+1.The smaller the coil, the more slam the speaker has. No need for a new driver at all. It's the crossover that is plain useless. Whoops, outspoken again.
Without measurements, all this jibber jabber is a waste of time.
OK, the fact that rolling off the driver higher with a semi-sealed alignment just confirmed beyond any doubt that IME it's not the driver nor its cab alignment, but the XO and any BSC applied WRT room interaction as others have pointed out since any "light"/"diaphanous" 'tone' is typically due to an unbalanced harmonic structure relative to the fundamentals in the ~80 - 250 Hz BW.
D'Appolito's published dual driver TQWT [THOR] design is a wonderful example of this. Its presentation 'floated' like a thin veil through the very large, resonant concrete room I auditioned it in. No real bass to 'anchor' it or mid-bass 'slam' to add 'weight' to it and with extreme highs that were so elevated ['airy'] to the point of ~complete transparency.
http://www.audioxcel.com/audioXpress Thor Review.pdf
A surreal experience to my ears, but musically, a waste of time/effort/$$$ in mine and quite a few others opinions, so a few of us came up with other cab designs to acoustically address the lack of bass to offset stuffing losses and reduce the BSC required, though don't recall if anyone built any of the variations and/or whether they modded the XOs.
Of course we all hear the same, yet not so much, so ultimately, you may still not like the Vifa, but until you 'iron out' the XO to tonally balance the speakers in room, you have no way to know for sure and most likely, any other driver won't sound 'right' either.
Note that in many rooms and assuming no digital EQ is employed, each speaker's XO ideally needs to be individually 'voiced' to ensure the best stereo image, a procedure usually ignored.
GM
Many many thanks, I'm at least surprised about all these advices. Unfortunately I haven't any measurement, it was because of my lacks of instruments and experience that I've choosen a good and safe project to build as New Vifa Tower (however I've just decided I can't continue this way and step by step I'll build my right measurement lab!).
@GM: please let me understand, so do you think it's a cab design problem that causes the unbalanced harmonic structure relative to the fundamentals in the 80-250 Hz range?
How can I discover if it's really true? What can it be due to, to the form of cabinet, to the simmetric position of driver in the baffle, to distance from wall, to everything else?
And overall, how can I solve once found the real problem? Only by modding crossover or, better, by modding the form of cabinet? Yes..I can do it.. For example, if the problem is the simmetry of design, and if I don't go wrong this is a baffle step issue, can I solve by adding a sort of wing in the side of cabinet or however by modifing in some way the external shape to break the baffle step?
Or I must necessarily go tweaking cross-over? I don't understand if you're pro or versus this last solution, as suggested by "system7" in post #17-18 (at purpose, as said by "Cousin Billy" in post #19 using a 1.5 mH inductance or less this can cause the baffle step to appear: if so it would say that actual crossover compensates it, but this causes to me the attenuation of a pretty good piece of musical program and I really don't like this, so welcome baffle step!)
In conclusion, since I'd prefer much more solve a problem by removing the real reason rather than compensating and correcting the final result, what do you suggest to me: try correcting cabinet geometry, cabinet/room interaction, crossover?
However thank you all for the money you made me save.. : )
@GM: please let me understand, so do you think it's a cab design problem that causes the unbalanced harmonic structure relative to the fundamentals in the 80-250 Hz range?
How can I discover if it's really true? What can it be due to, to the form of cabinet, to the simmetric position of driver in the baffle, to distance from wall, to everything else?
And overall, how can I solve once found the real problem? Only by modding crossover or, better, by modding the form of cabinet? Yes..I can do it.. For example, if the problem is the simmetry of design, and if I don't go wrong this is a baffle step issue, can I solve by adding a sort of wing in the side of cabinet or however by modifing in some way the external shape to break the baffle step?
Or I must necessarily go tweaking cross-over? I don't understand if you're pro or versus this last solution, as suggested by "system7" in post #17-18 (at purpose, as said by "Cousin Billy" in post #19 using a 1.5 mH inductance or less this can cause the baffle step to appear: if so it would say that actual crossover compensates it, but this causes to me the attenuation of a pretty good piece of musical program and I really don't like this, so welcome baffle step!)
In conclusion, since I'd prefer much more solve a problem by removing the real reason rather than compensating and correcting the final result, what do you suggest to me: try correcting cabinet geometry, cabinet/room interaction, crossover?
However thank you all for the money you made me save.. : )
I really don't think you should fret about bafflestep here. It's just a word for bass boost really. You can have more or less of it according to taste and room placement.
If the speakers are close to a wall, you will need less. But the correction is rough and ready at best.
8" paper bass and tweeter is a particular interest of mine, since it has a very authoritatative sound when done well.
http://www.diyaudio.com/forums/multi-way/190129-8-1-two-way-diy-speakers-12.html
I prefer the less bassy small bass coil approach myself, since it sounds better and has more efficiency and places easily near a wall. Your cab is 10" wide, which is very typical.
Really that woofer of yours is a delight on frequency response. Needs very little work to sound good and has a natural rolloff at around 3kHz. Troels Gravesen and myself share a similar approach: TQWT-
My own experience of 8" drivers is that if you go above 1.5mH bass coil, it sounds overly bassy. Simple as that.
If the speakers are close to a wall, you will need less. But the correction is rough and ready at best.
8" paper bass and tweeter is a particular interest of mine, since it has a very authoritatative sound when done well.
http://www.diyaudio.com/forums/multi-way/190129-8-1-two-way-diy-speakers-12.html
I prefer the less bassy small bass coil approach myself, since it sounds better and has more efficiency and places easily near a wall. Your cab is 10" wide, which is very typical.
Really that woofer of yours is a delight on frequency response. Needs very little work to sound good and has a natural rolloff at around 3kHz. Troels Gravesen and myself share a similar approach: TQWT-
My own experience of 8" drivers is that if you go above 1.5mH bass coil, it sounds overly bassy. Simple as that.
Attachments
Thanks again for all your suggestion!
@System7, from post #17
What do you mean saying "Keep it around 8 ohms load to the filter" about the tweeter section?
All the best!
andrea
@System7, from post #17
Thank you in particular for your advice, that's what I will do in the next time. Just for a confirmation, is the attached picture of modifies right?
What do you mean saying "Keep it around 8 ohms load to the filter" about the tweeter section?
All the best!
andrea
Sorry so long in replying. I missed this one.
Yup the original advice stands. Smaller 1.5mH bafflestep coil and simple bass shunt. 3.9R and 4.7uF should be fine. It's a well behaved woofer that won't need a lot of work.
8 ohms load to the filter means you do the resistor sum assuming a 6 ohm tweeter, and keep the overall attenuator plus tweeter load around 8 or 9 ohms after the 3rd order tweeter filter. Without modelling it, that should keep impedance sensible. You don't want to present a near short at high frequency.
This may help. It's not dissimilar.
http://www.diyaudio.com/forums/multi-way/267688-fun-build-8-two-way-visaton-speaker.html
Yup the original advice stands. Smaller 1.5mH bafflestep coil and simple bass shunt. 3.9R and 4.7uF should be fine. It's a well behaved woofer that won't need a lot of work.
8 ohms load to the filter means you do the resistor sum assuming a 6 ohm tweeter, and keep the overall attenuator plus tweeter load around 8 or 9 ohms after the 3rd order tweeter filter. Without modelling it, that should keep impedance sensible. You don't want to present a near short at high frequency.
This may help. It's not dissimilar.
http://www.diyaudio.com/forums/multi-way/267688-fun-build-8-two-way-visaton-speaker.html
Attachments
Hello System7! How are you? About one month ago I applied the tweaking you suggested to my system and so I took some time to listen, really short time. Unfortunately the 1.5 mH coil didn't help me to obtain presence in mid-bass band, rather I obtained very much presence and something wrong in the mid-high, which of course in certain musical program can be pretty but generally I don't like.
In this time I learnt to use Boxsim with frd and zma file traced from datasheet graphs and so below I'll show simulation of that (dashed simulation of New Vifa Tower as original):
as you can see there's too much middle presence and too much visible breakup.
So I want to look for another solution. I've seen your project using Visaton drivers; looking for nice and punchy response in mid-bass band woofer I'm interested about Visaton GF200 with coils in series, becuase of its high Qms and BxL: do you know this woofer? Have you got a way of listening it?
Anyway what kind of woofer do you know able to give punchy and energetic mid-basses?
Alternatively, below a proposal for a tweak of mine for New Vifa Tower, with mid-bass slightly emphasized and lower cross point @ 1200 Hz, what do you think about?
Thanks a lot : )
In this time I learnt to use Boxsim with frd and zma file traced from datasheet graphs and so below I'll show simulation of that (dashed simulation of New Vifa Tower as original):
as you can see there's too much middle presence and too much visible breakup.
So I want to look for another solution. I've seen your project using Visaton drivers; looking for nice and punchy response in mid-bass band woofer I'm interested about Visaton GF200 with coils in series, becuase of its high Qms and BxL: do you know this woofer? Have you got a way of listening it?
Anyway what kind of woofer do you know able to give punchy and energetic mid-basses?
Alternatively, below a proposal for a tweak of mine for New Vifa Tower, with mid-bass slightly emphasized and lower cross point @ 1200 Hz, what do you think about?
Thanks a lot : )
Hi,
Lots of handwaving, waffle and opinionated rubbish, is
not going to help you a lot in sorting out your dilemna.
New drivers won't help and will be a world of pain.
http://www.datasheets.pl/SPEAKERS/VIFA/M21WO3908.pdf
The MB x/o certainly has BSC, and the big inductor is needed
due to the drivers quite high Le and rising top end response.
TBH I cannot work out the problem you are trying to fix.
IMO you need to detune the box to 28Hz,
that will certainly tune the 50 to 150Hz area.
rgds, sreten.
"For more than one year I've tried to improve this decreasing internal volume,
shortening the vent tube, attenuating tweeter, but what I got was always
boomy effect and need to return to the original configuration."
None of the above will help. Try making the port longer.
Try increasing the foam lining to say about 2" all round.
Reduce tweeter attenuation a little whilst unwinding
the inductor a little. Analyse your room for modes
and carefully look at speaker placement.
Lots of handwaving, waffle and opinionated rubbish, is
not going to help you a lot in sorting out your dilemna.
New drivers won't help and will be a world of pain.
http://www.datasheets.pl/SPEAKERS/VIFA/M21WO3908.pdf
The MB x/o certainly has BSC, and the big inductor is needed
due to the drivers quite high Le and rising top end response.
TBH I cannot work out the problem you are trying to fix.
IMO you need to detune the box to 28Hz,
that will certainly tune the 50 to 150Hz area.
rgds, sreten.
"For more than one year I've tried to improve this decreasing internal volume,
shortening the vent tube, attenuating tweeter, but what I got was always
boomy effect and need to return to the original configuration."
None of the above will help. Try making the port longer.
Try increasing the foam lining to say about 2" all round.
Reduce tweeter attenuation a little whilst unwinding
the inductor a little. Analyse your room for modes
and carefully look at speaker placement.
Last edited:
It is time for a review, I think.
We are looking at a big reflex like the WLM La Scala one on the left.
I think that will be a bit of a boom box by its very nature. Deep bass interacts with room gain.
The filter cannot totally correct that initial design choice. The bass reponse also seems to have a problematic tendency to bend at 1kHz when filtered looking at your modelling.
You could look at a 2.5kHz Troels design here for inspiration:
QUATTRO-mkII
Or persist with that 3kHz near LR4 filter that works for me.
An externally hosted image should be here but it was not working when we last tested it.
We are looking at a big reflex like the WLM La Scala one on the left.
I think that will be a bit of a boom box by its very nature. Deep bass interacts with room gain.
The filter cannot totally correct that initial design choice. The bass reponse also seems to have a problematic tendency to bend at 1kHz when filtered looking at your modelling.
You could look at a 2.5kHz Troels design here for inspiration:
QUATTRO-mkII
Or persist with that 3kHz near LR4 filter that works for me.
Attachments
Hello Sreten, I understand what you mean but trust me, as I talked about in my new thread there's nothing else I can do and nothing else I want to do, I've tried everything but hte problem is really my woofer, or if we want its belonging category or working philosophy, i.e. the mechanically overdamped/overcontrolled woofer, which is the most common in the high-end audio sector.
Simply I'm tired of extreme linearity, highest tonal balance or ultralow distortion, what I want is life, joy and fun by sound. Let me say I find more attractive music if I listen it by the my series Lancia Y car radio or, by memory, from my brother's old stereo, because of its "live" mid-bass band. It's a timbre question, I prefer a woofer which "sings" even slightly unfaithful but "sings".
All I'm looking for is so a nice timbre and audible strenght in mid-bass band.
Vifa, like somebody said, is "a delight" in frequency response, undoubtly, but simply it's not my first need.
Simply I'm tired of extreme linearity, highest tonal balance or ultralow distortion, what I want is life, joy and fun by sound. Let me say I find more attractive music if I listen it by the my series Lancia Y car radio or, by memory, from my brother's old stereo, because of its "live" mid-bass band. It's a timbre question, I prefer a woofer which "sings" even slightly unfaithful but "sings".
All I'm looking for is so a nice timbre and audible strenght in mid-bass band.
Vifa, like somebody said, is "a delight" in frequency response, undoubtly, but simply it's not my first need.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.