MarkAudio Alpair 12P seems to be a perfect full range.
Have you any thoughts or experience of this driver?
Have you any thoughts or experience of this driver?
Not perfect, but a very nice driver. I've lived with a pair in Super Pensil enclosures for over 10 years now (time flies). A little forward at times in the midrange, but overall pretty good with most music genres. Good bass extension, but this isn't a small box. Will play loud in an average size room with 5 watts if that matters.
jeff
jeff
I have a pair too in superpensil and can confirm with the observations of vinylkid58. I like the bass and the vocal especially .
It works well with the simple class d amp. The high frequency is adequate for triangles and lack the air for the high hat when compared to dedicate tweeter. Piano notes are distinct and very pleasant .
It works well with the simple class d amp. The high frequency is adequate for triangles and lack the air for the high hat when compared to dedicate tweeter. Piano notes are distinct and very pleasant .
12P is terrible driver, unpleasant, fatiqueing, not good bass not good highs.. maop 10 is for the moment the best FR driver to my ears
I’ve got much fonder memories of my listening impressions to them in Jeff’s SuperPensils than a small standmount size MarKen style enclosure of Dave’s design; but that was a fair while ago.
The Alpair 12 is not an ideal driver. I built Super Pencil cabinets with this drivers and I am disappointed. The speakers are very demanding in terms of amplifier requirements, sounds better with tube amp. For me, they sound too analytical, lacking warmth, and have a dry sound. After an hour of listening, I have a headache. Not my cup of tea.
The 12P is a borderline low-Q driver with a high conversion efficiency for its impedance / linear coil travel & was more or less created with an eye to high efficiency loads like the pensils or horns and higher output impedance amplifiers; although you can get decent results in smaller boxes and / or low output impedance amplifiers, the price is usable LF extension & a well-damped response unless external adaptations are applied, either via amplifier output impedance, series R or other EQ. So taking the overall response trending, it will generally (some exceptions) sound better-balanced in larger acoustically efficient enclosures & preferably with a well-matched amplifier design / equivalent compensation although an LS3/5a style alignment can work well in a modest box size -in its case through some form of vented loading rather than sealed though.
For the above, there are a few things you can do to improve things -remembering that the pensils are specifically designed to be user-adjustable so builders can adapt them as far as possible to their requirements:
For the above, there are a few things you can do to improve things -remembering that the pensils are specifically designed to be user-adjustable so builders can adapt them as far as possible to their requirements:
- Ensure the damping material is not in immediate proximity with the cone to prevent the air-mass loading the moving components excessively
- Reduce the overall damping density or that in proximity to the vent
- Insert a 1ohm - 2.2ohm power-resistor or series / parallel resistor array to the required power-handling level of equivalent value in series with the driver to ~mimic the effect of a higher amplifier output impedance. An alternative would be to replace the speaker leads with resistance wire / equivalent thereof of the desired loop-resistance for similar results.
Compared the MA 12P to MA 11MS , the 11 MS has more high freq information. I use class D, class A , class AB chip amps for 12P and I do not notice high frequency irritation. The amount of damping material in the superpensil box has a tremendous amount of effect on sound .
time to weigh in.
Cavest: I have not heard many of the new drivers — CHR/CHP-90/120, MA200, CHR/CHP-50. And MY opionions.
I will ignore CHN-70, P7PHD, and A7p. The first 2 are voiced weird, the latter lots of resonance issues.
1/MA Paper cones have a distinct voicing. The paper cone drivers have a vintage/quite controlled top end, whereas the metal tend to suffer from some HF ringing issues, which may or may not drive you nuts.
A12p can be very good. Most dynamic and most sensitive. A10p is not far behind sensitivity wize (-1dB) but hs greater DDR, particularily in the midrange. It is also a bit more bass capable. A6p is smaller, less bottom, better top. A12pw gives up sensitivity and a bit at the top to the A12p, but can go considerably lower and has better midband DDR.
The CHP-90 is supposed to be a decendent of the A10p.
WRT A11ms, it has some HF ringing which i find distracting, mostly ameriolated with application of a couple koats of thinned acrylic gloss.
MAOP treatment helps control the top end, decrease midband colouration, and increase DDR.
All the paper cones, IME, can be improved with a coat of puzzlekoat.
Of course, box implementation, room, support kits all play a significant role.
dave
Cavest: I have not heard many of the new drivers — CHR/CHP-90/120, MA200, CHR/CHP-50. And MY opionions.
I will ignore CHN-70, P7PHD, and A7p. The first 2 are voiced weird, the latter lots of resonance issues.
1/MA Paper cones have a distinct voicing. The paper cone drivers have a vintage/quite controlled top end, whereas the metal tend to suffer from some HF ringing issues, which may or may not drive you nuts.
A12p can be very good. Most dynamic and most sensitive. A10p is not far behind sensitivity wize (-1dB) but hs greater DDR, particularily in the midrange. It is also a bit more bass capable. A6p is smaller, less bottom, better top. A12pw gives up sensitivity and a bit at the top to the A12p, but can go considerably lower and has better midband DDR.
The CHP-90 is supposed to be a decendent of the A10p.
WRT A11ms, it has some HF ringing which i find distracting, mostly ameriolated with application of a couple koats of thinned acrylic gloss.
MAOP treatment helps control the top end, decrease midband colouration, and increase DDR.
All the paper cones, IME, can be improved with a coat of puzzlekoat.
Of course, box implementation, room, support kits all play a significant role.
dave
Looking back, I really liked the CHP-90 when I had it. ~14 L boxes, sealed. Very civilised and natural sounding. Bass was very well controlled and easily adjustable by pulling them further out into the room (thinner), or back into a corner (boosted).
The sound was far more full-bodied than my CHN-50's, but those are somewhat tighter and more crisp at high frequencies.
Extrapolating, I have high expectations for warm, jazzy bass from the 12P. And that's really the backbone. Getting the most out of the highs is probably the usual game with matching the speaker with a suitable amplifier (single digit damping factor, etc.)
300 Hz and up --> climbing impedance. Of course it looks a bit flattened, suggesting that the voice coil is loaded down by eddy currents in the surrounding metal (akin to secondary transformer windings, but with a small air gap). This reduces a particular type of modulation, where bass excursion modulates the physical position of the coil relative to the iron magnet poles, which in turn causes the impedance to get modulated away from the nominal values.
With Ohm's Law: V / highly variable R = highly variable I, which is a problem for voltage drive.
My usual 'fix' is to put a few ohms (or 100 or 1k, depending on how committed you are to the idea) in series. As long as the theoretical model is fairly accurate, where SPL is proportional to force exerted, which is some constant × the amount of current × the length of wire immersed in the magnetic field, the fix works to reduce modulation.
Say that in an extreme example with strong bass output, the speaker's "12.5 ohms" @ 5kHz varies between 10 and 15 ohms.
With class D or "conventional" voltage drive:
4V / (12.5 ± 2.5 ohm) = nominal 0.32A, highly modulated from 0.4A to 0.267A.
With 2 ohm output resistance tubes:
4.64V / (14.5 ±2.5 ohm) = nominal 0.32A,
high = 0.387A, low = 0.273A.
10 ohm added impedance:
7.2V / (22.5 ±2.5 ohm) = nominal 0.32A,
high = 0.36A, low = 0.288A.
22 ohms, etc...
Current drive with 1k ohm:
324V / (1012.5 ± 2.5 ohm) = nominal 0.32A,
high = 0.3208A, low = 0.3192A.
Klippel (et al) have enumerated dozens of related types of modulation. Just quickly (I don't want to hijack the whole thread) current through the voice coil also deflects the permanent field passing through the iron magnet poles. Depending on how much deflection occurs, the iron becomes either more or less saturated. When it's less saturated, it becomes more available as a core material for the voice coil, increasing inductance.
@lineup , I just thought that, as an amplifier designer, you may find these sort of hardware nuances interesting. There's definitely a lot of interplay between the electronics and how well the speaker will go.
The sound was far more full-bodied than my CHN-50's, but those are somewhat tighter and more crisp at high frequencies.
Extrapolating, I have high expectations for warm, jazzy bass from the 12P. And that's really the backbone. Getting the most out of the highs is probably the usual game with matching the speaker with a suitable amplifier (single digit damping factor, etc.)
300 Hz and up --> climbing impedance. Of course it looks a bit flattened, suggesting that the voice coil is loaded down by eddy currents in the surrounding metal (akin to secondary transformer windings, but with a small air gap). This reduces a particular type of modulation, where bass excursion modulates the physical position of the coil relative to the iron magnet poles, which in turn causes the impedance to get modulated away from the nominal values.
With Ohm's Law: V / highly variable R = highly variable I, which is a problem for voltage drive.
My usual 'fix' is to put a few ohms (or 100 or 1k, depending on how committed you are to the idea) in series. As long as the theoretical model is fairly accurate, where SPL is proportional to force exerted, which is some constant × the amount of current × the length of wire immersed in the magnetic field, the fix works to reduce modulation.
Say that in an extreme example with strong bass output, the speaker's "12.5 ohms" @ 5kHz varies between 10 and 15 ohms.
With class D or "conventional" voltage drive:
4V / (12.5 ± 2.5 ohm) = nominal 0.32A, highly modulated from 0.4A to 0.267A.
With 2 ohm output resistance tubes:
4.64V / (14.5 ±2.5 ohm) = nominal 0.32A,
high = 0.387A, low = 0.273A.
10 ohm added impedance:
7.2V / (22.5 ±2.5 ohm) = nominal 0.32A,
high = 0.36A, low = 0.288A.
22 ohms, etc...
Current drive with 1k ohm:
324V / (1012.5 ± 2.5 ohm) = nominal 0.32A,
high = 0.3208A, low = 0.3192A.
Klippel (et al) have enumerated dozens of related types of modulation. Just quickly (I don't want to hijack the whole thread) current through the voice coil also deflects the permanent field passing through the iron magnet poles. Depending on how much deflection occurs, the iron becomes either more or less saturated. When it's less saturated, it becomes more available as a core material for the voice coil, increasing inductance.
@lineup , I just thought that, as an amplifier designer, you may find these sort of hardware nuances interesting. There's definitely a lot of interplay between the electronics and how well the speaker will go.
Dave.
The acrylic gloss is similar to nail polish ? How do you apply it? You apply to the outer or inner surface of the cone ?
Dave,
Any hint how to do the coating ?
I paint the vanish on the cone with a small brush? Does this need to be of uniform in thickness ? I believe it is possible to use pressurized spray can too
What I did:
p.s. Put down a nano-layer by rolling driver over a block a "step" at a time; dip and fully tamp out both sides of the "sculpted" brush and nearly dry-brush the lower cone sector below dustcap; repeat.
Dave, what are your thoughts on phase plugs, do you have one for the 12P?
I have a dented dust cap that needs attention.
I have a dented dust cap that needs attention.
Have never installed them in any MA drivers.
But unless you can get a replacement cap it is likely the easiest way for a cosmetic fix. Depending on how bad it is it might be easiest to just live with them dented.
The way they are glued to the cone/VC removal will be different than most. You are likely to lose some top0, the DC acts much like tweeter dome.
dave
But unless you can get a replacement cap it is likely the easiest way for a cosmetic fix. Depending on how bad it is it might be easiest to just live with them dented.
The way they are glued to the cone/VC removal will be different than most. You are likely to lose some top0, the DC acts much like tweeter dome.
dave