How do I chain angular filters that use checkboxes

I have a list of items and I need 3 filters for it. 1 of the filters is a simple name search. 2 of these filters are checkboxes that a user can toggle to adjust their data.

Previously, when I wasn't using checkboxes (and only allowing a single value for each filter), the below line allowed all filters to be used:

'<tr ng-repeat="item in data.itemList | orderBy: orderField | filter: {attr1 : a1Value} | filter: {attr2: a2Value} | filter: {attr3 : a3Value}">'

But now that I'm using checkboxes, this no longer works. Here is what I am trying so far. HTML:

'<!--list of checkboxes-->
<dl>
    <dt ng-repeat="type in data.att1List">
       <input type="checkbox" ng-model="a1Obj[type]">
    </dt>
</dl>
<!--...-->
<!-- list of data items -->
<tr ng-repeat="item in data.itemList | orderBy: orderField | filter: {attr1 : a1Filter} | filter: {attr2: a2Obj} | filter: {name : nameValue}">
<!--...-->'

in the controller i have:

'$scope.a1Obj= {
    'type1' : true, <!-- initialize 1 checkbox -->
    'type2' : false,
    'type3' : false 
};`

$scope.a1Filter = function (itm) {
  return $scope.a1Obj[itm.attr1];
};' 

What am I missing? Does anyone have any insight on chaining multiple filters where 1 or more are checkboxes?