Dear Elias,
I tried to play with four amps.
And 300B single sounds with a sharp sound.
I think you don't have to worry about the damping factor.
Softone Model8-300B (300B single tube amp , 8W+8W)
Triode VP-300-BD(300B parallel-single amp , 20W+20W)
Nmode X-PM7 (1bit DSD digital amp , 18W+18W)
NuPrime STA-9 (A+D class digital amp , 120W+120W)
Led Zeppelin / Stairway to heaven
YouTube / TWTD-13.5T + MarkAudio MAOP10 + 300Bsingle(Softone Model8-300B)
真空管アンプ(300Bシングル)と13cmフルレンジ(MAOP10)で聴く～天国への階段/レッド・ツェッペリン - YouTube
YouTube / TWTD-13.5T + MarkAudio MAOP10 + A+D class digital amp(NuPrime STA-9)
デジタルアンプ(A+D級デジタル)と13cmフルレンジ(MAOP10)で聴く～天国への階段/レッド・ツェッペリン～真空管の魅力的な音調を目指したNuPrime STA-9の音や如何に!? - YouTube
I tried to play with four amps.
And 300B single sounds with a sharp sound.
I think you don't have to worry about the damping factor.
Softone Model8-300B (300B single tube amp , 8W+8W)
Triode VP-300-BD(300B parallel-single amp , 20W+20W)
Nmode X-PM7 (1bit DSD digital amp , 18W+18W)
NuPrime STA-9 (A+D class digital amp , 120W+120W)
Led Zeppelin / Stairway to heaven
YouTube / TWTD-13.5T + MarkAudio MAOP10 + 300Bsingle(Softone Model8-300B)
真空管アンプ(300Bシングル)と13cmフルレンジ(MAOP10)で聴く～天国への階段/レッド・ツェッペリン - YouTube
YouTube / TWTD-13.5T + MarkAudio MAOP10 + A+D class digital amp(NuPrime STA-9)
デジタルアンプ(A+D級デジタル)と13cmフルレンジ(MAOP10)で聴く～天国への階段/レッド・ツェッペリン～真空管の魅力的な音調を目指したNuPrime STA-9の音や如何に!? - YouTube
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STAIRWAY TO HEAVEN
Dear nandappe
early afternoon of a rather worm sunny day.
I'm listening right now as I'm typing.
Thanks for the answer. I'm avoiding valve amplifiers as well as digital ones. I will try your enclosure with my AB-class transistor amplifier for begin and I'm thinking. If I replace the port with a passive speaker what could happen ?
Elias
Dear nandappe
early afternoon of a rather worm sunny day.
I'm listening right now as I'm typing.
Thanks for the answer. I'm avoiding valve amplifiers as well as digital ones. I will try your enclosure with my AB-class transistor amplifier for begin and I'm thinking. If I replace the port with a passive speaker what could happen ?
Elias
Member
Joined 2009
Paid Member
Here is a first attempt at a concrete enclosure for Alpair 7p.
They turned out pretty much as good as I could have hoped for.
Aside from them making it out of the molds with no defects, I've briefly listened to one speaker, no stuffing and the front baffles are still in the process of being chipped back and smoothed down (which was a bad design choice, It should just have been incorporated into the mold.)
It sounded quite promising, no unpleasantness, a satisfying bass response from the port, and already it seems the round baffles will help the speaker to image better (i.e 'disappear').
I dont think the concrete mix turned out very strong, luckily it doesnt need to be, but I'm giving it at least couple weeks to cure before finishing them up.
And also the weight, I expected it to be a lot worse but they are perfectly manageable...
maybe a lot of air left in the mix?
A small hand sander was used to provide some vibration, it helped fill out the mold but probably didn't help much with air bubbles.
They turned out pretty much as good as I could have hoped for.
Aside from them making it out of the molds with no defects, I've briefly listened to one speaker, no stuffing and the front baffles are still in the process of being chipped back and smoothed down (which was a bad design choice, It should just have been incorporated into the mold.)
It sounded quite promising, no unpleasantness, a satisfying bass response from the port, and already it seems the round baffles will help the speaker to image better (i.e 'disappear').
I dont think the concrete mix turned out very strong, luckily it doesnt need to be, but I'm giving it at least couple weeks to cure before finishing them up.
And also the weight, I expected it to be a lot worse but they are perfectly manageable...
maybe a lot of air left in the mix?
A small hand sander was used to provide some vibration, it helped fill out the mold but probably didn't help much with air bubbles.
Attachments
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I have gathered a lot of stuff to make my own concrete speakers (Dayton Audio PS95) as a fun project.
I have to make the parts of the mold for the driver, slightly countersunk.
But a few questions:
Thickness of the walls?
Have you any reinforcement? I will add some finely ground granite and looking into using shredded fiberglass.
Did you incorporate screws or nuts in the cement to fasten the drivers?
I have to make the parts of the mold for the driver, slightly countersunk.
But a few questions:
Thickness of the walls?
Have you any reinforcement? I will add some finely ground granite and looking into using shredded fiberglass.
Did you incorporate screws or nuts in the cement to fasten the drivers?
Base is about 4cm, top is about 5cm, side walls have no constant thickness (varies 2.5cm to 5cm)
No reinforcement, just mixed small size aggregate, kept it cheap and simple. Of course there is so much potential for experimentation there.
Bolts are set into the concrete with nuts to fasten the driver. The wall is only ~1cm thick under the driver, Im nervous about the durability of this, hoping they wont just crack or crumble when they start to get some use.
No reinforcement, just mixed small size aggregate, kept it cheap and simple. Of course there is so much potential for experimentation there.
Bolts are set into the concrete with nuts to fasten the driver. The wall is only ~1cm thick under the driver, Im nervous about the durability of this, hoping they wont just crack or crumble when they start to get some use.
Listening/tweaking since yesterday and they sound decent, difficult to say if they are objectively good because I dont have much to compare to.
For sure a step up over the old sealed pine box+MDF baffle, cleaner decays and generally less haze.
There seems to be some slight upper mid ''peakiness'. This is somewhat familiar, the A7p always had some peakiness/weirdness in this upper mid area, it seems much narrower (good) but maybe stronger? It could well be a quality of a7p getting highlighted because of the improvements in the rest of band.
The first day I had ~1'' of polyfill lining that was reused stuffing from old sealed boxes, not very good lining material and I assumed this wasnt helping the peakiness.
That lining was replaced with a gym mat , sort of dense rubbery foam, ~10mm.
Only a slight improvement to peakiness, along with an overall more damped sound (less dynamic, but cleaner). Still xperimenting
Imaging is a lot better, much more realistic, though maybe the large flat baffles of the old sealed enclosure just had bad imaging.
Stereo imaging doesn't seem that great however, most likely because of not great channel matching due to inconsistent concrete mixes. I could be imagining it, the a7p is really sensitive to positioning.
For sure a step up over the old sealed pine box+MDF baffle, cleaner decays and generally less haze.
There seems to be some slight upper mid ''peakiness'. This is somewhat familiar, the A7p always had some peakiness/weirdness in this upper mid area, it seems much narrower (good) but maybe stronger? It could well be a quality of a7p getting highlighted because of the improvements in the rest of band.
The first day I had ~1'' of polyfill lining that was reused stuffing from old sealed boxes, not very good lining material and I assumed this wasnt helping the peakiness.
That lining was replaced with a gym mat , sort of dense rubbery foam, ~10mm.
Only a slight improvement to peakiness, along with an overall more damped sound (less dynamic, but cleaner). Still xperimenting
Imaging is a lot better, much more realistic, though maybe the large flat baffles of the old sealed enclosure just had bad imaging.
Stereo imaging doesn't seem that great however, most likely because of not great channel matching due to inconsistent concrete mixes. I could be imagining it, the a7p is really sensitive to positioning.
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It dawned on me that the light polyfill lining would have given slight increase to virtual volume, but the new rubbery mat lining would only steal volume.
I readded polyfill on top of mat lining and the most noticeable thing was further improvement to overall clarity, some of lost dynamics returned....
Not sure if or how this has anything to do with the potential change in volume,
the effects on stuffing mid-high frequencies is not really discussed a lot
even most of the discussion on bass is probably oversimplified.
it still sounds kind of compressed and it is starting to bother me, probably gonna remove the mat lining
I readded polyfill on top of mat lining and the most noticeable thing was further improvement to overall clarity, some of lost dynamics returned....
Not sure if or how this has anything to do with the potential change in volume,
the effects on stuffing mid-high frequencies is not really discussed a lot
even most of the discussion on bass is probably oversimplified.
it still sounds kind of compressed and it is starting to bother me, probably gonna remove the mat lining
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Hi Dave.
I have little to no reference regarding how it should sound as I haven't heard such speakers before. Comparing to my previous bookshelves which were sealed and based on a pair of re-intro version of the classic Hi-Q 8inch driver once built by Philips, these are many steps forward at once for me, both lookswise and soundwise.
The overall response is beautiful. Low-mid and above is smooth, with extended and pleasing highs (there is a slight port resonance at somewhere between 700Hz and 900Hz which I guess I will have to try to manage with stuffing inside the ports?). The response below 100Hz made me really happy, the bass is not above the rest, neither does it feel lost anywhere down to 40Hz (at 40-ish hertz there is a slight response peak). Note-to-note bass level in this 40-100Hz region is surprisingly well equalized! The bass seems to merge with the rest so well that although I planned to assist them with the subs you see in the pictures in my 2.2 active setup, I am actually liking them a lot playing by themselves without any bass assist - it's not as pronounced as my single round-ported speakers, but relaxed and enjoyable. Other than the port resonance mentioned above, the rest of the band is coming flawless to my ears.
I have little to no reference regarding how it should sound as I haven't heard such speakers before. Comparing to my previous bookshelves which were sealed and based on a pair of re-intro version of the classic Hi-Q 8inch driver once built by Philips, these are many steps forward at once for me, both lookswise and soundwise.
The overall response is beautiful. Low-mid and above is smooth, with extended and pleasing highs (there is a slight port resonance at somewhere between 700Hz and 900Hz which I guess I will have to try to manage with stuffing inside the ports?). The response below 100Hz made me really happy, the bass is not above the rest, neither does it feel lost anywhere down to 40Hz (at 40-ish hertz there is a slight response peak). Note-to-note bass level in this 40-100Hz region is surprisingly well equalized! The bass seems to merge with the rest so well that although I planned to assist them with the subs you see in the pictures in my 2.2 active setup, I am actually liking them a lot playing by themselves without any bass assist - it's not as pronounced as my single round-ported speakers, but relaxed and enjoyable. Other than the port resonance mentioned above, the rest of the band is coming flawless to my ears.
... A follow up.
The drivers' sound quality is jaw-dropping, but so is the midrange SHOUT (pretty common for this type of drivers it seems). I made an active equalization network that took away the shout but its bass level is a bit dependent on the impedance of the next stage which I don't like. Time for large iron laminate inductors!
The drivers' sound quality is jaw-dropping, but so is the midrange SHOUT (pretty common for this type of drivers it seems). I made an active equalization network that took away the shout but its bass level is a bit dependent on the impedance of the next stage which I don't like. Time for large iron laminate inductors!
How long have your a12p been broken in so far?
I thought my a7p was fully broken at this stage but after letting the play continuously for the past for few days they continue to improve.
Dave and a couple others were quoted as saying they'll continually improve into multiple hundred hours, I didn't believe it till now.
I thought my a7p was fully broken at this stage but after letting the play continuously for the past for few days they continue to improve.
Dave and a couple others were quoted as saying they'll continually improve into multiple hundred hours, I didn't believe it till now.