Multiway SEAS Speaker design questions

I’m looking at building a new HIFI and at present are in the process of selecting components.

The system will be a DAC with DSP -> AMP -> 2 way speakers bi-amped with active crossover. I have the scope to add a sub later if I feel it’s needed. I also have the gear and understanding to take measurements & implement for active crossover.

Based on my research my current thinking is;
1. DAC - miniSHarc DSP + Buffalo III DAC
2. Speakers – SEAS W18NX001 + T25CF001 (there are a few plans around based on these so I can easily change cabinets if desired).
3. AMP - HYPEX 4 x UcD180HG with HxR


My Questions;

1) HYPEX Modules – The UcD180HG with HxR will be sufficient to power the proposed speakers, but I’m wondering whether it’s worth considering upgrading 2 of the modules to the UcD400HG w/HxR for the W18NX001 drivers for additional headroom (n.b. The W18NX001 is rate at 90W RMS continuous into 8Ohms). Therefore UcD180HG for the highs UcD400HG for mid lows. Is this just overkill?

2) For the tweeter, a potential upgrade would be T29CF002 but is a massive step up in price vs. the T25CF001. I am considering the T29CF001 as a substitute but is still double the cost of the T25CF001. Would it be worth it? What can I expect?

3) Speaker Porting – If I was building a Sub I’d definitely go closed box for the benefits of a flatter response (understanding impact on power requirements). Can the same be done for Mains (i.e. sealed box)? I don’t see a lot of un-ported designs so am wondering if there’s a reason why other than efficiency? I’m thinking of trying say the SEAS Bifrost or Troels CNO-T25 designs but un-ported.

Any thoughts and experience with the above appreciated.

Thanks in advance
 
The sensitivity of a woofer is not related to whether there is a port or not. This only affects the bass extension and of course excursion.

Having a sealed design ends up close to 2nd-order low pass. Convenient for satellites, since adding 2nd order creates new 4th-order. Match with sub having complementary 4th order low pass. At least in theory. :)
 
2) For the tweeter, a potential upgrade would be T29CF002 but is a massive step up in price vs. the T25CF001. I am considering the T29CF001 as a substitute but is still double the cost of the T25CF001. Would it be worth it? What can I expect?
Judge by yourself: Zaph|Audio

3) Speaker Porting – If I was building a Sub I’d definitely go closed box for the benefits of a flatter response (understanding impact on power requirements). Can the same be done for Mains (i.e. sealed box)? I don’t see a lot of un-ported designs so am wondering if there’s a reason why other than efficiency? I’m thinking of trying say the SEAS Bifrost or Troels CNO-T25 designs but un-ported.
You can do it, but don't expect real bass from it, as this Seas woofer has been designed for a ported box. Just to put some numbers on it, a 5L sealed enclosure will give you a -6dB point at around 70Hz, while a 15L ported box tuned to 45Hz will give you a -6dB point at around 40Hz. Going active can give you some bass gain though, but I never did it so I can't comment.

Ralf
 
How about the miniDSP ICEpower based units? 2 amp channels + DSP all in one.

Plate Amplifiers : PWR-ICE125

Solves quite a few problems at once! :)

E

Hi eriksquires,

The pwr-ice series is a suitable contender, had a bit of a read and like what it offers as an integrated package but is not what I'm looking for in this project as;



1. Intergrated solution creates concerns around product lifecycle, thus cost effectiveness


2. The AMP modules are Ice power based right (which I assume this means the B&O Icepower range). If so, my research indicates they are greatly inferior to other options of similar price.


Please feel free to correct me if i am wrong.
 
1- Under $300 per speaker is really good. I didn't think your make up was better. Also, just what exactly are you going to need differently? If you see yourself upgrading every chance you can then yeah, I see your point. On the other hand if you want a great solution and want to be done with it, that makes no sense, and in fact is more expensive as the amps you are thinking of are pricier, and you plan to churn through several over the speaker lifetime?

Make yourself happy, but you aren't selling me on price effectiveness! :D :D

2- I have ICEPower 250ASP monoblocks. I used to have Parasound A23s. I could not tell an audible difference. While I understand Hypex has a lot of hype, and I am tempted to buy a pair of nCore monoblock kits for my L/R speakers, but personally I'm just really happy with what I have.

Best,


E
 
Judge by yourself: Zaph|Audio


You can do it, but don't expect real bass from it, as this Seas woofer has been designed for a ported box. Just to put some numbers on it, a 5L sealed enclosure will give you a -6dB point at around 70Hz, while a 15L ported box tuned to 45Hz will give you a -6dB point at around 40Hz. Going active can give you some bass gain though, but I never did it so I can't comment.

Ralf

Have spent time looking into this and understand now where you are coming from (i.e. been exploring the Sealed / Ported Calc).

There seems to be more design options out there for ported speakers although the 18W/8531G gives best of both worlds. Zaph liked it, Troel's seems to be warming to it after initial comments around non coated paper cone drivers adding colouration.

At this point I'll prioritise ported options with sealed as a nice to have.
 
Judge by yourself: Zaph|Audio

Ralf

Trying to pick a standout winner amongst SEAS options is a tough one.

Zaph generally appears supportive of the T25CF001. Based on comments on the more expensive options I didn't get a sense this was proportional to price. Even the cheaper < $100 options fair well comparatively.

At this point I'm thinking the T25CF001 given the smoothness across the range and 1 cross over point of the 2 way design. If i went down the 3 way path a cheaper option cross higher would suffice.

I did observe some of the cheaper SEAS have nasty spikes around 30k. Not that I could hear that, but I'm sure my dogs won't like it.
 
Hi Wright,

I did settle on a design and have thus far built my speakers and amp, but not the sub's as yet. Still some minor tweaking to do when I find the time…



For the Speakers

  • Troels CNO-25 – pretty much to plan, but
    • Made out of MDF
    • Front baffle is 36mm slightly larger than plan but internal dimensions maintained. Why, I could glued 2 x 18mm sheets together.
  • Mod’s – since the plan was to actively bi-amp, have installed a 4 core Neutrik Speakon socket and wired with Van Damme 4 core pro series speaker cable (might not be the exact name)
  • Speakers – Woofer’s W18NX001 and Tweeter T29CF002. Why? Well whilst expensive wasn’t material in the overall project cost so thought why risk? Still don’t know if they are that much better than the SEAS T25CF001…but I’m not losing sleep over it.


For the amp

  • 4 x UcD180 w/HxR’s to biamp the CNO-25’s. powered with 2 * SMPS400A180’s
  • On the DAC I went with the Hypex DLCP in the end (shift in direction). Why?
    • Simplicity – all in one solution for DSP and DAC, 6 channels for 2 * 3 way.
    • miniDSP – feedback is mixed, generally need a separate DAC solution if hi end
    • DLCP
      • Overall great product
      • USB input is only 16-48. Need to use SPDIF or AES for higher…really just a function of product life-cycle


Plan for the Subs

  • I haven’t started the build but have parts ready to go
    • Will be Sealed SUB’s
    • 2 x SEAS L26ROY
    • 2 x UcD400’s to drive (I dropped the HxR on these as I understand no audible benefit as low frequencies). A SMPS400A400 to power


And the result

  • Overall I’m satisfied but looking to optimise a few things before I pass judgement.
  • As documented, Troel’s CNO designs can lack in bass response. I have found this to be the case if I crossover and do not apply room correction EQ.
    • Active EQ’ing changes this paradigm somewhat. Particularly when the DSP and DAC implementation are great (i.e. Hypex DLCP). Having said that, at loud volumes and the mood confirms would be good to have a bit more bottom end on tap to move some air...
    • The Sub’s I have planned will address this. When I get there it will be interesting as to where to cross the SUB’s and the CNO’s i.e. how low do I want the Sub’s to go??? How much lower mid to pass to CNO woofer’s etc. So many possibilities.

I’ll post some photo’s of the build soon.
 
I've always wondered about the quality/value of Seas, Scanspeak & SB Acoustic when it comes to subwoofers. I feel there is more competition for good drivers in the subwoofer market than for other drivers. I got my CSS SDX10 for 1/3 the price of a 10" Revelator and half the price of a Seas or SB Acoustics and it is supposed to have 18+mm one way excursion capability. It is a great driver but leaves me wondering if you do get anything better with the more expensive brands. As it is, I got 4 of them for less than the price of a pair of Revs so I would think that not having to push them hard at all is likely to keep them in a more linear range.

http://creativesound.ca/pdf/CSS-SDX10-data-140408.pdf
 
I've always wondered about the quality/value of Seas, Scanspeak & SB Acoustic when it comes to subwoofers. I feel there is more competition for good drivers in the subwoofer market than for other drivers. I got my CSS SDX10 for 1/3 the price of a 10" Revelator and half the price of a Seas or SB Acoustics and it is supposed to have 18+mm one way excursion capability. It is a great driver but leaves me wondering if you do get anything better with the more expensive brands. As it is, I got 4 of them for less than the price of a pair of Revs so I would think that not having to push them hard at all is likely to keep them in a more linear range.

http://creativesound.ca/pdf/CSS-SDX10-data-140408.pdf

SEAS, Scan, SB Acoustics, etc all make great subs. Fit and finish are excellent and the motors generally exhibit very low distortion. Maybe even worth the price.

On the other hand, I have to agree with your point about the CSS SDX10. With the XBL^2 motor and 18mm xmax, it will easily hold its own in all regards with the more expensive drivers mentioned. The SDX12 is even more capable (28mm xmax). These drivers are a bit of an anomaly in our hobby though. You generally need to pay more than CSS prices to get this kind of performance. You guys in Canada have been tuned into these gems for quite a while. Maybe now that CSS is in the States, some more folks will catch on.

Dan
 
Prices gone up , I have 4 peerless xls-10 witch I paid little under 400€ many years ago. At that time I felt
it was enough vs performance wise . For my use as my listening space is small .
Now days they doubled in price.
Seas has become expensive , SEAS L26ROY 243,60€ here in finland is pretty steep for what it used to cost. Scan speak relevator series subs has always been not so wallet friendly but good though they have not doubled the price .
As for Css if i recall it used to be 249€
nowdays CSS SDX12 499€ .
Some use the dayton 18" for home theater in 390€ from loudspeakerfreaks.com in europe but not in stock.
RSS460HO*4 18" 402€
i think it's ok . 2 of those insted of four 10" whatever with big xmax seems as a good option for the sub.
Two 15" dayton 600€

Thoughts!

Now of to work
 
Yeah the prices have been going up for sure. They also vary a lot depending on where they are distributed from I guess. When you figure exchange rates, europeans get better prices on Euro brand drivers (go figure). I got my SDX10s for $150+tax each Canadian I believe. Figure that out in todays exchange rate!
 
my 10c worth.

Well I'm in Australia everything comes at a substantial premium.

Options are:
- Buy locally at triple the US price
- Import and pay for the freight - gets expensive on 12kg sub drivers...

But it is what it is.

If I get bored one way I'll cluster my component costs, but freight was definately a cost driver for my overall cost, hence getting the premium SEAS tweeter was immaterial.
 
As promised, some quick photos of my first DIY of Speakers & Amp.
All cabling DIY...

Connection is easy as
- SPDIF
- USB
- Left / Right Speakon (each bi wired)
- Power

As we say in Australia. Off ya go!

When I add 2 x subs will be just 2 more speakons to connect.
 

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Hi Wright - I've started the build of my 2 subs with the SEAS L26ROY.

Cabs are cut and glued and started priming internally. Will be 28L internal sealed box which should realise a Qtc of 0.643.

For the size of the box, many will say over engineered but its done.
- 36mm baffles
- 27mm sides
- 18mm bottom
- bracing is in 100mm incr.

Internal dimensions are 240W * 310d and 390w which deliver 29L with about 1L for bracing.


I like your question around where I will cross these over and placement.
- Easy question first, they will be placed next to each tower.
- Crossover - I'll need to experiment but I'll start with a range of 120Hz to 200Hz and see what that delivers. Some might consider these as the bass cabs of a 3 way setup at the highrt end.

Updates to follow.
 

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Those subs look like they would hold up a truck. Well done! I'm very curious to see where you end up settling on the crossover, and how the LROYs do higher up. Does the DLCP allow you to adjust the roll-off of the CNOs so that the subs can cross in smoothly? One more question, are you using the DLCP as your preamp, or do you have other gear in the system?
 
Does the DLCP allow you to adjust the roll-off of the CNOs so that the subs can cross in smoothly?

Yes - the DLCP has 6 channels each with 15 filters. In this case I have 1 channel per speaker. Filters can be stacked to achieve various filters at crossover points. e.g. buterworth, bessel up to 6th order

The L26ROY's recommend frequncy range is 20-1000Hz although I don't know how well it does at the higher end.

On the SEAS website is a DIY plan for the KingRO4Y MkII which uses a L26RO4Y. If I'm reading this correctly crosses bass to mid with a LR4 filter at 233Hz.

One more question, are you using the DLCP as your preamp, or do you have other gear in the system?

My source is a PC streaming everything at 192KHz at 24bit via JRiver.
I use a Schiit Audio EITR to convert USB to SPDIF.
This then correct to the COAX input on the DLCP.

I then set the DLCP master volume at the maximum level I need which never moves.
Volume is adjusted then on the EITR via JRiver.