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Home / Product Category / SPEAKERS / In Wall Speakers / In Wall Subwoofers / In Wall Subwoofer OSD IWS88 Dual 8" Injected Woofers Back Bridge Plate (2018 New Design)

In Wall Subwoofer OSD IWS88 Dual 8" Injected Woofers Back Bridge Plate (2018 New Design)

Product code: OSD-IWS-88

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Features & Specifications

Brand new for 2018 we improved the lower end of our popular dual inwall subwoofer. By adding a strong reinforced back plate to stiff the structure of the subwoofer, we make it to sound deeper and clean. A subwoofer is designed to reproduce the lowest of audible frequencies and will give you that spine-tingling rumble effect that takes you out of reality and into the plot. With dual 8" Injected polypropylene woofers, bigger magnets and 350 Watts of power handling, the IWS-88 in-wall subwoofer performs excellently for home theater surround sound applications as well as for listening to music. Like all OSD Audio speakers, the IWS-88 includes a dog-ear bracket system that mounts securely to the sheet-rock after the cut-out hole has been made and the speaker has been dropped into the hole. The grille is paintable to match your room decor and we even include a cutout template that doubles as a paint shield. You'll experience thunderous, room-filling bass without filling up floor space.

Amplifier Suggestions
Because this is a passive speaker, it will require a subwoofer amplifier to power it. An ideal match to this subwoofer is our OSD SMP500 dedicated subwoofer amplifier that features 400W RMS @ 4 ohms, Variable High Cut Filter 30Hz-150Hz; front panel Knob, and Choice of Signal Level Input or LFE (Low-Frequency Effects).

*Note: Requires Additional Subwoofer Amplifier




  View Owner's Manual          


24 Questions & 25 Answers
from Templeton, California asked:
August 5, 2019
Will I need an amp in addition to my Denon AVR receiver with the sub port?
1 Answer
Hi Stephan:

Yes, you will need a dedicated subwoofer amplifier simial to our SMP300 or SMP500 DSP Digital Amplifier. Both can do a 4-ohm load like that featured on the IWS88.


Submitted by: Tim Leahy on August 13, 2019

from Wilton Manors, FL asked:
July 18, 2019
I ordered two of these can I adjust the internal wiring so I can have a series/parallel so I end up with a 4 ohm load?
1 Answer
Hello Andrew:

The IWS88 is a 4-ohm subwoofer already meaning it has 2 8 ohm drivers wired in parallel. When wiring two together you would get a 2-ohm load in parallel and 8-ohm in series. If you series-parallel the four 8-ohm drivers, you will still get 8-ohm. Now if you bought four IWS88, to begin with, and series-parallel them together, you would get your 4-ohm load, and our SMP500 would be the perfect amp to drive them. Did you buy them directly from us; we could offer you a bundle discount for purchasing the two additional IWS88 (and the amp as well)? The four speakers in series-parallel would dramatically raise the power handling and sensitivity while cutting down on distortion. Please let me know if you are interested;


Submitted by: Tim Leahy on July 19, 2019

from Seattle asked:
December 5, 2018
Two questions: 1. Do you recommend placing foam or dampning material behind the sub inside the wall? Or just keep the wall cavity as is? 2. For two subs, what amplifier do you recommend? What's required? Thank you, Ricky
1 Answer
Hi Ricky: The dampening material can be used to tune the sub in your wall. I would experiment without filling, then with filling to see which you like the best. Typically fiberfill is added to make the Subwoofer think it is a larger cavity. The SMP500 would be the best for the Subwoofer especially if you want to power two subs. You would need to run them in series so the amp would see an 8-ohm load versus two in parallel since that would drop the two four ohm speakers down to a 2-ohm load which it would not like. The biggest bang for the buck would be purchasing 4 of the Subs and wiring in Series-parallel, so the amp sees a 4-ohm load. It drives up the sensitivity (making the subs much more efficient), and now you have the cone material of eight 8" subs. Then you are getting the most out of the SMP500. TL/5320
Submitted by: Tim Leahy on December 9, 2018

from Lexington, KY asked:
January 14, 2018
Is this unit suitable for damp locations? I would like to mount it on a covered porch.
1 Answer
Hi Ford: Most in-wall open back subs and this one is no exception need to have some sort of reinforcement built around the speaker. It needs to be sealed with weatherproof silicon including all the seams of the box and also a bead of silicone should be applied on the inside of the frame so you seal around the cutout hole. It should be fine, Kentucky has humidity and temperature swings but no salt water or any of the extremes found in the deserts of Arizona or the Humidity of Florida during the summer. Note the enclosure size is not critical because of the infinite baffle design of the two drivers. There designed to adapt to almost any space you place them. It is also recommended using fiber fill to help tune the enclosure. The more fiber fill added the speaker will think it is in a bigger enclosure. Good luck TL/4750
Submitted by: Customer Service - Q&A on January 18, 2018

from New Zealand asked:
January 7, 2018
What is the power output (RMS/max) for these speakers? Your website says 350W compared to the OSD website which states 240W.
1 Answer
Hi Evan: 350 watts would be peak with 240 Watts RMS. Performance may vary depending on whether you design an enclosure for the Speaker. TL/4733
Submitted by: Customer Service - Q&A on January 15, 2018

from Indiana asked:
October 25, 2017
Would this be safe to mount in the ceiling or is there a better product for that?
1 Answer
Hi Nick: Yes these will work in a ceiling as will all of our in-wall subs but it is good idea to create some sort of enclosure to reinforce the speaker so it is not playing more bass above the ceiling. Stuffing the enclosure with fiber fill (like for Pillows) will help you tune your speaker. The fiber fill absorbs the low frequencies making the woofer think it is in a larger enclosure. Checkout our SL800 on-wall sub which features a quasi sealed enclosure with an 8 inch active woofer and 10" passive Woofer. It s too deep to fit into a wall but would fit between two ceiling joists and already features a tuned enclosure. Just a thought. Good luck TL/4609
Submitted by: Customer Service - Q&A on October 27, 2017

from Hoffman Estates, Illinois asked:
October 14, 2017
I want to put 2 of these in a 2 story 20ft by 20ft family room. I know that acoustics are not going to be that great in a 2 story room but wanted to know if this is overkill. Both subwoofers will be placed on the same wall - pic attached. Any help/advice greatly appreciated! Thanks!
1 Answer
Hi Matt: Two woofers are always better than one, there is a real reason AV receivers went to dual Subwoofer outputs as in 5.2 or 7.2. Even though Sub woofers are omni directional in nature versus the highly directional characteristics of the Tweeter with the High Frequencies. Due to wider Sign waves of the lower Frequencies when you use just a single sub woofer you will experience dead spots in your room. Adding a second sub woofer greatly negates this effect. So I would not call it overkill. Will you be able to build an enclosure or at least re enforce the area around the sub. It is also a good idea to use some fiber fill behind the sub so it thinks it is in a bigger enclosure. Our SMP250 Sub amplifier would be ideal for the job as well. Good luck TL/4592
Submitted by: Customer Service - Q&A on October 17, 2017

from Houston, TX asked:
June 20, 2017
Hello, I just purchased the IwS88 with the SMP250 and was planning on installing it into the wall where my air ducts run through. It is a tight space but this it is the main duck space that runs from the second floor to the fourth floor attic. along with cat 5, coax, electrical, etc. Because it is sealed should it be set it up as an infinite baffle? The builder's contractor placed rca and speaker cable on the second floor in the duct space to the main speaker demarcation point. I am thinking they did this to be able to place a in-wall sub woofer. Just want to see if I will be ok, or should I go with the Sl800 instead? I have included pictures of the environment and I am glad I didn't start cutting drywall just yet. lol. Love your products OSD. Thanks for the advice.
1 Answer
Hi John: The SL800 is much better for your application. It is always more advantageous to have a sub woofer that can be placed around the room to find the best location where you will hear the most low frequencies while sitting at your optimum viewing/listening position. Either speaker needs a True Subwoofer amplifier like our SMP250. It is true that the Sub woofer is Omni-directional but due to the size of the Sign wave produced by the low frequencies there tends to be dead spots around the room when using only a single Sub. When trying to determine the best location you are limited with an In wall sub that does not feature a sealed enclosure. You can not experiment on different locations like you can with the SL800. In fact we recommend during setup that you place the SL800 on the main chair/couch where you will be sitting. Now while playing your sub you will need to walk around the room checking out the three locations your wife (if you are married) will allow for the sub to be placed. That will be the optimum location for the SL800. You also have the option of adding a second SL800 powering both with the single SMP250. Two subs helps eliminate those dead spots as well. Ironically the SL800 was designed as an in-Wall Sub but they could not get the depth low enough without sacrificing the excellent sound quality. Good Luck TL/4434 PS: Did I see clear jacketed speaker wire in your image wrapped around the duct? Does the outer jacket say CL2 or CL3?
Submitted by: Customer Service - Q&A on June 25, 2017

mike padilla
from c asked:
October 17, 2013
what is the optomal location for this speaker, front or rear? and what is the ideal height? can i install at 7' high
1 Answer
Hi Mike: That is a tough question. Probably the best location is the one that is most accessible for your wiring from your Sub-woofer Amplifier. And you also need to take into consideration the idea of mounting the speaker in the wall with an internal enclosure to make sure all the sound is focused into the room and not bleeding out the back. You need to pick an area where you can build the enclosure. Also if you budget allows it think about adding a second IWS-88 to be mounted opposite of the first , so front and back as an example. There is a reason the Receiver companies are now promoting 7.2 systems which call for two Sub-woofers. The problem with just one sub is that with the large sign waves from the sub there is a tendency for dead spots in the smaller room. So adding a second Sub-woofer is recommended to fill in the gaps. The advantage of a stand alone external Sub-woofer is you can experiment with the location moving it around the room to find the optimum spot. I hope that helps TS-2281
Submitted by: Customer Service - Q&A on October 18, 2013

Patrick Skomer
from Eagle, Ne asked:
February 18, 2018
I just purchased the iws88 and the 250 watt amp for a new construction I’ve got lot of room under the propane fireplace to build a sealed box or should I port the box into the room? I have enough room to build a box that’s 2-7 cubic ft whats optimum?
1 Answer
HI Patrick: It might be worth while to build a ported box with the ability to block the port to do a comparison. Also many people using Fiber fill to help tune a box. You just want to line the inside walls actually gluing the poly fill. This was from Turbo Future: Which Is Better? A Sealed or Ported Subwoofer Design? There are quite a few different designs out there. If you're going DIY, you need to think about what you're going to build. In this guide I'm going to talk about the two main types, which are sealed and ported subwoofers. There are pros and cons to both types. There is a lot of information on this out there, so I'm not going to go too in depth with this or I'll be here for years. So, I will give a basic outline of the differences. Sealed This is a driver inside a sealed box. The drive unit is damped by the air inside the box. As sound gets to the limits of excursion, there is a lot of damping from the air, which means that you need a lot of power to drive it. If the enclosure has been made properly, then it will be airtight. Ported This type of subwoofer has a port which lets air in and out of the box freely as the drive unit moves back and forth. This will boost the output of the sub so it can play louder. The driver is not damped by air inside the enclosure, so less power is needed. Pros and Cons Now, there are pros and cons to both designs. A sealed subwoofer can be smaller than ported ones. The sound quality of a sealed sub is generally thought to be superior, although this is something that is debated, with people belonging to both camps. Since the driver is damped and the port doesn't boost the output, a lot more power and equalisation is needed to get the equivalent SPL levels of a ported sub. If you have a lot of power available, then its not necessarily a problem. But, this is something worth bearing in mind. When you're building a DIY sub, you can often find a way to accommodate either design. There is usually some space that can be utilized, in even the smallest room. TL/4809
Submitted by: Customer Service - Q&A on February 19, 2018

from GA asked:
August 3, 2017
Will this mount in a 2" x 4" framed wall for depth (assuming lumber is 3 1/2" deep + faced with 1/2" gypsum board)?
1 Answer
Hi Kevin: The depth of the IWS-88 is 3 9/16 just a shade over 3 1/2. You have 3.5" stud with the additional 1/2 inch of the Gypsum board so it will fit.. TL/4504
Submitted by: Customer Service - Q&A on August 4, 2017

Brian Holland
from Tyler, TX asked:
January 19, 2017
Does this speaker come with the paintable grille, I do not see it in any of the product pictures
1 Answer
Hi Brian: The Speaker includes a paintable grill shipped with it. TL/4185
Submitted by: Customer Service - Q&A on January 24, 2017

from USA asked:
June 14, 2016
Can you recommend a non-ported enclosure volume for the IWS-88 subwoofer? I have to install a pair in a large open ceiling void, and I'm guessing it will work much better if we box out a part of that void before installing the sub. Hence the need to know what volume will give best overall perfomance. The room it has to support is large (over 500 sqft) and it will be supporting 3 pairs of 8" in-ceiling speakers. Not ideal, and I know that two would be better than one, but it was a battle just to get this one in the mix
1 Answer
If you want to build a back box, make sure it is at least the same size of the width and length of the speaker, but at least 4 to 7" deep, also please add some fiber materials inside.
Submitted by: Customer Service - Q&A on June 16, 2016

from Brazil asked:
November 22, 2014
I am planning to make a 7.1 system considering: MKIW550LCR for the central Chanel, OSD-MKW-850 for the LR front Chanel and I have a doubt whichr rear surround I need to use MK670 or MK690TT? Another doubt is which subwoofer I need to use IWS-88 or IWS-10? please help me to define my system. Thank you.
2 Answers
Hello again Max, You can use either speaker for the back, but if the back speakers are not somewhat above the sitting area, you could use the MK670 for the angle. For the sub, I personally recommend a powered floor standing sub such as the PS10 or PS12, because the in-wall subs need a subwoofer amplifier.
Submitted by: Customer Service - Q&A on November 26, 2014
Hello again Max, You can use either speaker for the back, but if the back speakers are not somewhat above the sitting area, you could use the MK670 for the angle. For the sub, I personally recommend a powered floor standing sub such as the PS10 or PS12, because the in-wall subs need a subwoofer amplifier.
Submitted by: Customer Service - Q&A on November 26, 2014

from Hamilton asked:
April 5, 2014
I have purchased 5 in wall OSD speakers so far. Very Happy. I want to add this to my system -by plugging this passive subwoofer into one of the dedicated sub outs - of my 7.2 receiver. What cable to I need? The back of my Sony receiver has an RCA available for this sub. Running an RCA male to exposed speaker wire seems like a nightmare. Please advise -and I will buy. Thanks
1 Answer
Hi Jon, You will need a Subwoofer Amplifier to power the IWS-88. The Sub Amp will have a built in crossover which will separate the high and low frequencies and will only send the low frequencies to the amplifier. You will use a subwoofer cable to run from the receiver to the Sub amp. I suggest looking at the SMP250. CS 2599
Submitted by: Customer Service - Q&A on April 7, 2014

from Chicago,Il asked:
April 2, 2014
Tim from Chicago again. ( See question from last week) I asked the question about using IWS-88 and powering it with the Yamaha RX-V 575 7.2. 1. Yamaha's connection for the subwoofer calls for a audio pin cable. How do I convert the speaker wire I connected at IWS-88 and pulled to the RX-V575 to a audio pin cable? 2. On page 4 of the Yamaha's directions, they say to use a subwoofer with a built-in amplifier. Per the question I asked last week, the answer was the RX-V575 has enough power for the IWS-88. HELP!!!!!!
1 Answer
Hi Tim, You would need a subwoofer amplifier in order to power the in-wall subs. Our SMP60 can power the IWS8, and our SMP250 will power the IWS-88 and IWS10. Unfortunately we are out-of-stock on both amps for another month or so, but you can't really run these subs with a stereo amp/receiver such as your Yamaha. The reason being that these subs don't have crossovers to filter out the highs, so you need an amp that does that for them. -BM 2591
Submitted by: Customer Service - Q&A on April 3, 2014

from chicago.Il. asked:
March 22, 2014
Can I power this subwhoofer duel 8" IWS-88 with a receiver such as the Yamaha 7.2 RX V575, I would like to avoid spending 299 on the SMP250 and having more equipment added my bookshelf. If not, is there another 7.2 receiver that would work at a reasonable price please let me know. I have in wall OSD speakers in place and would like to add this in wall subwhoofer to complete my system.
1 Answer
Hi Tim, As long as you are using a 5.1 or 7.2 Receiver, they have enough power for the subwoofer. A receiver would have a Subwoofer channel with a built in crossover to separate the highs and lows frequencies, A 2 channel Amplifier would not have the crossover to do this. CS 2556
Submitted by: Customer Service - Q&A on March 24, 2014

from St. Catharines ON. asked:
March 14, 2014
Hello, I have 7.1 Pioneer amp in my kitchen . I run it in stereo on two in ceiling speakers. Can I run these subs powered from my available empty channels on the receiver directly to each of these speakers ?I have already prewired in wall with 2 runs of speaker cable to same location. Thank You
1 Answer
Hi Gary, I would suggest getting a Sub amp to power the IWS88s as a 7.1 receiver would not have enough power for both subs. Check out the SMP250. That would be enough for both of those. CS 2537
Submitted by: Customer Service - Q&A on March 17, 2014

from BALTIMORE asked:
April 30, 2013
1 Answer
Hi Eric, This in-wall subwoofer is passive and requires a subwoofer amplifier, such as our SMP250, to power it. The connection from the subwoofer to the amp is speaker cable. CL/MA 1845
Submitted by: Customer Service - Q&A on April 30, 2013

from new york asked:
February 22, 2013
I was thinking about purchasing this speaker. It says cinema meaning home theater. Is it also good for music?
1 Answer
Hi Gary, The IWS88 in-wall subwoofer is a great balance between performance and price. This subwoofer performs excellently for home theater surround sound applications as well as for listening to music. CL/MA 1647
Submitted by: Customer Service - Q&A on February 25, 2013

from chicago, il asked:
August 6, 2012
Do you have a spec sheet on this speaker?
1 Answer
Hi Nim: We will need to create a spec sheet for this speaker which will post on the product page. Please stand by... TL
Submitted by: Customer Service - Q&A on August 8, 2012

from chicago, il asked:
June 29, 2012
i am building a home and looking for a pre-construction bracket for this item. I don't see one so how is is mounted?
1 Answer
Hi Nim: As you can see from the images on the product page the IWS-88 features an eight leg Dog Ear mounting system. It mounts securely to the sheet-rock after the cut-out hole has been made and the speaker has been dropped into the hole. We do recommend you create an enclosure behind the speaker in the stud bay. I am assuming since you are inquiring about a new construction bracket you will have access to the wall before the sheet-rock has gone up. We recommend adding a (2) 2x4 piece of stud material roughly 24 inches apart one above and one below where the speaker will be centered. Then you would add a 1/4 board to run between the two studs running vertically and the two pieces you have added above and below. So 24 " tall and 14 to 15 inches based upon the actual measurement between the two vertical studs. Then add a little silicon applied along the seams of the 1/4" backboard and the studs before you install the Sheet-rock and cutout your hole. There is a cutout template that doubles as a paint shield that you use to mark your hole. Lastly you will want to stuff the cavity with some fiber fill like you find at a bedding or hardware store. TL
Submitted by: Customer Service - Q&A on July 1, 2012

from Chicago, IL asked:
June 26, 2012
does this include a paintable grill cover?
1 Answer
Hi Mim: Yes all of our speakers have paint able Grills and Frames. And the paint shield is included with this speaker as well. TL
Submitted by: Customer Service - Q&A on June 27, 2012

from NW Indiana asked:
November 30, 2011
What type of amp is recommended for this subwoofer???
1 Answer
Hi Joe: The best Amp for the job is our OSD SMP250 (MI-3) dedicated Subwoofer Amplifier. It features 150 watts (Mono). It also features front panel controls, Phase switch, Frequency Control Knob (35 Hz to 180 Hz) and Volume control. Plus Three turn-on options; Music sensing, Manually switched or 12 volt trigger TL
Submitted by: Customer Service - Q&A on November 30, 2011

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