Speaker Build - Seas Idunn floor standers with L26ROY side firing subs

[alexm84]

Hi all,

I have decided to build another Seas idunn kit http://www.madisoundspeakerstore.com/2-way-speaker-kits/seas-idunn-2-way-speaker-kit-pair-parts-only/

I want to make them a 3 way set and build them as floorstanding speakers using the Seas L26ROY sub at the base http://www.madisoundspeakerstore.com/approx-10-subwoofers/seas-l26roy-10-subwoofer-d1001-04-4-ohm/

I have seen something similar done here http://i15.photobucket.com/albums/a397/tigradekat/overzicht1.jpg which i would like to do but with different boxes.

Not having any experience with box design or crossover design i was hoping i can ask some advice before purchasing the drivers.


My first question is, how would you go about running this setup? I was going to get a Crown XLS1000 amp to run my current subwoofer anyway. So am i right in thinking i can just buy the seas idunn kit with the 2 way crossover and run this off a 2 channel amp? Then run the 2 subs off the Crown? I was thinking the receiver front pre outs would go to my 2 channel for the idunns and the LFE (subwoofer) output to the crown. Is this the best way to go?

[alexm84]

Another question,
Can I have ports at the rear of the speaker.

I will build the top part of the speakers the same as my current 2 ways. But I'd like the port to be facing back to hide it from view and make the speakers better looking. Is there any problem doing this?

[Reffc]

Another question,
Can I have ports at the rear of the speaker.

I will build the top part of the speakers the same as my current 2 ways. But I'd like the port to be facing back to hide it from view and make the speakers better looking. Is there any problem doing this?

There may be issues depending on room acoustics and how close to the corners you have them. I find it better to side or front vent ported speakers as you can get boom issues when firing them close to a rear wall which can muddy the bass. If you don't like the way they look, use acoustically transparent cloth and cover the ports or the fronts of the speakers.

RE your points in post #1, you cannot just add a 26cm woofer to a cabinet designed as a 2-way using the 18cm woofer. Speaker cabinets are designed in size and port tuning around the main woofer so by adding the 26cm driver you would have to either use it in its own enclosure and spike the two way atop (is this what you had in mind?) BUT you would then have to test the 2 way for bass response, and where it is rolling off, design a crossover which meant rolling in the sub woofer to cross at that frequency. In effect, if kept as a passive design, you would need to design the crossover as a 3 -way crossover. By simply adding a sub woofer, without knowing its output level and frequency band of operation, you wont know how it will interact with the 2 way and the results could be interesting!

[alexm84]

Thanks for the info.
Yeah I was going to have the enclosures separated. So the sub in a sealed box and the 2 way on top. Still all as one floorstanding box but split internally to separate the two. Will this be OK spiked on the floor. Or will the sub create too much vibration in the 2 way if they share the same front rear and side panels?

I could always build the sub's in separate enclosures and spike the 2 way's on top like you described. What is the best tool to use to design the box dimensions for a sealed enclosure?

The crown amp has adjustable crossover from 50hz to 3KHz and a few different crossover modes so I can have the sub's roll of where required. Madisound mentioned I could build the two way part as normal and seal the port using a plumbers plug which would have the mid's start to roll off at about 100Hz. That's why I thought to run the crown to the sub's, so I can adjust the crossover set point as required.

[Reffc]

You can share the same side panels but it might be better to have separate boxes for stiffness and better isolation of the mid/HF.

The cabinet volume for the 2 way was calculated for porting, and by blocking off or eliminating the port you change the system "Q" and create a sealed enclosure with a very different response. You'd really need to recalculate the box volume required for a sealed box in preference to building the volume for a ported enclosure. If you use something like WinISD, you can recalculate the box size, run the 2 way as a sealed system and integrate the sub as planned using the crown amp crossover, however, the midbass was not designed for anything other than vented enclosures.

The midbass unit for that kit has been optimised for ported enclosures (and TL enclosures) and you may find that its too electrically damped for use in a sealed box. Your best bet is to use it exactly as the kit suggests and integrate the sub below woofer roll off or look for a sealed 2-way kit and add the sub. My preference might be for the sealed design with sub but this would mean searching out another kit designed as a sealed enclosure.

[alexm84]

You can share the same side panels but it might be better to have separate boxes for stiffness and better isolation of the mid/HF.

The cabinet volume for the 2 way was calculated for porting, and by blocking off or eliminating the port you change the system "Q" and create a sealed enclosure with a very different response. You'd really need to recalculate the box volume required for a sealed box in preference to building the volume for a ported enclosure. If you use something like WinISD, you can recalculate the box size, run the 2 way as a sealed system and integrate the sub as planned using the crown amp crossover, however, the midbass was not designed for anything other than vented enclosures.

The midbass unit for that kit has been optimised for ported enclosures (and TL enclosures) and you may find that its too electrically damped for use in a sealed box. Your best bet is to use it exactly as the kit suggests and integrate the sub below woofer roll off or look for a sealed 2-way kit and add the sub. My preference might be for the sealed design with sub but this would mean searching out another kit designed as a sealed enclosure.

Thanks again for all the info.
I really wanted to run the same kit as i have them already and that way they'll all match. I might run separate boxes for the subs and have the 2 way spiked on top. i'm still reading up on box design and response etc so will keep it simple while i'm still learnign. i suppose by leaving the kit as it was supposed to be and having the sub woofers separate, it would be no different than just adding subs to my current speakers and crossing them where necessary.

This sounds like the simplest approach at the moment. At least i'll have all the drivers, so i can always change enclosures when i have learnt a bit more.

Thanks again. I'll post up the build in this thread once i get all the bits.

[Reffc]

Thanks again for all the info.
I really wanted to run the same kit as i have them already and that way they'll all match. I might run separate boxes for the subs and have the 2 way spiked on top. i'm still reading up on box design and response etc so will keep it simple while i'm still learnign. i suppose by leaving the kit as it was supposed to be and having the sub woofers separate, it would be no different than just adding subs to my current speakers and crossing them where necessary.

This sounds like the simplest approach at the moment. At least i'll have all the drivers, so i can always change enclosures when i have learnt a bit more.

Thanks again. I'll post up the build in this thread once i get all the bits.

Exactly this. It would be the simplest approach tbh.