Quattrofish,
Good to hear that you are finding the big MTMs more to your linking.
I am guessing that your phone SPL meter is not giving you accurate readings - 60dB or lower sounds very low. I searched on Google "What does 60 dB sound like" - and got results that said normal conversation happens at 60dB. I am assuming that you are driving these big speakers beyond normal conversation levels?
On the amp, 3.5 watts is also in the "flea-watt" range; and being a SET amp, I am assuming that the output impedance will be higher too. I've also experienced low powered tube amps running out of gas fairly quickly with 2 way speakers, whereas with a well designed solid state amp they have much more to offer. There are several fairly easy to build projects, at various levels of cash outlay.
Good to hear that you are finding the big MTMs more to your linking.
I am guessing that your phone SPL meter is not giving you accurate readings - 60dB or lower sounds very low. I searched on Google "What does 60 dB sound like" - and got results that said normal conversation happens at 60dB. I am assuming that you are driving these big speakers beyond normal conversation levels?
On the amp, 3.5 watts is also in the "flea-watt" range; and being a SET amp, I am assuming that the output impedance will be higher too. I've also experienced low powered tube amps running out of gas fairly quickly with 2 way speakers, whereas with a well designed solid state amp they have much more to offer. There are several fairly easy to build projects, at various levels of cash outlay.
OK. Time to stop being a wimp about measuring impedance. I remain, however, almost totally ignorant of what I'm doing despite a good bit of reading.
Simply following the circuit provided, I need a 1k ohm resistor, like this one:
https://www.mouser.com/ProductDetail/Vishay-Dale/CMF551K0000BHEB?qs=BpFtYU5tmpsqeBzAgCoCMw==
and an 8 ohm resistor, like this one to calibrate:
https://www.mouser.com/ProductDetail/Vishay-Dale/CMF551K0000BHEB?qs=BpFtYU5tmpsqeBzAgCoCMw==
A couple of minijacks, wire it up as per the diagram, and plug it into the headphone out and microphone in on my computer. I should be off to the races. Am I missing anything? Do I need greater power handling for the resistors?
Thanks
Mike
Quattrofish,
Good to hear that you are finding the big MTMs more to your linking.
I am guessing that your phone SPL meter is not giving you accurate readings - 60dB or lower sounds very low. I searched on Google "What does 60 dB sound like" - and got results that said normal conversation happens at 60dB. I am assuming that you are driving these big speakers beyond normal conversation levels?
On the amp, 3.5 watts is also in the "flea-watt" range; and being a SET amp, I am assuming that the output impedance will be higher too. I've also experienced low powered tube amps running out of gas fairly quickly with 2 way speakers, whereas with a well designed solid state amp they have much more to offer. There are several fairly easy to build projects, at various levels of cash outlay.
You may be right about the SPL meter. I figured it might be inaccurate, which is why I mentioned the source of my data. I'll see if REW can measure SPL while I listen to music.
I do listen at lower levels than most, but more than normal conversational volume.
Prior to this, I've only used the SET for single drivers. It did well, but I suspect some of what I interpreted as harshness at higher volumes may have been distortion/clipping. I'm looking around for different amplifiers to try before making any decisions.
Thanks for chiming in. How do you like your latest speakers, the 10f/rs225 FAST designed by X? I have the drivers, but don't know if or when I'm going to build them.
The 10F/RS225 FAST are nice speakers - they are quite satisfying with a wide genre of music. The sensitivity is probably around 82-83 dB (need to check), so it performs better with a moderately powerful amp. I also don't play that loud and can manage with a 25-35 watt amp, but with the recent 100 Class AB amp I built (xrk971's FH9HVX), I've found the sound more effortless and the bass more controlled.
I am using the Visaton B80 as a mid-tweeter with a modified XO which has a few different component values compared to the one that was originally developed for the Scan 10F.
I don't have an impedance sweep handy - need to dig that out or do a new one. I use DATS to do that and find the tool very handy. In addition to impedance sweeps, it can measure driver T&S parameters and also component values (resistors, capacitors, and inductors). I have an older version that works with Win 7, and hence need to fire up the Win 7 PC for that. For measuring SPL I use a Parts Express SPL meter - probably cost me <$25 - another handy tool to have. And of course, there are better models also.
I am using the Visaton B80 as a mid-tweeter with a modified XO which has a few different component values compared to the one that was originally developed for the Scan 10F.
I don't have an impedance sweep handy - need to dig that out or do a new one. I use DATS to do that and find the tool very handy. In addition to impedance sweeps, it can measure driver T&S parameters and also component values (resistors, capacitors, and inductors). I have an older version that works with Win 7, and hence need to fire up the Win 7 PC for that. For measuring SPL I use a Parts Express SPL meter - probably cost me <$25 - another handy tool to have. And of course, there are better models also.
So many questions I don’t know where to start.
We’re you considering any other designs in the MTM configuration?
What ohm(s) are these running at?
I’m definitely intimidated by that crossover. Was it difficult to assemble?
If you were to do it all over again, what would you have done differently?
Are there any nuances If your old speakers you miss?
Thanks
We’re you considering any other designs in the MTM configuration?
What ohm(s) are these running at?
I’m definitely intimidated by that crossover. Was it difficult to assemble?
If you were to do it all over again, what would you have done differently?
Are there any nuances If your old speakers you miss?
Thanks
Thanks Dave, if I understand that correctly, it dips down below 4 around 200hz? I assume that’s not uncommon of speakers rated at 4ohms? Is that around the crossover point? Looking at the FR graph is it safe to say that the 2nd 12PW is what’s keeping it afloat in terms of balanced sound? Would a 3rd make help flatten it out even more? I was looking at the box design on the MA site and it seemed a little bit flatter (on the bottom) while using only one 12PW. I also realize flat isn’t always or even usually the goal. Merely and humbly trying to learn before I bite the bullet and build something. This particular project interests me more than others I’ve seen. Very nice job on both the design and the build.
Date stamp on that graph is 5 years already- seems like just yesterday. Time is never more fluid than when one is retired.
As I recall notable that complex a build, but not definitely not small or budget parts. If I’d had the place for these, I certainly would have wanted to keep them, and the Neurochrome 686 amp I got a chance to hear them with at the last fest of Dave’s I attended.
As I recall notable that complex a build, but not definitely not small or budget parts. If I’d had the place for these, I certainly would have wanted to keep them, and the Neurochrome 686 amp I got a chance to hear them with at the last fest of Dave’s I attended.
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Hey there, 312.
Sorry for the delay in getting back to you. I haven't been on the forum much of late. Too happy with my speakers to have much of a need!
Dave took care of the technical stuff. Thanks, Dave!
The crossover was really quite simple. I had lots of questions, and made a few simple mistakes, due to my near-complete ignorance of how the components work. Dave was his usual, extremely helpful self and got me through it. The only downside was cost. Parts were around $400. We're all here to help you if you decide to give them a shot.
They have been playing perfectly since my last post, often for many hours per day. The sound is sublime, especially now that I am giving them more power. The 3.5 watts was definitely the source of many issues. I was able to obtain an LFD Mk III amplifier a couple of months ago and it changed EVERYTHING for the better. With 60 watts of refined SS power the mids and treble snapped into focus with better clarity, and the bass....oh, the bass. It is all there, with subtlety and amazing extension. I haven't re-tested, but I think they are fairly flat into the mid-20s (room modes aside).
What would I do differently? I would build the crossovers at the same time as the boxes, and put them inside. I've decided I'm going to put them inside after the fact, and it is going to be a major PITA. I would also pay more attention to Dave when he said to really tease out the poly fill. I wasted a lot of time and worry by not teasing it out nearly enough the first time.
My old MarKens sounded great. Amazing, really. These new ones are, I think, their equal or better in pretty much every way. The only exception may be imaging. I can't A/B them, but my (admittedly fading) memory tells me that the MarKens were just slightly more holographic in their presentation. Could be a dispersion issue with the wide/flat vs teardrop shapes. Could be the size of the enclosure or dampening. Could be my imagination. Tough to say, but I am not switching back. Any imaging degradation is more than made up for by the vastly improved mid-bass and bass. Plus, these had the crossover design, which allowed me to try a few amps very easily to dial in the sound.
Sorry for the delay in getting back to you. I haven't been on the forum much of late. Too happy with my speakers to have much of a need!
Dave took care of the technical stuff. Thanks, Dave!
The crossover was really quite simple. I had lots of questions, and made a few simple mistakes, due to my near-complete ignorance of how the components work. Dave was his usual, extremely helpful self and got me through it. The only downside was cost. Parts were around $400. We're all here to help you if you decide to give them a shot.
They have been playing perfectly since my last post, often for many hours per day. The sound is sublime, especially now that I am giving them more power. The 3.5 watts was definitely the source of many issues. I was able to obtain an LFD Mk III amplifier a couple of months ago and it changed EVERYTHING for the better. With 60 watts of refined SS power the mids and treble snapped into focus with better clarity, and the bass....oh, the bass. It is all there, with subtlety and amazing extension. I haven't re-tested, but I think they are fairly flat into the mid-20s (room modes aside).
What would I do differently? I would build the crossovers at the same time as the boxes, and put them inside. I've decided I'm going to put them inside after the fact, and it is going to be a major PITA. I would also pay more attention to Dave when he said to really tease out the poly fill. I wasted a lot of time and worry by not teasing it out nearly enough the first time.
My old MarKens sounded great. Amazing, really. These new ones are, I think, their equal or better in pretty much every way. The only exception may be imaging. I can't A/B them, but my (admittedly fading) memory tells me that the MarKens were just slightly more holographic in their presentation. Could be a dispersion issue with the wide/flat vs teardrop shapes. Could be the size of the enclosure or dampening. Could be my imagination. Tough to say, but I am not switching back. Any imaging degradation is more than made up for by the vastly improved mid-bass and bass. Plus, these had the crossover design, which allowed me to try a few amps very easily to dial in the sound.
It is the shape.
The Mar-Kens were designed as a modular system, 1 or 2 woofers, Almost any midTweeter you’d like.
They are harder to build, don’t go quite as low, driver spacing is not as tight, larger footprint, but offer versatility, that very low diffraction signature ("holographic imaging”). They have no official passive XO, the MTM one is probably close for an A7/A12pw MarKen MTM stack.
It is all about the trade-offs that are best for the individual.
dave