Minidsp 2x4HD is what was recommended! The non-HD unit is much inferior and outdated.
Another modestly priced option is from Dayton.
https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd
https://www.daytonaudio.com/product...gital-signal-processor-for-home-and-car-audio
Another modestly priced option is from Dayton.
https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd
https://www.daytonaudio.com/product...gital-signal-processor-for-home-and-car-audio
Absolutely this ^^^
Don't fret over second place decimals in a sealed enclosure. In reality it will be corrected when EQ is applied and nobody will be any the wiser. Power compression can be a problem if driving big sealed enclosures hard, so in my PA setup the magnets are on the outside, in dare I say it, car audio style!
Frank 207be mentioned the B&C 21SW15; I built a ported enclosure for a customer using one and it is a bit of a brute! Very, very nice, good output, but of course did not sound as good as a sealed enclosure...
On the subject of DSP, chances are that it any model be more than capable of keeping up, sound quality-wise, with most vintage gear.
What size enclosure and tuning? I previously had them in 540L enclosures with a 11Hz tuning and I sometimes miss the pressure in that range. OTOH I was glad to get rid of the horrible port noise.
Oh wow - how bad must have been the old one ... this is from the HD version:
https://www.audiosciencereview.com/...urements-and-minidsp-2x4-hd-dsp-and-dac.2674/
While the newer MiniDSP stuff seems to be good I always have trouble with the older ones. There is a reason why they didn't specify S/N and THD with these units.
Quite a lot of info to process here, I am going to have to digest everything about drivers and get back to everyone with some questions about those later.
@IamJF I am not really sure whether for the design I've got a high or low Qms or what the XMAX really entails... I can imagine how a higher XMAX would give you a higher SPL at a given frequency before distortion or damage.
On DSP
Having read a little more about miniDSP I am actually a bit put off by their driver/software model. I don't really like the idea that I'll buy some hardware and will then be able to download the software once.
I've also been looking at DBX Driverack PA2. Which looks substantial but I am still working out whether it can be using with unbalanced RCA inputs and output to RCA too at consumer hifi levels. The connections on the unit are all XLR but it's user manual gives you the schematics for RCA to XLR and there is apparently a "+4dBu/-10dBv Switch" for use with RCA devices, but it doesn't say what the does the output. I have no intention of replacing my preamp or amp for XLR gear.. yet (although I imagine whatever amp I use for my sub will probably use it).
@IamJF I am not really sure whether for the design I've got a high or low Qms or what the XMAX really entails... I can imagine how a higher XMAX would give you a higher SPL at a given frequency before distortion or damage.
On DSP
Having read a little more about miniDSP I am actually a bit put off by their driver/software model. I don't really like the idea that I'll buy some hardware and will then be able to download the software once.
I've also been looking at DBX Driverack PA2. Which looks substantial but I am still working out whether it can be using with unbalanced RCA inputs and output to RCA too at consumer hifi levels. The connections on the unit are all XLR but it's user manual gives you the schematics for RCA to XLR and there is apparently a "+4dBu/-10dBv Switch" for use with RCA devices, but it doesn't say what the does the output. I have no intention of replacing my preamp or amp for XLR gear.. yet (although I imagine whatever amp I use for my sub will probably use it).
dobson156
When choosing a solution, you should to answer the question - what level of sound quality do you want to achieve?If you just want to add a lot of bass to your existing system and make everything sound loud, you can use DSP. They have one undeniable advantage - ease of adjustment and tuning.
If you want to get a high quality sound of the whole system, then the use of any DSP will not give you the maximum sound quality. it is better to use not modern active analog crossovers of my grandfather's time, but still giving the maximum quality. This is very noticeable when using high quality speakers like your KEFs
The task will be much easier if you tell us what amplifiers and DACs you are going to use.
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Having read a little more about miniDSP I am actually a bit put off by their driver/software model. I don't really like the idea that I'll buy some hardware and will then be able to download the software once
That's not correrct, don't believe all that they write at ASR! Once you have registered as a customer/produt(s), you have access to software and plugins, no time limit. Also for legacy models. Perhaps they used "once" in meaning of "after" you have registered.
Lately minidsp has released a new universal "Device Console" https://docs.minidsp.com/product-manuals/2x4-hd/device-console.html but I have no plans to update ( I have three 2x4HD units in use, my 4x10HD broke after 9 years)
This thread seems to get into argument about "best system". I quit now.
That's not correrct, don't believe all that they write at ASR! Once you have registered as a customer/produt(s), you have access to software and plugins, no time limit. Also for legacy models. Perhaps they used "once" in meaning of "after" you have registered.
Lately minidsp has released a new universal "Device Console" https://docs.minidsp.com/product-manuals/2x4-hd/device-console.html but I have no plans to update ( I have three 2x4HD units in use, my 4x10HD broke after 9 years)
This thread seems to get into argument about "best system". I quit now.
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My stack currently is:
- Rega DAC
- Manticore Turntable with AT540ML
- Croft Super Micro preamp
- Quad 606 for the mains
I listen to all sorts of music, but that does include loads of bass heavy electronic music as well as reggae and dub and so forth.
I am not looking for a comically over powered bass, but I really want that feeling you get from a system producing really low notes with competence
I think in the long run I will use DSP to figure out where the cross overs and EQs should be, and then design a crossover network to emulate that. But won't be for quite some time.
dobson156
What version of KEF105 do you have?what room size do you want to sound?
Forgive me for stepping into your plans. But the KEF are great speakers that can produce very impressive bass. I would first upgrade the existing set up.
1. quad is a good amp, I had a 909. But it doesn't give as much control over the speakers as, say the americans, macintosh, classe, krell, etc and even plinius, especially on bass. You need at least 200 watts of rms. These speakers have a sensitivity of 86dB only.
2. due to old age the speaker terminals are already oxidized. It is necessary to change the terminals, wires to the crossover and to the drivers on as thick as possible. Throw out indication circuits, fuses. in cross replace at least all electrolytic capacitors.
After these operations possible that you will change your mind about installing a sub 😊
Hard to believe, logic says that 21 inch is better than 12, but very often when playing music the sub only obstructs. For home theater, a sub is useful of course .
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No, it's overkill already IMO/IME, i.e. meant more bracing based on my way which in principle are like Dave p10's/Scottmoose's various designs.
Relative to BB, etc., plywoods per my bracing link, MDF is a poor choice for bracing except in the form of multiple layer mass loading.
As for any tonal differences that might occur between my way of bracing vs the overkill way (if any in this case considering who designed/built it) requires one to listen to the driver in free air so its box loading BW (Fhm = 2*Fs/Qts') is dipole rolled off and once in cab its tone should still be intact, just with added 'body'/'fullness'.
(Qts'): (Qts) + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html
A low sensitivity 12" driver having a true continuous rating of perhaps 100W or so is never going to be able to reproduce low bass at a level the OP has alluded to. Physics does not allow it.
Quick thoughts on subs and music as I'm currently tuning/evaluating my system:
Peaking/boomy bass ruins the whole thing, if balance of the system is not right "quality" of sound is gone. Peaky bass seems to ruin the whole midrange for example and all you hear is lows and highs 😀 About the most important thing is to get the system balance right, prerequisite for any other qualities of playback systems in my opinion. Or perhaps not prerequisite but a thing that needs to be right for good sound. Integration of sub to mains and how the whole system interacts with room and what the sound is at listening position is key thing. Positioning must be good and effect of room (modes) must be equalized by what ever means, this means DSP for domestic rooms.
Failing to balance the system then I also agree that subs are no very useful, it would be better to reduce nasty lows what ever means. But if there is possibility and intention to set up the system correctly then the subs make the sound complete, a good thing that completes playback system making it full bandwidth of good sound with nice loud SPL capability. Main purpose of the whole system, idea of subs, is to enable this, full bandwidth nice balanced sound in room. In other words achieve very good sound quality covering whole audible bandwidth.
Peaking/boomy bass ruins the whole thing, if balance of the system is not right "quality" of sound is gone. Peaky bass seems to ruin the whole midrange for example and all you hear is lows and highs 😀 About the most important thing is to get the system balance right, prerequisite for any other qualities of playback systems in my opinion. Or perhaps not prerequisite but a thing that needs to be right for good sound. Integration of sub to mains and how the whole system interacts with room and what the sound is at listening position is key thing. Positioning must be good and effect of room (modes) must be equalized by what ever means, this means DSP for domestic rooms.
Failing to balance the system then I also agree that subs are no very useful, it would be better to reduce nasty lows what ever means. But if there is possibility and intention to set up the system correctly then the subs make the sound complete, a good thing that completes playback system making it full bandwidth of good sound with nice loud SPL capability. Main purpose of the whole system, idea of subs, is to enable this, full bandwidth nice balanced sound in room. In other words achieve very good sound quality covering whole audible bandwidth.
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- Pretty sure it's the first version of the Kef Reference 105. The previous owner had them serviced and recapped in 2010 (with receipts to prove).
- Room is about 5x7 or so. But not perfectly square so if anything a bit bigger.
- I've been looking at a Meridian 557. Again they can be had reasonably cheaply here. McIntosh etc... is kinda out of budget for now. Not in a hurry to replace the 606. I guess if I add a sub and give it's own amp then the 606 doesn't need to even bother with frequencies it'll struggle with.
- Speaker terminals seem to have been replace when the unit was serviced in 2010. At leat the ones that go into the bass cabs. Will need to check the main ones.
- Fuses have been jumped by the previous owner... indication circuits still intact.. but to be honest I want to keep them and put the fuses back. I know the 606 isn't really powerful enough to blow them... but the reason I got the 105s is because blew some 104s which I still feel bad about 🙄 (In the process of fixing them as my current project). I'd like to do everything in my power to not let that happen again, even if that means degrade the fidelity ever so slightly.
- I hear you about 12x2 vs 21. But I do listen to a lot of bass heavy music... I know there is still "information" below what the 105s can give me. The 105s do a REALLY good job at replicating the frequencies it can reveal, but there are very clearly frequencies it just can't do. I won't be surprised if I end up with a small "switcher" circuit that lets me flick between DSP + Subs and no DSP no Sub depending on what sort of music I am listening to.
Hope that clears some things up
Spoken like someone who never used a serious DSP, dosn't know what to do with it, has no idea about gain staging and acoustic measurements. Sorry.
Noise and THD of these old analog crossovers are pretty bad to modern standards. Often a grave of old OPAs, but even the good ones are far from a great DAC. A good gain structure and your DA conversion as late in the chain as possible gives clean and detailed but also relaxed sound.
Unless you are LOOKING for a special sound ... then just use whatever gives you that.
p.s.: For good integration of a woofer in a room + system you need to do acoustic measurements! Don't do some ear-guesswork and blame the DSP if it doesn't work. 1) find the right spot for the woofer for even distribution of the sound. 2) EQing the worst peaks. 3) set crossover to main speakers 4) find the right delay 5) fine tune with measurements and listening!
You have this version?
https://www.audiovintage.fr/leforum...cs.net/pics/226606kef105212001600vertical.jpg
Seems to have good low extension but falling of slowly. Understand that you want more level there.
Is this a closed enclosure or Reflex? (Tube at the bottom?) Looks like closed but frequency response falls to steep for that.
Do you have a measurement microphone? I would start with analysing what you have now - a good way to learn about acoustic measurements which you need anyways for a proper sub integration.
These speakers would also be perfect to redo as semi/active version. You can use your amp for mid/high and an active module for the low frequency driver. So you can adapt the frequency response to your room and likeing and get more precision and get rid of the lf frequency divider parts. Or get a 2 way module and feed both with the same amps. From the measurements it seems like there could be a little to much 1kHz in the room but looks pretty good everything else - worth a try. And of course you could do proper limiting to protect your speakers.
But that's not a beginners project, you need to know what you are doing here.
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This is kind of my thoughts. I do understand and respect the comments made above about getting more out of my bass cabs out of my 105s. But I know there are limitations to what they'll be able to do, and I know what it is I am searching for and I know the 105s are really going to struggle to deliver it.
This project is by no means going to be the end of the journey, it's a stopping off point that I think will be interesting along the way, after which I can look further into DSP, active crossovers, room treatments, amplifier choices... and so on.
As I've said, I've got one more big question about drivers coming up that I still need to formulate and then I'll be getting my credit card out and seeing what happens.
My motto for clean bass is: "Move a lot of air - GENTLY!".
With this in mind, and for not much more money than a single a PD you could have a pair of the latest Beyma QLEX drivers, with more than double the power handling and 2.7 times the displacement! Power-friendly 4 ohm load too. Food for thought perhaps?
With this in mind, and for not much more money than a single a PD you could have a pair of the latest Beyma QLEX drivers, with more than double the power handling and 2.7 times the displacement! Power-friendly 4 ohm load too. Food for thought perhaps?