Probably SOL - 604D

I had been casting about for an upgrade for my Empire 208/MX110/MC240 system. Right now that system is driving a pair of Klipsch Heresy IIs. Which admittedly do like the tubes.

I began to home in on a pair of 604Ds as a likely perfect match. However! There?s always a however. I just don?t think I have the space for them. This system is in my home office which is about 12x12 and the area where my system is would only support about 7.5 cu feet for each speaker. Short of the recommended 9.

So, as an alternative I started looking the 12? vintage Altecs. But they don?t seem to get much love. I?m not sure they would be all that much of an upgrade on the Heresy IIs.

Any advice, thoughts, good news, bad news?

Hmm, a little larger than the ~10x12 I'm typing in and back when it had a Radio Shack DIY two way horn/'prosound' 15" woofer speaker system it was too much vented, but plugged up and against a wall was pretty good in ~5 ft^3, but the woofer had a low 20s Fs, higher Vas, Qts, than the 604, so wound up packing the vent with drinking straws [some just 'stick a sock' in it] and fine tune it using the 'click' test: Click test: Click Test | GM210 | Flickr

So; make it as big as you can, then tune to actual Fs [when it's pretty much stationary and all output is from the vent] and if it's 'boomy', fine tune with the 'click' test or impulse response if you're set up for measurements/testing.

GM

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Originally Posted by GM

Hmm, a little larger than the ~10x12 I'm typing in and back when it had a Radio Shack DIY two way horn/'prosound' 15" woofer speaker system it was too much vented, but plugged up and against a wall was pretty good in ~5 ft^3, but the woofer had a low 20s Fs, higher Vas, Qts, than the 604, so wound up packing the vent with drinking straws [some just 'stick a sock' in it] and fine tune it using the 'click' test: Click test: Click Test | GM210 | Flickr

So; make it as big as you can, then tune to actual Fs [when it's pretty much stationary and all output is from the vent] and if it's 'boomy', fine tune with the 'click' test or impulse response if you're set up for measurements/testing.

GM

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So, that's a no on the 412 or 601A? Because a 609 cabinet would be a good fit for the room. I considered 12" Tannoy Golds which would fit that cabinet nicely too. Also considered the AR3a, but if I got those they would probably be better suited the Marantz 2235/Marantz 250 setup.

If I do go 604D, the cabinet I build would probably be somewhere between a 612 and 614 utility cabinet. And then, like you say, try to get it tuned in to fit the room. I have a Mcintosh MQ101 but not sure the 604D could handle it.

Well, IME the bicones are so-so with a small baffle mounted tweeter and fine if there's an 811 horn combo to go with it and the 601A has a horn with a very delicate microphone diaphragm that's long time now irreplaceable, so your call.

Curious, is there room to go taller?

GM

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Originally Posted by GM

Curious, is there room to go taller?

GM

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Oh, plenty of room to go taller. 48" would be in reach

OK, great! What's your WxD max outside [o.d.] dims and seated ear height or at whatever height from the floor you will listen most? Is there anything limiting this size/shape WRT building/moving into place, i.e. doorways, stairs, relatively heavy weight?

GM

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Originally Posted by GM

OK, great! What's your WxD max outside [o.d.] dims and seated ear height or at whatever height from the floor you will listen most? Is there anything limiting this size/shape WRT building/moving into place, i.e. doorways, stairs, relatively heavy weight?

GM

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Right now I have Lane record cabinet with the amp on top in the middle of the space. In that configuration I could max out at around 17" wide and 15" deep. If that goes and I just put the amp on a platform I'd have an max around 20" wide and 16 deep.

I also noticed a cheap single 602a came up locally. I may make a low offer and make it into a mono speaker to play around with on the basement tube system. Think that would be fun.

OK, need a little side wall 'breathing' room, so 18.5" W x 13.5" D x 46.5" H [i.d.] = ~6.72 ft^3 - ~0.33 [604] + a little bracing puts it ~ the prosound/studio monitor preferred 612's 6 ft^3 net, not the optimal ~9 ft^3, but big enough tune to 35-40 Hz [most common tuning] if against a wall and even to Fs if there's enough room gain with any windows, doors closed. https://ci5.googleusercontent.com/pr...ilies/wink.png

Still need to know the preferred ear height for driver location and forgot to ask what amp will be used.

Presume there's no other considerations..........

GM

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Originally Posted by GM

OK, need a little side wall 'breathing' room, so 18.5" W x 13.5" D x 46.5" H [i.d.] = ~6.72 ft^3 - ~0.33 [604] + a little bracing puts it ~ the prosound/studio monitor preferred 612's 6 ft^3 net, not the optimal ~9 ft^3, but big enough tune to 35-40 Hz [most common tuning] if against a wall and even to Fs if there's enough room gain with any windows, doors closed. https://www.hostboard.com/forums/hbm.../2020/11/1.png

Still need to know the preferred ear height for driver location and forgot to ask what amp will be used.

Presume there's no other considerations..........

GM

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Now we're getting somewhere! The measurements I gave would include a good bit of space on the outsides.. Facing them on the right is a doorway and on the left is a door (to the sunroom) that opens toward the system. But, that's good, I'd rather not max the space.

This being my office system, I'm sitting pretty upright in an office chair. So, right around 45-47 inches. Amp is an MC240.

I meant, inside the cab ;) At 18.5" for a 15", it's a bit tight, so will need some damping stuck in gaps. OK, then at 48" won't be able to get the ears on axis with the driver at 36.75" [i.d.] from the baffle bottom/37.5" [o.d.] floor, but lucky you have an amp the driver was made for, so will boost the horn's extreme HF a bit, making it maybe OK off axis; otherwise may need a bypass cap to 'let through' extreme highs and worst case you have to add a proper CD horn EQ filter to it.

Vent specs, etc., later, it's nearly 2 am after a very long day rearranging leaves, so tech wise, going pretty much brain dead.

GM

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Originally Posted by GM

I meant, inside the cab ;) At 18.5" for a 15", it's a bit tight, so will need some damping stuck in gaps. OK, then at 48" won't be able to get the ears on axis with the driver at 36.75" [i.d.] from the baffle bottom/37.5" [o.d.] floor, but lucky you have an amp the driver was made for, so will boost the horn's extreme HF a bit, making it maybe OK off axis; otherwise may need a bypass cap to 'let through' extreme highs and worst case you have to add a proper CD horn EQ filter to it.

Vent specs, etc., later, it's nearly 2 am after a very long day rearranging leaves, so tech wise, going pretty much brain dead.

GM

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Right on. I was reading and responding at the same hour so missed the implication. I can't use leaves as an excuse, though. I've been studiously ignoring my 2.5 acres in hopes that the wind will do most of the work.

The amp is pretty much exactly why I ended up deciding on the Altecs. I was also considering going with JBL 130As or Tannoy 12" Golds. I wanted get something relatively time correct.

Do you think the 604d is capable of handling a Mcintosh MQ 101? I've got one sitting around looking pretty with no work to do. It could make up up for some of the size and setup constraints. But the warnings about it are always in the back of my mind.

Also, for the most part this system is for listening pleasure while I am working or sitting in my office reading or doing something else. So, perfection isn't a real goal for these. Just pleasurable listening.

The 8B and Quad ESL 57s in the basement listening room are where I really get down to sit and just listen. Although with a 5 year old the time for that is limited. Usually if he's down there with me, our choice of music is The Beach Boys Surf's Up. Long Promised Road (i.e. The Down Song) is his favorite. Or Roxy Music Flesh and Blood for Oh Yeah. Or something that is in blue vinyl because blue is his favorite color. Or anything that has a cover that looks cool.

Sweet! Mine calcs as ~1.34 acres with [8] huge trees, one with [4] full size trunks, one with [3] and two with [2], two <20 ft but seriously 'bushy' and a bunch of < 8 fters I keep stunted for privacy and a few < 4 fters for cheap decoration. This year is first time there wasn't enough roof, back or front yard area to sunbathe except down near the streets [corner lot] :(.


My knowledge of the MQ101 is from an RSVP audition a bit before its release IIRC and for whatever reason the tekkie told me it wouldn't work properly on my horn system without some $modding$ even though I had an all Mac separates tube system at the time, so circa '70-71. Best to ask McIntosh.


Vent = 4" dia. x ~0.75" [baffle thickness] centered up 7" from the bottom [i.d.].


GM

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Originally Posted by GM

Sweet! Mine calcs as ~1.34 acres with [8] huge trees, one with [4] full size trunks, one with [3] and two with [2], two <20 ft but seriously 'bushy' and a bunch of < 8 fters I keep stunted for privacy and a few < 4 fters for cheap decoration. This year is first time there wasn't enough roof, back or front yard area to sunbathe except down near the streets [corner lot] :(.


My knowledge of the MQ101 is from an RSVP audition a bit before its release IIRC and for whatever reason the tekkie told me it wouldn't work properly on my horn system without some $modding$ even though I had an all Mac separates tube system at the time, so circa '70-71. Best to ask McIntosh.


Vent = 4" dia. x ~0.75" [baffle thickness] centered up 7" from the bottom [i.d.].


GM

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Fantastic! Now all I have to do is rebuild my Empire 208, get my MX110 repaired (short burned out the tranny, bought it on the cheap that way), bring the MC240 up on the variac and build cabinets. Nothing to it!

My town has a saying: ?too many damn trees?. I live close to Boston but you?d not know it, we?re a very rural seeming town on the surface.

Ill try the speakers for a while and see how I feel about the bass and decide if something needs to be done. Just picked up my pair. Found on Facespace marketplace about an hour from me.

I didn?t realize they were in a pair of cabinets. Homemade. The guy I got them from got them from an old-timer. Shortwave enthusiast who built the cabinets and a pair of crossovers for them. He did also give me the N-1600-B crossovers that were also in the cabinets when he picked them up. Both marked N-1600-B but different sizes?

The cabinets are 5.6 cu ft. I?ll just use them for now since I didn?t expect to build cabinets for a couple of months, likely.

Ok. So, I have a set of legs coming (nice tapered oak ones with brass caps, it'll look very midcentury modern with 11 degree mounting plates) but for the moment I have them set up in my office with a Micro Seiki DD40, Marantz 2235 and Marantz 8b. I have them on boxed so only raised up an extra 9" or so. The cabinets are 28" tall, 18 1/4" deep and 24" wide. And they sound amazing. I've got a mono first press of Pet Sounds on now and I am not pining for any missing bass. I think I've found a pair of keepers. I can't see ever moving on from this sound. Unless something like a pair of 755a speakers should fall into my lap, of course!