If I were you, I would build a slim 3-way tower.
Use 2 units of SB15NRXC30-8 for the bass. Get a new 4" or 5" driver with a nice flat response that I can easily cross to the Seas tweeter at 2.2kHz.
Trying to cross the SB15NRXC30-8 with a tweeter is asking for trouble. It is more suitable for bass.
Use 2 units of SB15NRXC30-8 for the bass. Get a new 4" or 5" driver with a nice flat response that I can easily cross to the Seas tweeter at 2.2kHz.
Trying to cross the SB15NRXC30-8 with a tweeter is asking for trouble. It is more suitable for bass.
You're right on point with the long term plan - to use two 15NRXC30-8's in parallel with the 12MNRX25-4 and the seas tweeters in a slim floor standing form factor. The pair of 15's will give enough output to deal with baffle step and a bit of low end, without going too low in this flat. The midrange is a dedicated midrange design so should sound superb in a dedicated sealed volume, the only variance in my current plan is to use a 350/3500 xo point, which seems to make a lot more sense in many ways, why would you suggest 2.2kHz? it seems a very low crossover point for a dedicated midrange... also, I should point out that the 15NRXC30-8 is used in parallel in zaph's SB12.3 design as a dedicated midrange, but crossed at 220/2200, so should be highly capable in a 2-way
Hi Nannoo, if you want good (and large) caps that won't break the bank then you can't go past the axon's from parts connexion IMO AXON True Cap Metallized Polypropylene Capacitors They are what I used in my crossover (for all areas).
The problem I had with my MTM's with baffle step was a hump between about 900Hz and 1.4Khz. I got rid of it with a parallel notch in series with the driver. But I have recently discovered that a series notch in paralell with the driver can have the same effect (and probably with less impact on the impedance).
Knocking down this peak but not going for full baffle step compensation may be a good compromise. Once you have your measurements sorted you will have a better idea as to what may be an option.
Are you using tube amps? I didn't worry so much about peaks in my speakers impedance just the dips, but I could be ignoring something important!
Tony.
The problem I had with my MTM's with baffle step was a hump between about 900Hz and 1.4Khz. I got rid of it with a parallel notch in series with the driver. But I have recently discovered that a series notch in paralell with the driver can have the same effect (and probably with less impact on the impedance).
Knocking down this peak but not going for full baffle step compensation may be a good compromise. Once you have your measurements sorted you will have a better idea as to what may be an option.
Are you using tube amps? I didn't worry so much about peaks in my speakers impedance just the dips, but I could be ignoring something important!
Tony.
wintermute,
not sure if they have a UK supplier, but TBH i think as soon as you get away from electrolytics you're in safe teritory, I'm not mad keen on expensive caps - just as long as the value is right. I'm happy with solen or m-caps, and until I have a £5k+ system I don't think there's much point in upgrading 😉
not sure if they have a UK supplier, but TBH i think as soon as you get away from electrolytics you're in safe teritory, I'm not mad keen on expensive caps - just as long as the value is right. I'm happy with solen or m-caps, and until I have a £5k+ system I don't think there's much point in upgrading 😉
hi nannoo
It's not that the SB15NRXC30-8 cannot be used in a 2-way. It's just more difficult. I would rather use my Audax HM130C0. I don't have to wrestle with it.
When I design speakers, I like the vocals to be very transparent and slightly forward. For drivers up to 5 1/4", I find that crossing at 2.2kHz gives me that. It gets lower as the woofer gets larger. For a 10", my preference is 1.25kHz - 1.5kHz.
It's not that the SB15NRXC30-8 cannot be used in a 2-way. It's just more difficult. I would rather use my Audax HM130C0. I don't have to wrestle with it.
When I design speakers, I like the vocals to be very transparent and slightly forward. For drivers up to 5 1/4", I find that crossing at 2.2kHz gives me that. It gets lower as the woofer gets larger. For a 10", my preference is 1.25kHz - 1.5kHz.
Note that that price at parts connexion is roughly 50% RRP. So even if you do find a UK supplier they might not be able to match the price. If the order is under 250g (including the packaging) the shipping is reasonable (under $10 US the last time I ordered a few years ago). It doubles in cost between 250 and 500g, once you go over 500g you are probably looking at at least $50 US for shipping.
Tony.
Tony.
Hi tony,
With respect to the problem of impedance, I have a few "gut instinct problems" which may well be founded in the limitations of my electrical engineering ability.
One example of this, I used to think parallel crossovers were inherently wrong by nature, on the principle that all things being equal passing a voltage at a certain frequency accross two drivers could allow for a much larger power output at that frequency-by nature, series could resolve that issue for us. Interestingly this can be seen by how nicely theoretical first order series neworks interact in simulations. The problem is that first order is always never practical and higher order series networks loose a lot of the initial advantages.
When it comes to amplifiers, along the same lines, if they are simple voltage amplifiers and power is equal to voltage squared over resistance/impedance, surely any variation in impedance across frequency for the speaker will result in a variation in power response dependant on the characteristics of the amplifier, but none the less undesirable?
With respect to the problem of impedance, I have a few "gut instinct problems" which may well be founded in the limitations of my electrical engineering ability.
One example of this, I used to think parallel crossovers were inherently wrong by nature, on the principle that all things being equal passing a voltage at a certain frequency accross two drivers could allow for a much larger power output at that frequency-by nature, series could resolve that issue for us. Interestingly this can be seen by how nicely theoretical first order series neworks interact in simulations. The problem is that first order is always never practical and higher order series networks loose a lot of the initial advantages.
When it comes to amplifiers, along the same lines, if they are simple voltage amplifiers and power is equal to voltage squared over resistance/impedance, surely any variation in impedance across frequency for the speaker will result in a variation in power response dependant on the characteristics of the amplifier, but none the less undesirable?
I dont know where in UK you are nannoo but, as far as caps are concerned, I was looking at possibly Ansar caps, from Cricklewood Electronics, or Mundorf Evo, from HiFiCollective. Both seem to have good feedback and reasonably priced. Or Wilmslow do standard MKP's pretty cheap (ie: 15uF for £4.80) again they seem to get reasonable feedback for the price. I haven't personally heard them yet.
The Audax was another driver I was looking at, how does it compare with the SB soundwise with regards voices, strings, etc...?
The Audax was another driver I was looking at, how does it compare with the SB soundwise with regards voices, strings, etc...?
Gracol
I've not worked on any SB drivers, so can't really comment.
However, comparing to the Dayton, HiVi, Peerless, Seas and other drivers that I have, none of them comes close.
The vocals and strings of this Audax is unbelievable. I fell in love with it instantly. Presently, it's with a small, vintage AMT.
One thing to note with the Audax is bass is rather limited, even when ported. It's not a problem when used in near field monitoring of vocals, particularly female voices but for full range music listening, it needs to be supported by a bass woofer.
I've not worked on any SB drivers, so can't really comment.
However, comparing to the Dayton, HiVi, Peerless, Seas and other drivers that I have, none of them comes close.
The vocals and strings of this Audax is unbelievable. I fell in love with it instantly. Presently, it's with a small, vintage AMT.
One thing to note with the Audax is bass is rather limited, even when ported. It's not a problem when used in near field monitoring of vocals, particularly female voices but for full range music listening, it needs to be supported by a bass woofer.
Thanks Michael, thats very interesting. I have read quite mixed reviews about the Audax but sounds like a definite contender to me.
I will be pairing whatever I end up building with a sub (also yet to be built), probably crossing with the speakers around 80Hz or so, so lower end isn't so important. Though, in saying that, would be handy to have some lower end for late night listening so the sub isn't being used.
Food for thought, thanks!!
I will be pairing whatever I end up building with a sub (also yet to be built), probably crossing with the speakers around 80Hz or so, so lower end isn't so important. Though, in saying that, would be handy to have some lower end for late night listening so the sub isn't being used.
Food for thought, thanks!!
Hi Nannoo, sorry I don't know the answers but I see you have started a new thread on the specifics of the speakers impedance so hopefully that sheds some light. But I guess in general you are correct, now that I think about it.
Where I have placed parallel notch filters (in series with drivers) they cause a spike in the impedance curve at that frequency. Since the desired result of the notch is a reduction in output, I guess this is the desired behaviour since the amount of power the amp can deliver at that frequency will be lower. The voltage I guess remains the same, but the current has reduced, and therefore so has the power (at that frequency).
Above purely from a layman's point of view 🙂 my electrical theory extends a little past ohms law 😉
Tony.
Where I have placed parallel notch filters (in series with drivers) they cause a spike in the impedance curve at that frequency. Since the desired result of the notch is a reduction in output, I guess this is the desired behaviour since the amount of power the amp can deliver at that frequency will be lower. The voltage I guess remains the same, but the current has reduced, and therefore so has the power (at that frequency).
Above purely from a layman's point of view 🙂 my electrical theory extends a little past ohms law 😉
Tony.
Hi I also bought the same sb 5inch mid bass drivers from Falcon acoustics , I am on a tight budget can anyone suggest a good matching sb tweeter ? my intention is to build some small 2 way front ported speakers . I also need some help with the cross over 🙂
2 way design in 0.25 cuft (7l) with port and 29RDNC
SB15NRXC30-4 + SB29RDNC 2-way Passive Crossover Design - Madisound Speaker PDF Library
SB Acoustics SB29RDNC-C000-4 Tweeter
SB15NRXC30-4 + SB29RDNC 2-way Passive Crossover Design - Madisound Speaker PDF Library
SB Acoustics SB29RDNC-C000-4 Tweeter