Ok, let's go with the idea of a separate chamber for the 604 and 416 as used in the 6041 reference from GM. Given that I am going to drive the 416 with a plate amp, can I come up with a total combined enclosure volume around 9 cf, maybe spilt 40/60, allowing that the 604 will roll off pretty early, and using the low z and eq of the plate amp to make the 416 live in a way smaller than optimal enclosure?
Greets!
Dunno, first we need to know the worst case tube amp output impedance for the 604 as this affects its minimum Vb, which will need to be either sealed or aperiodic to keep it as small as practical to give the 416 enough Vb to 'breathe'.
BTW, did I miss it or have you yet to tell us which 416 you have and is it original (some have radially different specs depending on the app it was intended for) or a non-factory re-cone? (if the latter, then without measured specs it's a crapshoot as to how accurately it will perform WRT the sim.
Anyway, at a glance I'm thinking an aperiodic ~1 ft^3 gross for the 604, which theoretically allows a ~150 Hz/2nd order XO to keep the drivers within 1/4 WL and minimizes the effect of using different output impedance amps, leaving ~8 ft^3 gross for the 416 which allows as low as a ~Fs tuning if need be without an excessive vent length.
GM
Dunno, first we need to know the worst case tube amp output impedance for the 604 as this affects its minimum Vb, which will need to be either sealed or aperiodic to keep it as small as practical to give the 416 enough Vb to 'breathe'.
BTW, did I miss it or have you yet to tell us which 416 you have and is it original (some have radially different specs depending on the app it was intended for) or a non-factory re-cone? (if the latter, then without measured specs it's a crapshoot as to how accurately it will perform WRT the sim.
Anyway, at a glance I'm thinking an aperiodic ~1 ft^3 gross for the 604, which theoretically allows a ~150 Hz/2nd order XO to keep the drivers within 1/4 WL and minimizes the effect of using different output impedance amps, leaving ~8 ft^3 gross for the 416 which allows as low as a ~Fs tuning if need be without an excessive vent length.
GM
Thanks GM for the effort you are putting into this! My 416s are B models, 8 ohm, mid 80 vintage, and original. I will try to arrive at a output impedance for the amps that will drive the 604. They are pp tube, no feedback, so a fairly high zout. I guess a question that needs to be asked is am I making something overly complex - that is, will the 416/604 combo be worth the extra effort as compared to the 604 in the large box? The 416's can continue their existance in the small box/plate amp combo if this is a better or more practical solution.
jim
jim
Jim,
I looked into getting a pair of these new from GPA as part of an OB setup. I modelled them in all sorts of boxes, and to my mind, the best solution was the 604 crossed somewhere around 150Hz to a dedicated bass assembly.
Given what you have, if it were me, I'd configure it with the 604 in an aperiodic box or possibly OB, and the 406 optimised in it's own enclosure and x-ed over below the 604. The O/P Z of your tube amp will only help in the OB/aperiodic but it may need the xover values recalced out from the GPA/Markwart designs. May not too. I use EL38 trioded PP designs which have an O/P Z of about 3R.
An aperiodic could still be included in the same cabinet as the 406, just with isolated volumes.
Just summat to consider.
I looked into getting a pair of these new from GPA as part of an OB setup. I modelled them in all sorts of boxes, and to my mind, the best solution was the 604 crossed somewhere around 150Hz to a dedicated bass assembly.
Given what you have, if it were me, I'd configure it with the 604 in an aperiodic box or possibly OB, and the 406 optimised in it's own enclosure and x-ed over below the 604. The O/P Z of your tube amp will only help in the OB/aperiodic but it may need the xover values recalced out from the GPA/Markwart designs. May not too. I use EL38 trioded PP designs which have an O/P Z of about 3R.
An aperiodic could still be included in the same cabinet as the 406, just with isolated volumes.
Just summat to consider.
JimW said:
We're very lucky to have him.
The versatility of having a second woofer with it's own amp will be big plus over the 604 alone.
My only thought on that is that Altec woofers do such a good job when crossed over higher that you might be missing a little of the magic by using a plate amp on the 416. OTOH you are using the 604 for vocals so if that luxury is available...hmmm. Nice to have your conundrum.
Greets!
You're welcome!
OK, then for best performance we need all the cab Vb we can muster for the 416.
Don't have a clue, I'm not you. Driven with a high output impedance amp, the 604 in a big, low tuned cab can be audio nirvana for some, but if you want to 'get real' with all that digital has to offer you'll probably wind up wanting not one, but two 416s in huge cabs to fill in the bottom end.
Really, as Cal implied, either option is a waste of 416's as we want to keep the XO as low as practical without over excursing it.
GM
You're welcome!
OK, then for best performance we need all the cab Vb we can muster for the 416.
Don't have a clue, I'm not you. Driven with a high output impedance amp, the 604 in a big, low tuned cab can be audio nirvana for some, but if you want to 'get real' with all that digital has to offer you'll probably wind up wanting not one, but two 416s in huge cabs to fill in the bottom end.
Really, as Cal implied, either option is a waste of 416's as we want to keep the XO as low as practical without over excursing it.
GM
Update
Hi GM, hope all is well.
The GPA 604's have been living happily on JE labs open baffles. I wanted to see how they sounded before I built cabs, so I threw together a pair of these large baffles, and am not sure if I will put them in a box. I have a couple of remodeling projects going, and the WAF would be quite low for me to undertake any cabinet building at this time, although I am not ruling it out after the projects are finished. I did listen to them for a while in some boxes (totally not optimized for the driver) to see if the box coloration was as apparent as others have maintained, and it was, so I have developed a predisposition for the open baffle sound! Knowing these are very low q drivers I full well expected them to be bass shy, and they are, on the JE labs baffle f3 at listening position is right at 75 hz. I am supplimenting them with a pair of dayton 10" subs, the combination works well, giving a failry flat response at listening position with f3 of 35 hz. An idea I have floating around in my mind is to go to a taller, narrow baffle, possibly u shaped to get the 604 horn to ear level, although the driver being near the floor on the JEL baffle hasn't resulted in a low sound stage, rather the width of the baffle makes placement in the room a bit more of a challenge. If I went to the taller baffle, I could possibly use the 416 I have to function as a .5 way to make up for the narrow baffle. I would still expect a fairly high f3 and require the subs. I was actually planning to add two more of the dayton subs (total of four), as they seem to integrate very well with the 604's, but I wonder about the ability of these two small subs to keep up with the GPA's at louder levels.
I will say the 604's are the finest speaker I have had the pleasure of owning!
As always, I read anything you post, I have found you to be a wealth of information and am thankful you take the time to share your knowledge.
Jim Womble
Hi GM, hope all is well.
The GPA 604's have been living happily on JE labs open baffles. I wanted to see how they sounded before I built cabs, so I threw together a pair of these large baffles, and am not sure if I will put them in a box. I have a couple of remodeling projects going, and the WAF would be quite low for me to undertake any cabinet building at this time, although I am not ruling it out after the projects are finished. I did listen to them for a while in some boxes (totally not optimized for the driver) to see if the box coloration was as apparent as others have maintained, and it was, so I have developed a predisposition for the open baffle sound! Knowing these are very low q drivers I full well expected them to be bass shy, and they are, on the JE labs baffle f3 at listening position is right at 75 hz. I am supplimenting them with a pair of dayton 10" subs, the combination works well, giving a failry flat response at listening position with f3 of 35 hz. An idea I have floating around in my mind is to go to a taller, narrow baffle, possibly u shaped to get the 604 horn to ear level, although the driver being near the floor on the JEL baffle hasn't resulted in a low sound stage, rather the width of the baffle makes placement in the room a bit more of a challenge. If I went to the taller baffle, I could possibly use the 416 I have to function as a .5 way to make up for the narrow baffle. I would still expect a fairly high f3 and require the subs. I was actually planning to add two more of the dayton subs (total of four), as they seem to integrate very well with the 604's, but I wonder about the ability of these two small subs to keep up with the GPA's at louder levels.
I will say the 604's are the finest speaker I have had the pleasure of owning!
As always, I read anything you post, I have found you to be a wealth of information and am thankful you take the time to share your knowledge.
Jim Womble
Greets!
Same old 'aces n' eights'!
You're welcome!
Yeah, there's a relaxed, natural sound to OBs that is hard to beat short of an all horn loaded system, which requires so much room that it's not an option for most folks. Acoustically large enough MLTLs or ML-horns can come close though in that they perform ~like IBs except with some added gain.
Still, BW limiting the 604s on an OB to around 80-100 Hz and filling the bottom end with enough woofer power is a tough act to follow, though a narrow baffle will of course raise its F3 even if U shaped which increases the potential to botching the XO as you move up into our acute hearing BW, plus if deep enough to shroud the driver you'll have to deal with cavity resonances.
WRT subs, I fall into the 'more is better' group WRT sub count and if you have enough of them they don't have to be all that big as long as they sum well enough to get the desired low distortion peak SPL the app requires.
GM
Same old 'aces n' eights'!
You're welcome!
Yeah, there's a relaxed, natural sound to OBs that is hard to beat short of an all horn loaded system, which requires so much room that it's not an option for most folks. Acoustically large enough MLTLs or ML-horns can come close though in that they perform ~like IBs except with some added gain.
Still, BW limiting the 604s on an OB to around 80-100 Hz and filling the bottom end with enough woofer power is a tough act to follow, though a narrow baffle will of course raise its F3 even if U shaped which increases the potential to botching the XO as you move up into our acute hearing BW, plus if deep enough to shroud the driver you'll have to deal with cavity resonances.
WRT subs, I fall into the 'more is better' group WRT sub count and if you have enough of them they don't have to be all that big as long as they sum well enough to get the desired low distortion peak SPL the app requires.
GM
Take my observations with a grain of salt as I don't have any good way to measure. My room is somewhat live, and I believe this would have effect on my observations. I listen a lot in an off axis position (I have a computer at the edge of the room, a lot of times I'll play records and surf the net). While the imaging would obviously suffer, the overall tonal balance remains very good. I listen with the speakers toed-in about 15 degrees (swag), so when I am sitting in center listening position, I am listening slightly off axis. The toe-in gives me the best imaging in my room. I am using the stock GPA crossovers, many have reported the Markwart crossover to be an improvement, especially offering level control for the horn.
Jim
Jim
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