Yes, LF is at full range. I have made thick felt acoustical damping blocks the to the middle section of LF cone (around the horn) to reduce lower level overlap frequencies above 1.6khz. My new 604C´s LF frequency response is smoother and goes quite nicely down from 1.6khz and need only little damping, but my earlier 604E`s needed heavy damping due to LF 2khz peak.
Russian paper diaphrams for Altec horns
- Thread starter Aptone
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MissionX
Keep it Silky
Nice crossovers. What did you do about the stepped inductor? I can't tell from the pictures. I have N1500 and Mastering Labs and can't really tell the difference on a short listening session with my 605Bs. I should probably revisit that. It's not like the dramatic difference between a N500 and Hiraga as are on my A5s.
cccrchairman
New Member
I am looking to get in touch with Alex for another pair of 288 diaphragms. I currently have a pair of the 'copper-lite'. I would like to compare with aluminium coil. Appreciate any help in this regard and as this is my first post here hello to all.
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Acoustical damping is made outside of the speaker cone as you can see in the pictures. The 604E´s needed damping four sides to get tolerable with 2khz peak. 604C needed only one block above the horn to get crossover region flat enough with original HF aluminum diaphgram. The 5-8khz +3db peak problem remained, which I could remove acoustically with little felt blocks located inside of three outer cells of the horn. Now they sound pretty impessing. I just ordered paper diaphgrams from Alex with copper voice coils. 6 weeks to wait to Finland due to war restrictions.
MissionX
Keep it Silky
Welcome to the forum. I sent you a PM. I could post his email on the forum if it's doesn't break any rules. Tell us your impressions of the aluminum when you get them. Don't be a stranger, this is important stuff here.
Yes, they work right also with higher volumes witout loosing rockn roll. Here are pictures at 80db at listening position with 1db scale and 3db scale with pink noise.
The sub amps are out with this measurement. With them (2x15" Altec 515) the frequency response goes about flat to 20hz
I unwound a 1.5mH coil, till it reached 1.35 and tapped it there, I thought winding back the coil would yield the .15mH from the point I tapped to the end, however it didn't, it measured clost to 0 only, may be due to the manual winding which wasn't as tight as it was supposed to be. So, I had to use another .15mH coil in series from the 1.35 tap.
I have a 605b pair too and your observation about the XO effect on them resonates mine, they sounded a little more smooth with Markwarts compared to N1600C, and at times I found N1600C series XO to be more lively and dynamic.
However 604's are very different and It took me a lot of time to tame them, and ML XO fixed everything which was concerning me, leading me to towards going back to 605's
The ML XO design is very clever in terms of addressing the peaks, from both woofer and compression drivers. Only thing is I had to add a pre before my 45 SET amp for the comfertable gain.
Regards
sann
I am civil engineer from training and studied also little acoustics to get familiar with the sience of sound. Last 23 years musician, teaching guitars, bass, slide, band playing and recording in my all analog home studio. Self taught in electronics, building, modifying and maintaining tube amps, mic pres, speakers and all studio equipment, still learning...
The design of the room acoustics was trouble, like allways in our little (under 100 m2)listening rooms. To tame standing waves had to make absorbing walls and roof. Side walls about 0.5m heavy wool per side (compromise due to narrow room) , front/back wall and roof (after wool) to open air in attic. Getting away with speaker first reflections had little trouble too, as you can see also in the picture. Reflective/dispersing surfaces in back....
With Altec 604´s I tried to utilize corner disposition to get acoustical help (+9db ) to bass region. With 3.5m transmission line cabinet couldnt get the bass powerful enough due to phase problems in low bass. Closed the line end and took 2x15" Altecs (515 hollywood and 416 until I find another 515 hollywood) for help in 20-80hz region, wasnt easy task, still in progress, but now it rocks, thank God!
Sann, about taming glare of 604´s. some observations, I have learned.
In binding posts the signal goes through magnetic screw in LF posts, awful. I made new copper plate screw terminals. I have found, that all copper path in connections is way to go from voicecoil to amp to avoid unpleasant/unmusical artifacts (low level distortion). Also copper alloys like brass glares like grazy. We dont need extra batteries (potential difference between materials) in the audio signal path.
Removing back plate/end cup (3 screws) removed glare also. Connecting directly to Voicecoil screw terminals helps.
Removed dope of 604C´s also, to get more cone flexibility/dynamics
The room acoustics is in important with good dynamic speakers like 604. With speakers alone we tinker with few db problems, but with room acoustics x10 of that, and that easely leads to wrong decicions (less dynamic) in component and design choices as we try to compensate the bad room acoustics.
In binding posts the signal goes through magnetic screw in LF posts, awful. I made new copper plate screw terminals. I have found, that all copper path in connections is way to go from voicecoil to amp to avoid unpleasant/unmusical artifacts (low level distortion). Also copper alloys like brass glares like grazy. We dont need extra batteries (potential difference between materials) in the audio signal path.
Removing back plate/end cup (3 screws) removed glare also. Connecting directly to Voicecoil screw terminals helps.
Removed dope of 604C´s also, to get more cone flexibility/dynamics
The room acoustics is in important with good dynamic speakers like 604. With speakers alone we tinker with few db problems, but with room acoustics x10 of that, and that easely leads to wrong decicions (less dynamic) in component and design choices as we try to compensate the bad room acoustics.
MissionX
Keep it Silky
IME, the 416 has more LF extension than a 515 or 515B. Like when I install a 416 in my A5 cabinets. This is not true in your experience?
It is true also in my experience, thank you for asking. 416 gives more powerful/dynamic sound and blends better in my system. Also spectrum analyzer frequency response curve with pink noise looked quite flat at 25-80hz for 416. 515 begins to dip from 40 hz as you can see in the pictures attached.
I had not marked the speakerwires of 515 and 416 and allways supposed wrongly that it was 515 sounding deeper. At weekend I had time to get the cones visible, which were in the back of acoustical damping pad. Thank you MissionX !!! Now I will be searching for another 416, which will be hopefully easier and not so costy.
Here are curves at 1db/step, first is 515. The back of the cabinet is open to free air at attic, there is 30cm wool (thermal insulation of wall ) between
and 416 below
MissionX
Keep it Silky
You're welcome. You should have no problem finding an original 416! They are "relatively" cheap compared to an original 515. There's a couple on eBay right now. Now the pleated surround would allow a 515B to go a little deeper, right, but not as deep as a 416? You have a Hollywood, so it has a paper hinge? If I remember correctly, @GordonW told me the smaller magnet allows the 416 to have more low frequency extension than the 515B. My memory is not that great, though. I think the 416s blend a little better as well. You don't really need a sub with them in most instances with the music I listen to. Not always, Now when I put my 515s back in, I will say they are better.
Yes, the 416, due to lower magnetic flux, has a higher Q than the 515. The rest of the specs (compliance, cone mass, etc) are almost identical. This gives the 515 a higher broadband efficiency and more HF extension (due to the stronger motor- it can accelerate the cone faster), at the expense of low end extension, just a bit.
The stronger motor also puts the 515 in a parameter range, where they work better in bass horns than the 416. The horn can make up for the loss of LF extension, in many cases.
Regards,
Gordon.
The stronger motor also puts the 515 in a parameter range, where they work better in bass horns than the 416. The horn can make up for the loss of LF extension, in many cases.
Regards,
Gordon.
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