Altec & TAD drivers

[teddy.edwards1]

I'm using Altec 828 and 816 cabinets loaded with Altec 515-8GHP, and I also have some Altec 421-8LF drivers too.
I know the sound of these, and how much SPL they generate...
...but what if I use TAD 1603's?
What can i expect?
It would be an 18bd xover at 800hz with no LF cutoff.


thanks
tom

[Earl K]

> You can expect a "softer, less dynamic sound" when switching to TAD from either of those Altec models .

> That said, the one person on this site who could really expound ( & expand ) on doing swaps like this , passed away a year & a half ago ( RIP Scott Fitlin ) .

> You do realize that both of the cabinet designs which you built ( 816 & 828 ) are mid-range heavy, right ?

> If you want more bass ( & want to match the dynamics of what you currently get from those cabinets ) , build a large bass horn // OTOH, if you don't have the room for horn loaded sub then build a Bass-Reflex type, housing an 18" woofer of some sort ( 8 -10 cu ft if it's JBL ) .

:)

[richluvsound]

Teddy


.... the 1603 is used in PA applications . Not really sensitive enough for home use ... I think Widget could be a great help with all things TAD . He may have suggestions . Maybe shoot him a PM

Good Luck , Rich

[teddy.edwards1]

Thanks Earl,

Yep, sure do miss Scott, found this from him on the subject:

http://www.audioheritage.org/vbulletin/showthread.php?7574-JBL-2225-vs-Altec-515



In the existing system I have there are 4 x 515-8GHP and 2 x 421-8LF - in 828 and 826 cabinets respectively.

The subs are crossed over at 100Hz and go through a DBX100 boom box

But I still feel there is something missing 100-200Hz
This is why I'm thinking about the TAD 1603's

The set up is intended for something between a massive home hi-fi and a nightclub sound system.

What I want to know is will the TAD's be able to satisfy the need for extra the 100-200Hz ?
If I'm going to invest in them then it's going to cost a lot to get 'em re-coned and shipped to the UK!

Scotty mentions in the post that he would not mix different drivers in the system, but says it can work. Maybe one day if I build more cabinets I can get the niceness of the 515's AND the extra power of the TAD's?


Thanks
Tom




> You can expect a "softer, less dynamic sound" when switching to TAD from either of those Altec models .

> That said, the one person on this site who could really expound ( & expand ) on doing swaps like this , passed away a year & a half ago ( RIP Scott Fitlin ) .

> You do realize that both of the cabinet designs which you built ( 816 & 828 ) are mid-range heavy, right ?

> If you want more bass ( & want to match the dynamics of what you currently get from those cabinets ) , build a large bass horn // OTOH, if you don't have the room for horn loaded sub then build a Bass-Reflex type, housing an 18" woofer of some sort ( 8 -10 cu ft if it's JBL ) .

:)

[teddy.edwards1]

Teddy


.... the 1603 is used in PA applications . Not really sensitive enough for home use ... I think Widget could be a great help with all things TAD . He may have suggestions . Maybe shoot him a PM

Good Luck , Rich


thanks Rich... the setup is neither home use or PA. Or should I say it's both... I do feel a little more bass is needed in the 100hz-200hz area. I would very much like to see what Mr Widget has to say - I'll get on it...
the 515's are wonderfully detailed and just the kind of sound I want, but there are some who think a boost in output is needed... but I still want that kind of sound... what do you think? Other options? Maybe something cheaper than the TAD's?!!

Tom


Tom

[richluvsound]

Tom,

It would be useful to explain how you envisage using the components ... FQ range ?

Tads could be horn loaded ,but not really for LM duty ... wasted there !

Rich

[teddy.edwards1]

Tom,

It would be useful to explain how you envisage using the components ... FQ range ?

Tads could be horn loaded ,but not really for LM duty ... wasted there !

Rich

FQ range? LM duty?
sorry mate, not up to speed with the abbreviations!
but would love to explain so i can get some help... where should i start?

Tom

[Lee in Montreal]

What can i expect?

Simply compare their Thiele/Small specs. That should tell you a lot. Fs, Vas, Qts mainly.

[speakerdave]

Maybe it's the cabinets. Aren't they rather known for having a corkscrew response in the region of concern?

[teddy.edwards1]

Simply compare their Thiele/Small specs. That should tell you a lot. Fs, Vas, Qts mainly.

Thanks Lee... loving the Waldorf project by the way...

Theile/Samll

Fs TAD 28Hz ALTEC 37Hz
Qts TAD 0.34 ALTEC 0.187
Vas TAD 304L ALTEC 342L (I think the 828's are just under 300L in volume)
Xmax TAD 8mm ALTEX 3mm

The higher Qts of the TAD would indicate a more pronounced low frequency output, but the 515 would deliver a more controlled 'tighter' output? I'm quite new to understanding the damping effects of electrical/mechanical or overall Q...
Presumably the lowe free air resonance of the TAD would indicated more low end power, and the Xmax being higher also would?

This still doesn't tell me about the character of the sound so much though, does it? Perhaps you can help me with further insight?





Thanks
Tom

[richluvsound]

Thanks Lee... loving the Waldorf project by the way...

Theile/Samll

Fs TAD 28Hz ALTEC 37Hz
Qts TAD 0.34 ALTEC 0.187
Vas TAD 304L ALTEC 342L (I think the 828's are just under 300L in volume)
Xmax TAD 8mm ALTEX 3mm

The higher Qts of the TAD would indicate a more pronounced low frequency output, but the 515 would deliver a more controlled 'tighter' output? I'm quite new to understanding the damping effects of electrical/mechanical or overall Q...
Presumably the lowe free air resonance of the TAD would indicated more low end power, and the Xmax being higher also would?

This still doesn't tell me about the character of the sound so much though, does it? Perhaps you can help me with further insight?





Thanks
Tom

I would use the TAD on Low F , the Altec Low - Mid and the horns above with a 2405 UHF . The Crossover points are roughly :

Tad 15's - 28 Htz to 300 ish

Altec 15's -280 Htz to 700 ish .... A bit wasted . JBL 2123 or 2122 would be better in terms of size IMHO

Altec CD - 700 to 7.0 Khtz

JBL 2405 0r 2402 . 7 to 18-20K .

Sonics are too dependant on amp , cab , and crossover design to offer any opinion . I would look to something like LAB Gruppen , Mc2 or the Crown K2 running the Tads. You have the scope t EQ what ever you want really !

Hope this helps . There are people here with the knowledge to help you if you give them all the info they need :)

Rich

[teddy.edwards1]

OK, I see.
The system is comprised of:

Altec 828 w/Altec 515 drivers
20-800hz

JBL 2395 w/2441 driver
800hz-7khz

JBL 2405
7khz-20khz

These are in a 3 way active crossover setup using 18db/oct butterworth filters.

In addition to the above there is optional sub reinforcement crossed at 100hz - 18db/oct.

The drivers would be powered by BGW GTA amplifiers


Got to say I never thought about introducing a 4th driver into the full range... thought the TADs might be a good substitute for the Altec drivers, not a complement...


Tom







I would use the TAD on Low F , the Altec Low - Mid and the horns above with a 2405 UHF . The Crossover points are roughly :

Tad 15's - 28 Htz to 300 ish

Altec 15's -280 Htz to 700 ish .... A bit wasted . JBL 2123 or 2122 would be better in terms of size IMHO

Altec CD - 700 to 7.0 Khtz

JBL 2405 0r 2402 . 7 to 18-20K .

Sonics are too dependant on amp , cab , and crossover design to offer any opinion . I would look to something like LAB Gruppen , Mc2 or the Crown K2 running the Tads. You have the scope t EQ what ever you want really !

Hope this helps . There are people here with the knowledge to help you if you give them all the info they need :)

Rich

[teddy.edwards1]

Whilst I'm at it I might as well list the amps as you're right it does have a big effect.

Altec 515-8GHP - BGW GTA
JBL 2441 - BGW250
JBL2405 - Crown D75

Thanks
Tom

[teddy.edwards1]

on a more practical level, does anyone know if the share the same mounting dimensions?
looks to me like they have a different diameter for the bolt holes?

tom

[richluvsound]

Tads are 16"

[louped garouv]

on a more practical level, does anyone know if the share the same mounting dimensions?
looks to me like they have a different diameter for the bolt holes?

tom

i've installed 1601As in an 825/828 homebrew box that used to house 515Bs... :)


i've been told that it helps to add a cork gasket or something, between the driver face and the rear of the baffle -- to keep the cone from slapping the cabinet... if you drive them hard...

i've not experienced this issue personally, even though I did not have the gasket installed when I had the 825s in the house.... but i did not listen at crazy levels either...

[Earl K]

> Here's one of Scott's older posts (http://www.audioheritage.org/vbulletin/showthread.php?20088-Explain-Tad-woofers-Help&p=201428&viewfull=1#post201428) where he compares the sound of his TAD 1603s ( in his midbass cabinets / which were 815, 816 & even 817s , I think ) to other brands of speakers .

:)

[Mr. Widget]

> Here's one of Scott's older posts (http://www.audioheritage.org/vbulletin/showthread.php?20088-Explain-Tad-woofers-Help&p=201428&viewfull=1#post201428) where he compares the sound of his TAD 1603s ( in his midbass cabinets / which were 815, 816 & even 817s , I think ) to other brands of speakers .

:)Thanks Earl... though it is saddening. I remember getting phone calls from Scott at all hours after one of his change outs, he was so enthusiastic, it was contagious. Truly missed.


Widget

[Earl K]

Thanks Earl... though it is saddening. I remember getting phone calls from Scott at all hours after one of his change outs, he was so enthusiastic, it was contagious. Truly missed.

Your Welcome :)

I too miss Scott along with his all contributions to this forum .

He was in a truly unique position in having a large horn loaded commercial system that he was very intimate with . Reading his impressions of the equipment change-outs was always interesting ( for a live guy , such as myself ). He said a few things in these areas ( the details long lost in my memory ) that let me know we were really on the same page . I regret never getting to his place . Yes, he is really missed .

<> EarlK

[teddy.edwards1]

i've installed 1601As in an 825/828 homebrew box that used to house 515Bs... :)


i've been told that it helps to add a cork gasket or something, between the driver face and the rear of the baffle -- to keep the cone from slapping the cabinet... if you drive them hard...

i've not experienced this issue personally, even though I did not have the gasket installed when I had the 825s in the house.... but i did not listen at crazy levels either...

yeah, got some TAD 1601B drivers and this is a problem... look at the difference between the altec gasket on the left and the TAD on the right...


55930


so it looks like i've got 6 or 7 mm increase in gasket thickness - and that's before i've allowed for any difference in cone excursion between the TADs and the Altecs.

I can look at the cone excursion specs but that won't tell me about the speaker surround movement, which is the bit which may touch the baffle - any thoughts on this, or will it be ok?

the TADs sound amazing at low levels though, but when you turn them up the surround definitely touches the baffle board...


thanks
tom

[teddy.edwards1]

yeeeshhh... really?
nobody got any advice on this matter?
I tought that this forum would be THE place to turn for the TAD/Altec combo question...



Thanks
Tom




yeah, got some TAD 1601B drivers and this is a problem... look at the difference between the altec gasket on the left and the TAD on the right...


55930


so it looks like i've got 6 or 7 mm increase in gasket thickness - and that's before i've allowed for any difference in cone excursion between the TADs and the Altecs.

I can look at the cone excursion specs but that won't tell me about the speaker surround movement, which is the bit which may touch the baffle - any thoughts on this, or will it be ok?

the TADs sound amazing at low levels though, but when you turn them up the surround definitely touches the baffle board...


thanks
tom

[Lee in Montreal]

yeeeshhh... really?
nobody got any advice on this matter?
I tought that this forum would be THE place to turn for the TAD/Altec combo question...

:confused:

[richluvsound]

Teddy ,

could you not have some rings cut from 6mm Aluminium to make up the difference ? You can have the bolt holes cut at the same time !

Rich.

BTW ... I'm looking for a 1603 basket if you hear of anything ?

[Sundown]

yeeeshhh... really?
nobody got any advice on this matter?
I tought that this forum would be THE place to turn for the TAD/Altec combo question...



Thanks
Tom

Wow!? Just go Mcguyver and figure something out. I'm sure you can figure out a way to make a gasket, check a local hardware store

[4313B]

Wow!? Just go Mcguyver and figure something out. I'm sure you can figure out a way to make a gasket, check a local hardware storeDoesn't he blow shit up by mistake though?

Oh wait, that's MacGruber. :o:

[Sundown]

Doesn't he blow shit up by mistake though?

Oh wait, that's MacGruber. :o:

Haha

[Lee in Montreal]

Front mounting the woofers allows to avoid any problem with excursion and gasket thickness. And if you really need to make a 1/4" gasket to clear the cone, then grab a sheet of 1/4" Massonite and a router. 5 minutes later you will have a nice pair of spacers...

[louped garouv]

Or you could also source rubber gaskets for mounting speaker grills...

[teddy.edwards1]

Teddy ,

could you not have some rings cut from 6mm Aluminium to make up the difference ? You can have the bolt holes cut at the same time !

Rich.

BTW ... I'm looking for a 1603 basket if you hear of anything ?



i recently got some 1603 baskets with the cones totally wrecked for £100 each on ebay, they were in the UK. I see there's 1 x 1603 on ebay (http://www.ebay.co.uk/itm/TAD-TL-1603-15-Speaker-/330750166072?pt=LH_DefaultDomain_0&hash=item4d023f0438) and whilst it would come in at £200 from the US it does have a working (but non-original) cone. in the uk it seems there are very few of these (?) in fact you can't even buy them from pioneer

regrding the aluminium, i think that would be the best thing because it is rigid and will not change any of the resonnance of the speaker. i was worried that just using rubber gasket would create a springy effect and change the qualities of the speaker.

i can get a friend to laser cut (so lazy!) some 6mm plywood rings to use as a slightly cheaper alternative maybe? could also put a bit of 1mm neoprene to make them airtight where they meet the baffle. don't want to fix them permanently. there won't be much difference between using ply and using aluminium though will there?

by the way, when you say you want a 1603 basket - are you going to recone it yourself or do you know someone who is competent, if so, where's the recone kit from? just interested if you can get em in the uk - every tech i speak to has not heard (of) them!
i still need to get 2 x 1603 reconed. i know someone who used to work for gauss that could maybe do it... but if you know of anyone... wouldn't mind trying myself but this is a bit of an expensive start point.

oh also: 1603 orig. diaphragms:
http://www.ebay.co.uk/itm/TAD-DP-1603-/190645342377?pt=LH_DefaultDomain_0&hash=item2c635910a9

thanks
tom

[teddy.edwards1]

Front mounting the woofers allows to avoid any problem with excursion and gasket thickness. And if you really need to make a 1/4" gasket to clear the cone, then grab a sheet of 1/4" Massonite and a router. 5 minutes later you will have a nice pair of spacers...

unfortunately you can't mount the speaker in front of the baffle on the Altec voice of theatres.

with the spacers you describe, assuming i don't want to glue them (so i can still swap other drivers in), would you put some sort of gasket on the spacer too?

is masonite what we call hardboard in the uk? sooth one side and textured fibres on the other? would this be better than ply do you think?

ta
tom

[teddy.edwards1]

Wow!? Just go Mcguyver and figure something out. I'm sure you can figure out a way to make a gasket, check a local hardware store

yeah i can probably figure a lot of stuff out, but there's nothing like finding out off someone who knows or has come across this particular problem before... thanks for the help though.

[teddy.edwards1]

Or you could also source rubber gaskets for mounting speaker grills...

i actually did request 2 spare gaskets with the tad1601b that i got. but i was warned off doing this by someone who used to work for a spkr mfr years ago. they said that the elastic modulus of the gasket it important. and if you use 3 instead of 1 (even if it is the 'official' gasket from the mfr) then you could affect things in the LF. This does seem a little over the top. but i also want to do this right!
the gasket on the altec drivers is so squishy compared with the TAD gasket... all these things must have an effect.

given that i will not be overdriving the speakers is there any way to determine from their specification exactly how far the speaker will travel forward at max displacement?


tom

[richluvsound]

i recently got some 1603 baskets with the cones totally wrecked for £100 each on ebay, they were in the UK. I see there's 1 x 1603 on ebay (http://www.ebay.co.uk/itm/TAD-TL-1603-15-Speaker-/330750166072?pt=LH_DefaultDomain_0&hash=item4d023f0438) and whilst it would come in at £200 from the US it does have a working (but non-original) cone. in the uk it seems there are very few of these (?) in fact you can't even buy them from pioneer

regrding the aluminium, i think that would be the best thing because it is rigid and will not change any of the resonnance of the speaker. i was worried that just using rubber gasket would create a springy effect and change the qualities of the speaker.

i can get a friend to laser cut (so lazy!) some 6mm plywood rings to use as a slightly cheaper alternative maybe? could also put a bit of 1mm neoprene to make them airtight where they meet the baffle. don't want to fix them permanently. there won't be much difference between using ply and using aluminium though will there?

by the way, when you say you want a 1603 basket - are you going to recone it yourself or do you know someone who is competent, if so, where's the recone kit from? just interested if you can get em in the uk - every tech i speak to has not heard (of) them!
i still need to get 2 x 1603 reconed. i know someone who used to work for gauss that could maybe do it... but if you know of anyone... wouldn't mind trying myself but this is a bit of an expensive start point.

oh also: 1603 orig. diaphragms:
http://www.ebay.co.uk/itm/TAD-DP-1603-/190645342377?pt=LH_DefaultDomain_0&hash=item2c635910a9

thanks
tom

Yeah I saw that one ,but will wait for a basket . I have one sitting at Guido's waiting. I'l get Guido to recone them too ... He can get the kits . I looked at the Kits in the US ,but by the time I have landed them at G's front door they work out more expensive . I don't bother using anyone else for recones . I have used him since I started this insane hobby and see no reason to change - he's a perfectionist !
The plywood/ Laser treatment sounds good . I would use very good quality marine or birch ply though .
Where on this little island are you ?

Rich

[teddy.edwards1]

Yeah I saw that one ,but will wait for a basket . I have one sitting at Guido's waiting. I'l get Guido to recone them too ... He can get the kits . I looked at the Kits in the US ,but by the time I have landed them at G's front door they work out more expensive . I don't bother using anyone else for recones . I have used him since I started this insane hobby and see no reason to change - he's a perfectionist !
The plywood/ Laser treatment sounds good . I would use very good quality marine or birch ply though .
Where on this little island are you ?

Rich

I'm up in Leeds... where abouts in London are you?
Yeah I use birch ply in all my speaker builds, not marine though - that's crazy expensive now...
It might be nice to have a contact for this re-coner you use - the guy up here I go to is often away fixing tape machines and desks around the world, and even when he is here it's real hard to pin him down sometime. I come to London to see tech guys for some of my gear so it might be a possibility when i recone get round to using my 1603s. I have four 1601's ready to go and i kinda like the 421's for now in my monitors so it's not pressing.
What cabs will you be using the 1603's in? will they be mounted in front of the baffle?!
I think you advised me to go 4-way (not including sub) in my setup in a previous post. Unfortunately this is not an option as there is limited space and we need room for dancing!

Do you have any opinions on how thick this new gasket/ring should be - i'm looking at 7mm at the moment.

Tom

[richluvsound]

I know Leeds very well . I lived in Kirkstall ,by the Abby -spent 8 years up there playing semi-pro cricket ,doing a degree and working .
Now I live in Dulwich SE London .

My cabinet ..... ? no idea yet . Something bespoke anyway . I will be using the Radian / Truextent combo and the 1603 . Its a long term project.
Guido will design the networks for it . I'll stick to a 2-way . Unless I want to spend serious amounts of dosh I don't think I can improve on the basic 2-way . Besides, I have done the big 4-way thing ,but alas,I don't have the room any more .

Back on topic !

I guess your stuck with the original aperture ,which is 15" ? now you need to clear the surround for rear mounting as the TAD is 16" ? I would stick to the ply idea . I can't see any problem as long as you keep to the 7 mm minimum ! If the cone travels more than that ..... you have just blown the Woof .. LOL
Pics really help to visualise mate !

Guido is on here ,contact him via PM or http://www.behringer-electric.de/

We'll have a drink the next time your down my way !

Rich

[teddy.edwards1]

I know Leeds very well . I lived in Kirkstall ,by the Abby -spent 8 years up there playing semi-pro cricket ,doing a degree and working .
Now I live in Dulwich SE London .

My cabinet ..... ? no idea yet . Something bespoke anyway . I will be using the Radian / Truextent combo and the 1603 . Its a long term project.
Guido will design the networks for it . I'll stick to a 2-way . Unless I want to spend serious amounts of dosh I don't think I can improve on the basic 2-way . Besides, I have done the big 4-way thing ,but alas,I don't have the room any more .

Back on topic !

I guess your stuck with the original aperture ,which is 15" ? now you need to clear the surround for rear mounting as the TAD is 16" ? I would stick to the ply idea . I can't see any problem as long as you keep to the 7 mm minimum ! If the cone travels more than that ..... you have just blown the Woof .. LOL
Pics really help to visualise mate !

Guido is on here ,contact him via PM or http://www.behringer-electric.de/

We'll have a drink the next time your down my way !

Rich

Ha, yeah I live near where you lived...

Look (http://www.google.co.uk/imgres?imgurl=http://www.audioworld.com/wp-content/uploads/2011/02/altec.lansing.a7.oblique.gif&imgrefurl=http://www.audioworld.com/audio-production/pro-audio/2003/altec-lansing-legacy-a7-loudspeaker/&h=490&w=291&sz=36&tbnid=qa188ND73y_biM:&tbnh=90&tbnw=53&zoom=1&usg=__KzRWVIDOpvJtkL1MlZ2CGNcXLvQ=&docid=f2nmyLyFiJKstM&sa=X&ei=NQjiT_-sJYSf8gPR08nVDg&ved=0CFQQ9QEwAA&dur=846)at the A7 - the speaker is hidden partially behind the baffle.
The Xmax of the TADs is 8mm
The Xmax for the Altec is 0.12 inches or 3mm

So i feel I may be 1mm short - and i really REALLY don't want to damage these TAD drivers as they cost an arm and a leg.
So i could use 6mm ply with 1mm neoprene on each side = 8mm
or use 9mm ply with 1mm neoprene on the side meeting the baffle = 10mm

so boring, but so important.

tom

[teddy.edwards1]

now i look closer at the TAD spec i see something else:




Max. Excursion Before Damage (P-P) 36,0 mm

Which would mean the driver moves forward 18mm.
that is a lot.

on the altec 515-8ghp the same figure is 0.85 inches or 22mm
meaning 11mm fwd driver movement

Then i look again at the difference in gasket (the altec it 7mm more!)
it makes me think i should use 12mm ply! no more laser cutter.

tom