling is for.

GM

**kwingylee** · March 4th, 2016, 09:25 AM

Originally Posted by GM

No, a totally different [series of, as it turns out] thread[s] from many years ago where I 'stuffed' a 411 'sub' in a pair of DIY A7-500 [825] cabs. Didn't have any luck last night in a search, but today, no problem except it appears that I started it on another forum, but didn't say which and don't recall doing it.

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700...highlight=2245

http://www.hostboard.com/forums/f700/176025-a7s-subs.html?highlight=2245

Port thread: http://www.hostboard.com/forums/f700...highlight=2245

OK, use the 515 and either add a sub system or some form of EQ to get it to make any usable bass if tuned low, which usually will basically boil down to lowering speaker efficiency quite a bit. .

Yes, major mis-match even if you use GPA 411s, but then that's what bi-amping + high power handling is for.

GM

Thanks GM, I will check the links out. How did you like the "stuff" 411 solution and why did you get rid of yours?

I have never had luck with integrating subwoofers into HiFi systems, so I am a bit skeptical. My current main speakers hit hard into the 30s and I am happy with that. So I would be interested in tuning optoins from 35Hz to 20Hz...