Seas Loki coaxial kit

[Bent]

Seas has a coaxial driver, madisound offers a turnkey kit with crossover board included. http://www.madisound.com/catalog/pro...oducts_id=1696
Can anybody share any details about this driver, or what their impressions of it are?
I hope I'm not breaking any rules, as I am aware that this is a retail link....
Delete it and scold me if you wish. :E

[Dennis H]

I can't comment on the sound but discussing it should be no problem as the design is in the public domain. I think Bjorn at Seas designed the crossover. This is for the older coax but, as I recall, Bjorn said no changes for the newer one.

[Jonasz]

I believe Dennis Murphy has a crossover for this driver.

[hawkfan]

I believe Dennis Murphy has a crossover for this driver.

Where?

[TacoD]

Seas has a coaxial driver, madisound offers a turnkey kit with crossover board included. http://www.madisound.com/catalog/pro...oducts_id=1696
Can anybody share any details about this driver, or what their impressions of it are?
I hope I'm not breaking any rules, as I am aware that this is a retail link....
Delete it and scold me if you wish. :E

Those Seas coax drivers are nice sounding, but are not the last word in definition. I listened to these configured as a 2-way and in a 2.5-way system. Both systems showed the potential of the driver, but personally I would do a 3-way setup. In an 2-way the sound stage collapses when used at higher spl levels.

[Jonasz]

Where?

I remember reading somewhere he was struggling with it for a long time before finding the right formula. I would suggest you email him and ask. I don't think he has it on the homepage...

[Mark Seaton]

The biggest hurdle with any of the common coax drivers is making sure the driver rarely operates out of its linear excursion range and to keep excursion in check. A 3 way system or a reflex 2 way augmented with a subwoofer is the easiest means to keep this in check. With many of the coax drivers I've also seen the upper midrange reflections inside the box related to depth as a significant hurdle that needs to be addressed in the design/use. While I've mostly moved on to more powerful coax's now, the SEAS coax can sound very good within its volume limits. In general the sound is better than the somewhat rough measurements would suggest.

[Dennis H]

While I've mostly moved on to more powerful coax's now...

Which ones do you like, Mark? Seems like I recall you using B&C? Have you tried any of the BMS coaxes? A couple of them look pretty tasty.

[SQconstable]

Yeah I'd like to inquire too! I want powerful hehe

[Mark Seaton]

I hope to experiment with both the BMS & 18 Sound coaxials, and at some point I'll move on to having my own custom built.

I tend to have some different targets and requirements, and most of my recent systems have been fully active, where the passive crossover for the HF gets to be rather complex with many drivers, especially with the compression drivers. It can be done passively, but the crossover design is far from simple if you want to use the full low frequency power of the compression drivers. The Eminence coax's are actually rather nice when used in a 3 way (check the JTR products I've had a big hand in). The Eminence drivers will have one or two notches in the HF response that will not be as severe with some of the best coaxes, but notches are benign in listening and I would argue the power response and sensitivity to be well worth it.

The Sellenium 210 and possible 220 (haven't tested it yet), have proven rather easy to use with passive crossovers and the cost is very reasonable. The BMS thread on driver is very powerful and extended, but requires more work on the frequency response. The newest B&C 8" coax probably has one of the best behaved compression drivers of the coaxes I have tested, but definitely requires some careful response shaping. If PE starts carrying it, you can thank me. Of course getting a good subjective ballance is hugely dependent on the crossover, and unless you are comfortable with rather complex crossovers with multiple, interacting notch filters, external EQ is very welcome.

[Dennis H]

most of my recent systems have been fully active

Are you using the SpeakerPower DSP/amp units? They look pretty interesting. Not exactly plug 'n play but it looks like they will do about anything if you can figure out the TI software. Will they sell to individual DIYers?

[Mark Seaton]

Are you using the SpeakerPower DSP/amp units? They look pretty interesting. Not exactly plug 'n play but it looks like they will do about anything if you can figure out the TI software. Will they sell to individual DIYers?

It appears enough have done some digging online to find the SpeakerPower amplifiers as the look is unique enough. Yes, these are the amplifiers I use, with a few customizations and modifications per the product application. The amplifiers are much more expensive than other similarly rated options, but the quality is top notch, and offers a lot of flexibility if you have time to really figure out the DSP. SpeakerPower does not sell to DIYers, as even at 2-3x the OEM price, the support required would not make it worth it. You need the specific interface box to program the amplifiers, and it is not useful for continous adjustment. Most all using them start with a conventional, external DSP device to get things close, and then make final adjustments through a very tedious process with the 2 separate programs and no real-time adjustment capability. Yes, it's a PITA. Fortunately once it is programmed it is very stable, which is more than can be said for the connection of the software and the amplifier. :banghead:

Support for OEMs with long term relationships is well above par. Cost is very high in the plate amplifier world, yet very reasonable when compared to what is actually delivered with separate components using the larger ICEpower modules, and delivering its power ratings without the use of fans.

I can't see any case where a DIYer would not be better off utilizing an external DSP box like the in-expensive DCX2496 or any of the larger matrix DSP options in conjuction with some multi-channel amplifiers. In standard form they really are not optimized for home audio use, and the interface is certainly not either. That may change to some degree before the end of the year, but I know SpeakerPower has made it clear they don't have the resources available to support DIYers. The significant advantages afforded me in the SpeakerPower solution is of minimal interest or value to most DIYers, and adds significant cost which are unlikey to be chosen in the face of other less expensive options available.

I suspect some of the current projects underway here on HT guide will serve to highlight the complexities of some more desirable 3+way configurations which can become quite troublesome to implement passive crossovers for. Such cases are prime examples where active systems make a lot of sense for the DIYer where your crossover choices are not limited by network impedance requirements. Likewise, if you look at the response shapes and impedance curves of many compression drivers, it should be obvious that simple passive networks will never get the response as flat as many are used to with a dome tweeter. Once you weed out the really poor horns, the response becomes a huge factor in the classically attributed sounds, and the complexity in designing a passive crossover for such systems plays no small part in that perception.

[SQconstable]

I always wondered the approach of Mackie's HR824's. They're very flat in their 2-way response and it is obvious that the tweaking was done on the pre-amp end. I bet the best sound will always be derived from such. Passive crossovers become a compromise when active solutions become that effective.

[Mark Seaton]

I always wondered the approach of Mackie's HR824's. They're very flat in their 2-way response and it is obvious that the tweaking was done on the pre-amp end. I bet the best sound will always be derived from such. Passive crossovers become a compromise when active solutions become that effective.

I would say that your observation is important, but the dismissal of the passive approach is premature. Many like to look at driver selection and physical layout as a separate process from the crossover implementation. Doing so greatly limits possible and potentially beneficial options.

In designing more 3-way passive systems along with fully active systems, it is clear where much of the old-school thought of >2 way systems being very difficult or expensive to integrate. Whether it be a passive or active system, designing from the system perspective rather than the isolated component perspective will save a lot of headache and self imposed limitations to deal with later. Passive crossovers where narrower bandpasses are probably the best example of this, in particular when a driver is crossed within 2 octaves of its low frequency corner. While a complex enough crossover can tame most beasts, you can often cut the component count to 1/2 or 1/4 by choosing a driver which at first glance isn't as flat or otherwise doesn't fit the target... until you put a network on it.

From the active system perspective (assuming DSP w/PEQ), you instantly add the ability to easily smooth response shapes which can be a royal pain to correct in a passive crossover given the many interacting components. If you then further focus on the total system response rather than looking for the perfectly flat response drivers, you can focus instead on efficiency, real power(I^2*R) dissipation, compression and of course distortion. Simple response trends can easily be adjusted so long as the shape is not a symptom of another problem. Even more possible options open up if you add delay capabilities to the arsenal.

In the case of actual product design I do, I wouldn't likely bother making a system active, and much more expensive, unless I was able to implement something not practical or possible in a passive design. Similarly I'm doing some things in driver selection/design and alignment with passive designs that make little or no sense in an active system. Jeff Bagby mentioned that his free software now allows modeling of passive crossovers with modeled drivers as LspCAD and a few others have done for a while, and I urge DIYers to spend more time looking at the interactions and considering different targets for driver selection.

[Dennis H]

It appears enough have done some digging online to find the SpeakerPower amplifiers as the look is unique enough.

I cheated. John J let the name slip so I googled them and I figured you might be using them too.

Likewise, if you look at the response shapes and impedance curves of many compression drivers, it should be obvious that simple passive networks will never get the response as flat as many are used to with a dome tweeter.

Boy howdy on the simple bit. This is the Zobel network JonMarsh came up with for a BMS driver in a DDS waveguide. It's just to flatten the impedance and he hasn't even started flattening the response or rolling off the low end yet. :E